Nonsusceptibility of bacteria to the action of CHLORAMPHENICOL, a potent inhibitor of protein synthesis in the 50S ribosomal subunit where amino acids are added to nascent bacterial polypeptides.
An antibiotic first isolated from cultures of Streptomyces venequelae in 1947 but now produced synthetically. It has a relatively simple structure and was the first broad-spectrum antibiotic to be discovered. It acts by interfering with bacterial protein synthesis and is mainly bacteriostatic. (From Martindale, The Extra Pharmacopoeia, 29th ed, p106)
The ability of microorganisms, especially bacteria, to resist or to become tolerant to chemotherapeutic agents, antimicrobial agents, or antibiotics. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).
An enzyme that catalyzes the acetylation of chloramphenicol to yield chloramphenicol 3-acetate. Since chloramphenicol 3-acetate does not bind to bacterial ribosomes and is not an inhibitor of peptidyltransferase, the enzyme is responsible for the naturally occurring chloramphenicol resistance in bacteria. The enzyme, for which variants are known, is found in both gram-negative and gram-positive bacteria. EC
A class of plasmids that transfer antibiotic resistance from one bacterium to another by conjugation.
A methylsulfonyl analog of CHLORAMPHENICOL. It is an antibiotic and immunosuppressive agent.
Vertical transmission of hereditary characters by DNA from cytoplasmic organelles such as MITOCHONDRIA; CHLOROPLASTS; and PLASTIDS, or from PLASMIDS or viral episomal DNA.
Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.
Enzymes catalyzing the transfer of an acetyl group, usually from acetyl coenzyme A, to another compound. EC 2.3.1.
A parasexual process in BACTERIA; ALGAE; FUNGI; and ciliate EUKARYOTA for achieving exchange of chromosome material during fusion of two cells. In bacteria, this is a uni-directional transfer of genetic material; in protozoa it is a bi-directional exchange. In algae and fungi, it is a form of sexual reproduction, with the union of male and female gametes.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
Deoxyribonucleic acid that makes up the genetic material of bacteria.
The heritable modification of the properties of a competent bacterium by naked DNA from another source. The uptake of naked DNA is a naturally occuring phenomenon in some bacteria. It is often used as a GENE TRANSFER TECHNIQUE.
The functional hereditary units of BACTERIA.
An antibiotic produced by the soil actinomycete Streptomyces griseus. It acts by inhibiting the initiation and elongation processes during protein synthesis.
A naphthacene antibiotic that inhibits AMINO ACYL TRNA binding during protein synthesis.
The ability of bacteria to resist or to become tolerant to chemotherapeutic agents, antimicrobial agents, or antibiotics. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).
Substances that reduce the growth or reproduction of BACTERIA.
Any tests that demonstrate the relative efficacy of different chemotherapeutic agents against specific microorganisms (i.e., bacteria, fungi, viruses).
Structures within the nucleus of bacterial cells consisting of or containing DNA, which carry genetic information essential to the cell.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
Discrete segments of DNA which can excise and reintegrate to another site in the genome. Most are inactive, i.e., have not been found to exist outside the integrated state. DNA transposable elements include bacterial IS (insertion sequence) elements, Tn elements, the maize controlling elements Ac and Ds, Drosophila P, gypsy, and pogo elements, the human Tigger elements and the Tc and mariner elements which are found throughout the animal kingdom.
A species of gram-positive bacteria that is a common soil and water saprophyte.
Diminished or failed response of an organism, disease or tissue to the intended effectiveness of a chemical or drug. It should be differentiated from DRUG TOLERANCE which is the progressive diminution of the susceptibility of a human or animal to the effects of a drug, as a result of continued administration.
A bacteriostatic antibiotic macrolide produced by Streptomyces erythreus. Erythromycin A is considered its major active component. In sensitive organisms, it inhibits protein synthesis by binding to 50S ribosomal subunits. This binding process inhibits peptidyl transferase activity and interferes with translocation of amino acids during translation and assembly of proteins.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
Proteins found in any species of bacterium.
The most common etiologic agent of GAS GANGRENE. It is differentiable into several distinct types based on the distribution of twelve different toxins.
A species of HAEMOPHILUS found on the mucous membranes of humans and a variety of animals. The species is further divided into biotypes I through VIII.
Enzymes that are part of the restriction-modification systems. They catalyze the endonucleolytic cleavage of DNA sequences which lack the species-specific methylation pattern in the host cell's DNA. Cleavage yields random or specific double-stranded fragments with terminal 5'-phosphates. The function of restriction enzymes is to destroy any foreign DNA that invades the host cell. Most have been studied in bacterial systems, but a few have been found in eukaryotic organisms. They are also used as tools for the systematic dissection and mapping of chromosomes, in the determination of base sequences of DNAs, and have made it possible to splice and recombine genes from one organism into the genome of another. EC 3.21.1.
Any method used for determining the location of and relative distances between genes on a chromosome.
Any of the covalently closed DNA molecules found in bacteria, many viruses, mitochondria, plastids, and plasmids. Small, polydisperse circular DNA's have also been observed in a number of eukaryotic organisms and are suggested to have homology with chromosomal DNA and the capacity to be inserted into, and excised from, chromosomal DNA. It is a fragment of DNA formed by a process of looping out and deletion, containing a constant region of the mu heavy chain and the 3'-part of the mu switch region. Circular DNA is a normal product of rearrangement among gene segments encoding the variable regions of immunoglobulin light and heavy chains, as well as the T-cell receptor. (Riger et al., Glossary of Genetics, 5th ed & Segen, Dictionary of Modern Medicine, 1992)
The transfer of bacterial DNA by phages from an infected bacterium to another bacterium. This also refers to the transfer of genes into eukaryotic cells by viruses. This naturally occurring process is routinely employed as a GENE TRANSFER TECHNIQUE.
Use of restriction endonucleases to analyze and generate a physical map of genomes, genes, or other segments of DNA.
Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503)
Resistance or diminished response of a neoplasm to an antineoplastic agent in humans, animals, or cell or tissue cultures.
Simultaneous resistance to several structurally and functionally distinct drugs.
A genus of gram-positive, facultatively anaerobic, coccoid bacteria. Its organisms occur singly, in pairs, and in tetrads and characteristically divide in more than one plane to form irregular clusters. Natural populations of Staphylococcus are found on the skin and mucous membranes of warm-blooded animals. Some species are opportunistic pathogens of humans and animals.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
The ability of bacteria to resist or to become tolerant to several structurally and functionally distinct drugs simultaneously. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).
Change brought about to an organisms genetic composition by unidirectional transfer (TRANSFECTION; TRANSDUCTION, GENETIC; CONJUGATION, GENETIC, etc.) and incorporation of foreign DNA into prokaryotic or eukaryotic cells by recombination of part or all of that DNA into the cell's genome.
A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.
A gram-positive organism found in the upper respiratory tract, inflammatory exudates, and various body fluids of normal and/or diseased humans and, rarely, domestic animals.
Viruses whose hosts are bacterial cells.
A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.
Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.
In bacteria, a group of metabolically related genes, with a common promoter, whose transcription into a single polycistronic MESSENGER RNA is under the control of an OPERATOR REGION.
The capacity of an organism to defend itself against pathological processes or the agents of those processes. This most often involves innate immunity whereby the organism responds to pathogens in a generic way. The term disease resistance is used most frequently when referring to plants.
Mutagenesis where the mutation is caused by the introduction of foreign DNA sequences into a gene or extragenic sequence. This may occur spontaneously in vivo or be experimentally induced in vivo or in vitro. Proviral DNA insertions into or adjacent to a cellular proto-oncogene can interrupt GENETIC TRANSLATION of the coding sequences or interfere with recognition of regulatory elements and cause unregulated expression of the proto-oncogene resulting in tumor formation.
Potentially pathogenic bacteria found in nasal membranes, skin, hair follicles, and perineum of warm-blooded animals. They may cause a wide range of infections and intoxications.
The force that opposes the flow of BLOOD through a vascular bed. It is equal to the difference in BLOOD PRESSURE across the vascular bed divided by the CARDIAC OUTPUT.
Production of new arrangements of DNA by various mechanisms such as assortment and segregation, CROSSING OVER; GENE CONVERSION; GENETIC TRANSFORMATION; GENETIC CONJUGATION; GENETIC TRANSDUCTION; or mixed infection of viruses.
The ability of viruses to resist or to become tolerant to chemotherapeutic agents or antiviral agents. This resistance is acquired through gene mutation.
In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.
Nonsusceptibility of an organism to the action of penicillins.
Semi-synthetic derivative of penicillin that functions as an orally active broad-spectrum antibiotic.
DNA sequences which are recognized (directly or indirectly) and bound by a DNA-dependent RNA polymerase during the initiation of transcription. Highly conserved sequences within the promoter include the Pribnow box in bacteria and the TATA BOX in eukaryotes.
Nonsusceptibility of bacteria to the action of TETRACYCLINE which inhibits aminoacyl-tRNA binding to the 30S ribosomal subunit during protein synthesis.
The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.

Plasmid replication initiator protein RepD increases the processivity of PcrA DNA helicase. (1/143)

The replication initiator protein RepD encoded by the Staphylococcus chloramphenicol resistance plasmid pC221 stimulates the helicase activity of the Bacillus stearothermophilus PcrA DNA helicase in vitro. This stimulatory effect seems to be specific for PcrA and differs from the stimulatory effect of the Escherichia coli ribosomal protein L3. Whereas L3 stimulates the PcrA helicase activity by promoting co-operative PcrA binding onto its DNA substrate, RepD stimulates the PcrA helicase activity by increasing the processivity of the enzyme and enables PcrA to displace DNA from a nicked substrate. The implication of these results is that PcrA is the helicase recruited into the replisome by RepD during rolling circle replication of plasmids of the pT181 family.  (+info)

Antibiotic resistance of nasopharyngeal isolates of Streptococcus pneumoniae from children in Lesotho. (2/143)

Villages associated with the Lesotho Highlands Development Agency were randomized with a bias in favour of larger villages, and children < 5 years of age from cluster-randomized households in these villages were chosen for the assessment of antibiotic resistance in pneumococci. Children of the same age group attending clinics in the capital, Maseru, were selected for comparison. Nasopharyngeal cultures of Streptococcus pneumoniae from both groups of children were examined for antibiotic resistance and a questionnaire was used to assess risk factors for the acquisition of resistant strains. Carriage of penicillin- and tetracycline-resistant pneumococci was significantly higher among 196 Maseru children compared with 324 rural children (P < 0.05 and P = 0.01, respectively). Maseru children tended to visit clinics at an earlier age compared with their rural counterparts. The rural children were less exposed to antibiotics (P < 0.01), were less frequently hospitalized (P < 0.001), and rarely attended day care centres (P < 0.001). The very low incidence of antibiotic resistance in rural Lesotho and the higher incidence in Maseru are in stark contrast with the much higher frequencies found in the Republic of South Africa, many European countries, and the USA.  (+info)

Pneumococcal and Haemophilus influenzae meningitis in a children's hospital in Ethiopia: serotypes and susceptibility patterns. (3/143)

Streptococcus pneumoniae and Haemophilus influenzae are responsible for most pyogenic meningitis cases in children in Ethiopia. Resistance of S. pneumoniae and H. influenzae to penicillin and chloramphenicol respectively has been reported globally. Resistance has been related to specific serotypes of S. pneumoniae or to beta-lactamase-producing H. influenzae strains. This study describes the serotypes/ serogroups and susceptibility pattern of the two organisms causing meningitis in Ethiopian children. There were 120 cases of meningitis caused by S. pneumoniae (46) and H. influenzae (74) over a period of 3 years (1993-95). Nineteen children died from pneumococcal and 28 from haemophilus meningitis. Penicillin-resistant pneumococcal meningitis (4/8 = 50%) caused a greater mortality rate than penicillin-susceptible pneumococcal meningitis (15/38 = 39%). Common serotypes accounting for 76% of S. pneumoniae were type 14, 19F, 20, 1, 18 and 5; and serotypes 14, 19F and 7 (accounting for 17% of strains) showed intermediate resistance to penicillin G. 97% of the H. influenzae isolates were type b, and in only two cases beta-lactamase-producing. 72% of isolates of the S. pneumoniae we identified belong to serotypes preventable by a 9-valent vaccine. Our study highlights the possibility of resistant pyogenic meningitis in children in Ethiopia due to emerging resistant strains of S. pneumoniae and H. influenzae isolates.  (+info)

Transduction of enteric Escherichia coli isolates with a derivative of Shiga toxin 2-encoding bacteriophage phi3538 isolated from Escherichia coli O157:H7. (4/143)

We investigated the ability of a detoxified derivative of a Shiga toxin 2 (Stx2)-encoding bacteriophage to infect and lysogenize enteric Escherichia coli strains and to develop infectious progeny from such lysogenized strains. The stx(2) gene of the patient E. coli O157:H7 isolate 3538/95 was replaced by the chloramphenicol acetyltransferase (cat) gene from plasmid pACYC184. Phage phi3538(Deltastx(2)::cat) was isolated after induction of E. coli O157:H7 strain 3538/95 with mitomycin. A variety of strains of enteropathogenic E. coli (EPEC), enteroinvasive E. coli (EIEC), Stx-producing E. coli (STEC), enterotoxigenic E. coli (ETEC), enteroaggregative E. coli (EAEC), and E. coli from the physiological stool microflora were infected with phi3538(Deltastx(2)::cat), and plaque formation and lysogenic conversion of wild-type E. coli strains were investigated. With the exception of one EIEC strain, none of the E. coli strains supported the formation of plaques when used as indicators for phi3538(Deltastx(2)::cat). However, 2 of 11 EPEC, 11 of 25 STEC, 2 of 7 EAEC, 1 of 3 EIEC, and 1 of 6 E. coli isolates from the stool microflora of healthy individuals integrated the phage in their chromosomes and expressed resistance to chloramphenicol. Following induction with mitomycin, these lysogenic strains released infectious particles of phi3538(Deltastx(2)::cat) that formed plaques on a lawn of E. coli laboratory strain C600. The results of our study demonstrate that phi3538(Deltastx(2)::cat) was able to infect and lysogenize particular enteric strains of pathogenic and nonpathogenic E. coli and that the lysogens produced infectious phage progeny. Stx-encoding bacteriophages are able to spread stx genes among enteric E. coli strains.  (+info)

Transfer of chloramphenicol-resistant mitochondrial DNA into the chimeric mouse. (5/143)

The mitochondrial DNA (mtDNA) chloramphenicol (CAP)-resistance (CAPR) mutation has been introduced into the tissues of adult mice via female embryonic stem (ES) cells. The endogenous CAP-sensitive (CAPS) mtDNAs were eliminated by treatment of the ES cells with the lipophilic dye Rhodamine-6-G (R-6-G). The ES cells were then fused to enucleated cell cytoplasts prepared from the CAPR mouse cell line 501-1. This procedure converted the ES cell mtDNA from 100% wild-type to 100% mutant. The CAPR ES cells were then injected into blastocysts and viable chimeric mice were isolated. Molecular testing for the CAPR mutant mtDNAs revealed that the percentage of mutant mtDNAs varied from zero to approximately 50% in the tissues analyzed. The highest percentage of mutant mtDNA was found in the kidney in three of the chimeric animals tested. These data suggest that, with improved efficiency, it may be possible to transmit exogenous mtDNA mutants through the mouse germ-line.  (+info)

Increase in incidence of resistance to ampicillin, chloramphenicol and trimethoprim in clinical isolates of Salmonella serotype Typhimurium with investigation of molecular epidemiology and mechanisms of resistance. (6/143)

Antimicrobial resistance patterns of Salmonella serotype Typhimurium isolates obtained during the period 1987-1994 were examined and the molecular epidemiology and the mechanisms of resistance to ampicillin, chloramphenicol and trimethoprim were investigated in 24 strains isolated during 1994. Resistance to ampicillin increased from 18% to 78%, to chloramphenicol from 15% to 78%, to tetracycline from 53% to 89% and to co-trimoxazole from 3% to 37%, whereas resistance to norfloxacin remained at 0%. Of Salmonella serotype Typhimurium strains isolated during 1994, all ampicillin-resistant strains had an MIC > 256 mg/L, except one strain in which the MIC was 64 mg/L. Twelve strains (52%) had a TEM-type beta-lactamase, nine (39%) a CARB-type beta-lactamase and two strains (8%) had an OXA-type beta-lactamase. Chloramphenicol acetyl-transferase activity was detected in only nine (47%) of 19 chloramphenicol resistant strains, whereas all eight trimethoprim-resistant strains produced a dihydrofolate reductase type Ia enzyme. Three different epidemiological groups were defined by either low-frequency restriction analysis of chromosomal DNA and pulsed-field gel electrophoresis or repetitive extragenic palindromic-PCR. The latter technique provided an alternative, rapid and powerful genotyping method for S. Typhimurium. Although quinolones provide a good therapeutic alternative, the multiresistance of S. Typhimurium is of public health concern and it is important to continue surveillance of resistance levels and their mechanisms.  (+info)

Genetic characterization of antimicrobial resistance in Canadian isolates of Salmonella serovar Typhimurium DT104. (7/143)

PCR was used to identify antibiotic resistance determinants in 31 Canadian Salmonella serovar Typhimurium DT104 isolates. Genes encoding resistance to ampicillin (pse1 or blaP1), chloramphenicol (pasppflo-like), streptomycin-spectinomycin (aadA2), sulfonamide (sulI), and tetracycline [tet(G)] were mapped to a 13-kb region of DNA of one isolate. Two copies of sulI were identified and mapped to the 3' end of either pse1 or aadA2 integrons. The two integrons were separated by the pasppflo-like gene and the tet(G) gene. The kanamycin resistance determinant (aphA-1) was present on a 2.0-MDa plasmid (five isolates) or on the chromosome (three isolates).  (+info)

Evolution of chloramphenicol resistance, with emergence of cross-resistance to florfenicol, in bovine Salmonella Typhimurium strains implicates definitive phage type (DT) 104. (8/143)

The prevalence of resistance to florfenicol, a phenicol drug newly introduced in veterinary therapy, was determined in 86 chloramphenicol-resistant Salmonella Typhimurium isolates from cattle collected during 1985-1995. All were highly resistant to chloramphenicol (MICs > or = 128 mg/L) and 38 were simultaneously resistant to florfenicol (MICs >16 mg/L) and to beta-lactam agents, spectinomycin, streptomycin, sulphonamides and tetracyclines. The isolates susceptible to florfenicol harboured the chloramphenicol acetyl transferase gene, cat of type I. All the florfenicol-resistant isolates harboured the floR resistance gene and the characteristic multiple resistance genetic locus, previously characterised in a S. Typhimurium DT104 strain and identified by a multiplex PCR. Plasmid profiles and ribotype patterns were determined for all the isolates. The florfenicol-resistant isolates were grouped into the same ribotyping pattern and presented similar plasmid profiles, whereas the florfenicol-susceptible isolates showed a wider genetic diversity that is usual for S. Typhimurium. Thus, the florfenicol-resistant isolates could represent a clonal cluster, closely related to, if not of DT104 phage type, which appeared in 1989 and is now predominant within chloramphenicol-resistant S. Typhimurium. The multiplex PCR provided a useful tool to survey further evolution of multiresistant S. Typhimurium strains.  (+info)

Chloramphenicol resistance is a type of antibiotic resistance in which bacteria have developed the ability to survive and grow in the presence of the antibiotic Chloramphenicol. This can occur due to genetic mutations or the acquisition of resistance genes from other bacteria through horizontal gene transfer.

There are several mechanisms by which bacteria can become resistant to Chloramphenicol, including:

1. Enzymatic inactivation: Some bacteria produce enzymes that can modify or degrade Chloramphenicol, rendering it ineffective.
2. Efflux pumps: Bacteria may develop efflux pumps that can actively pump Chloramphenicol out of the cell, reducing its intracellular concentration and preventing it from reaching its target site.
3. Target site alteration: Some bacteria may undergo mutations in their ribosomal RNA or proteins, which can prevent Chloramphenicol from binding to its target site and inhibiting protein synthesis.

Chloramphenicol resistance is a significant public health concern because it can limit the effectiveness of this important antibiotic in treating bacterial infections. It is essential to use Chloramphenicol judiciously and follow proper infection control practices to prevent the spread of resistant bacteria.

Chloramphenicol is an antibiotic medication that is used to treat a variety of bacterial infections. It works by inhibiting the ability of bacteria to synthesize proteins, which essential for their growth and survival. This helps to stop the spread of the infection and allows the body's immune system to clear the bacteria from the body.

Chloramphenicol is a broad-spectrum antibiotic, which means that it is effective against many different types of bacteria. It is often used to treat serious infections that have not responded to other antibiotics. However, because of its potential for serious side effects, including bone marrow suppression and gray baby syndrome, chloramphenicol is usually reserved for use in cases where other antibiotics are not effective or are contraindicated.

Chloramphenicol can be given by mouth, injection, or applied directly to the skin in the form of an ointment or cream. It is important to take or use chloramphenicol exactly as directed by a healthcare provider, and to complete the full course of treatment even if symptoms improve before all of the medication has been taken. This helps to ensure that the infection is fully treated and reduces the risk of antibiotic resistance.

Microbial drug resistance is a significant medical issue that refers to the ability of microorganisms (such as bacteria, viruses, fungi, or parasites) to withstand or survive exposure to drugs or medications designed to kill them or limit their growth. This phenomenon has become a major global health concern, particularly in the context of bacterial infections, where it is also known as antibiotic resistance.

Drug resistance arises due to genetic changes in microorganisms that enable them to modify or bypass the effects of antimicrobial agents. These genetic alterations can be caused by mutations or the acquisition of resistance genes through horizontal gene transfer. The resistant microbes then replicate and multiply, forming populations that are increasingly difficult to eradicate with conventional treatments.

The consequences of drug-resistant infections include increased morbidity, mortality, healthcare costs, and the potential for widespread outbreaks. Factors contributing to the emergence and spread of microbial drug resistance include the overuse or misuse of antimicrobials, poor infection control practices, and inadequate surveillance systems.

To address this challenge, it is crucial to promote prudent antibiotic use, strengthen infection prevention and control measures, develop new antimicrobial agents, and invest in research to better understand the mechanisms underlying drug resistance.

Chloramphenicol O-acetyltransferase is an enzyme that is encoded by the cat gene in certain bacteria. This enzyme is responsible for adding acetyl groups to chloramphenicol, which is an antibiotic that inhibits bacterial protein synthesis. When chloramphenicol is acetylated by this enzyme, it becomes inactivated and can no longer bind to the ribosome and prevent bacterial protein synthesis.

Bacteria that are resistant to chloramphenicol often have a plasmid-borne cat gene, which encodes for the production of Chloramphenicol O-acetyltransferase. This enzyme allows the bacteria to survive in the presence of chloramphenicol by rendering it ineffective. The transfer of this plasmid between bacteria can also confer resistance to other susceptible strains.

In summary, Chloramphenicol O-acetyltransferase is an enzyme that inactivates chloramphenicol by adding acetyl groups to it, making it an essential factor in bacterial resistance to this antibiotic.

In the context of medical laboratory reporting, "R factors" refer to a set of values that describe the resistance of certain bacteria to different antibiotics. These factors are typically reported as R1, R2, R3, and so on, where each R factor corresponds to a specific antibiotic or class of antibiotics.

An R factor value of "1" indicates susceptibility to the corresponding antibiotic, while an R factor value of "R" (or "R-", depending on the laboratory's reporting practices) indicates resistance. An intermediate category may also be reported as "I" or "I-", indicating that the bacterium is intermediately sensitive to the antibiotic in question.

It's important to note that R factors are just one piece of information used to guide clinical decision-making around antibiotic therapy, and should be interpreted in conjunction with other factors such as the patient's clinical presentation, the severity of their infection, and any relevant guidelines or recommendations from infectious disease specialists.

Thiamphenicol is an antibiotic that belongs to the class of medications called amphenicols. It works by preventing the growth of bacteria. Thiamphenicol is used to treat various infections caused by bacteria. This medication may also be used to prevent bacterial endocarditis (inflammation of the lining of the heart and valves) in people having certain dental or surgical procedures.

Please note that this definition is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. If you have any questions about your medication, always consult with your healthcare provider.

Extrachromosomal inheritance refers to the transmission of genetic information that occurs outside of the chromosomes, which are the structures in the cell nucleus that typically contain and transmit genetic material. This type of inheritance is relatively rare and can involve various types of genetic elements, such as plasmids or transposons.

In extrachromosomal inheritance, these genetic elements can replicate independently of the chromosomes and be passed on to offspring through mechanisms other than traditional Mendelian inheritance. This can lead to non-Mendelian patterns of inheritance, where traits do not follow the expected dominant or recessive patterns.

One example of extrachromosomal inheritance is the transmission of mitochondrial DNA (mtDNA), which occurs in the cytoplasm of the cell rather than on the chromosomes. Mitochondria are organelles that produce energy for the cell, and they contain their own small circular genome that is inherited maternally. Mutations in mtDNA can lead to a variety of genetic disorders, including mitochondrial diseases.

Overall, extrachromosomal inheritance is an important area of study in genetics, as it can help researchers better understand the complex ways in which genetic information is transmitted and expressed in living organisms.

A plasmid is a small, circular, double-stranded DNA molecule that is separate from the chromosomal DNA of a bacterium or other organism. Plasmids are typically not essential for the survival of the organism, but they can confer beneficial traits such as antibiotic resistance or the ability to degrade certain types of pollutants.

Plasmids are capable of replicating independently of the chromosomal DNA and can be transferred between bacteria through a process called conjugation. They often contain genes that provide resistance to antibiotics, heavy metals, and other environmental stressors. Plasmids have also been engineered for use in molecular biology as cloning vectors, allowing scientists to replicate and manipulate specific DNA sequences.

Plasmids are important tools in genetic engineering and biotechnology because they can be easily manipulated and transferred between organisms. They have been used to produce vaccines, diagnostic tests, and genetically modified organisms (GMOs) for various applications, including agriculture, medicine, and industry.

Acetyltransferases are a type of enzyme that facilitates the transfer of an acetyl group (a chemical group consisting of an acetyl molecule, which is made up of carbon, hydrogen, and oxygen atoms) from a donor molecule to a recipient molecule. This transfer of an acetyl group can modify the function or activity of the recipient molecule.

In the context of biology and medicine, acetyltransferases are important for various cellular processes, including gene expression, DNA replication, and protein function. For example, histone acetyltransferases (HATs) are a type of acetyltransferase that add an acetyl group to the histone proteins around which DNA is wound. This modification can alter the structure of the chromatin, making certain genes more or less accessible for transcription, and thereby influencing gene expression.

Abnormal regulation of acetyltransferases has been implicated in various diseases, including cancer, neurodegenerative disorders, and infectious diseases. Therefore, understanding the function and regulation of these enzymes is an important area of research in biomedicine.

Genetic conjugation is a type of genetic transfer that occurs between bacterial cells. It involves the process of one bacterium (the donor) transferring a piece of its DNA to another bacterium (the recipient) through direct contact or via a bridge-like connection called a pilus. This transferred DNA may contain genes that provide the recipient cell with new traits, such as antibiotic resistance or virulence factors, which can make the bacteria more harmful or difficult to treat. Genetic conjugation is an important mechanism for the spread of antibiotic resistance and other traits among bacterial populations.

'Escherichia coli' (E. coli) is a type of gram-negative, facultatively anaerobic, rod-shaped bacterium that commonly inhabits the intestinal tract of humans and warm-blooded animals. It is a member of the family Enterobacteriaceae and one of the most well-studied prokaryotic model organisms in molecular biology.

While most E. coli strains are harmless and even beneficial to their hosts, some serotypes can cause various forms of gastrointestinal and extraintestinal illnesses in humans and animals. These pathogenic strains possess virulence factors that enable them to colonize and damage host tissues, leading to diseases such as diarrhea, urinary tract infections, pneumonia, and sepsis.

E. coli is a versatile organism with remarkable genetic diversity, which allows it to adapt to various environmental niches. It can be found in water, soil, food, and various man-made environments, making it an essential indicator of fecal contamination and a common cause of foodborne illnesses. The study of E. coli has contributed significantly to our understanding of fundamental biological processes, including DNA replication, gene regulation, and protein synthesis.

Bacterial DNA refers to the genetic material found in bacteria. It is composed of a double-stranded helix containing four nucleotide bases - adenine (A), thymine (T), guanine (G), and cytosine (C) - that are linked together by phosphodiester bonds. The sequence of these bases in the DNA molecule carries the genetic information necessary for the growth, development, and reproduction of bacteria.

Bacterial DNA is circular in most bacterial species, although some have linear chromosomes. In addition to the main chromosome, many bacteria also contain small circular pieces of DNA called plasmids that can carry additional genes and provide resistance to antibiotics or other environmental stressors.

Unlike eukaryotic cells, which have their DNA enclosed within a nucleus, bacterial DNA is present in the cytoplasm of the cell, where it is in direct contact with the cell's metabolic machinery. This allows for rapid gene expression and regulation in response to changing environmental conditions.

Bacterial transformation is a natural process by which exogenous DNA is taken up and incorporated into the genome of a bacterial cell. This process was first discovered in 1928 by Frederick Griffith, who observed that dead virulent bacteria could transfer genetic material to live avirulent bacteria, thereby conferring new properties such as virulence to the recipient cells.

The uptake of DNA by bacterial cells typically occurs through a process called "competence," which can be either naturally induced under certain environmental conditions or artificially induced in the laboratory using various methods. Once inside the cell, the exogenous DNA may undergo recombination with the host genome, resulting in the acquisition of new genes or the alteration of existing ones.

Bacterial transformation has important implications for both basic research and biotechnology. It is a powerful tool for studying gene function and for engineering bacteria with novel properties, such as the ability to produce valuable proteins or degrade environmental pollutants. However, it also poses potential risks in the context of genetic engineering and biocontainment, as transformed bacteria may be able to transfer their newly acquired genes to other organisms in the environment.

A bacterial gene is a segment of DNA (or RNA in some viruses) that contains the genetic information necessary for the synthesis of a functional bacterial protein or RNA molecule. These genes are responsible for encoding various characteristics and functions of bacteria such as metabolism, reproduction, and resistance to antibiotics. They can be transmitted between bacteria through horizontal gene transfer mechanisms like conjugation, transformation, and transduction. Bacterial genes are often organized into operons, which are clusters of genes that are transcribed together as a single mRNA molecule.

It's important to note that the term "bacterial gene" is used to describe genetic elements found in bacteria, but not all genetic elements in bacteria are considered genes. For example, some DNA sequences may not encode functional products and are therefore not considered genes. Additionally, some bacterial genes may be plasmid-borne or phage-borne, rather than being located on the bacterial chromosome.

Streptomycin is an antibiotic drug derived from the actinobacterium Streptomyces griseus. It belongs to the class of aminoglycosides and works by binding to the 30S subunit of the bacterial ribosome, thereby inhibiting protein synthesis and leading to bacterial death.

Streptomycin is primarily used to treat a variety of infections caused by gram-negative and gram-positive bacteria, including tuberculosis, brucellosis, plague, tularemia, and certain types of bacterial endocarditis. It is also used as part of combination therapy for the treatment of multidrug-resistant tuberculosis (MDR-TB).

Like other aminoglycosides, streptomycin has a narrow therapeutic index and can cause ototoxicity (hearing loss) and nephrotoxicity (kidney damage) with prolonged use or high doses. Therefore, its use is typically limited to cases where other antibiotics are ineffective or contraindicated.

It's important to note that the use of streptomycin requires careful monitoring of drug levels and kidney function, as well as regular audiometric testing to detect any potential hearing loss.

Tetracycline is a broad-spectrum antibiotic, which is used to treat various bacterial infections. It works by preventing the growth and multiplication of bacteria. It is a part of the tetracycline class of antibiotics, which also includes doxycycline, minocycline, and others.

Tetracycline is effective against a wide range of gram-positive and gram-negative bacteria, as well as some atypical organisms such as rickettsia, chlamydia, mycoplasma, and spirochetes. It is commonly used to treat respiratory infections, skin infections, urinary tract infections, sexually transmitted diseases, and other bacterial infections.

Tetracycline is available in various forms, including tablets, capsules, and liquid solutions. It should be taken orally with a full glass of water, and it is recommended to take it on an empty stomach, at least one hour before or two hours after meals. The drug can cause tooth discoloration in children under the age of 8, so it is generally not recommended for use in this population.

Like all antibiotics, tetracycline should be used only to treat bacterial infections and not viral infections, such as the common cold or flu. Overuse or misuse of antibiotics can lead to antibiotic resistance, which makes it harder to treat infections in the future.

Bacterial drug resistance is a type of antimicrobial resistance that occurs when bacteria evolve the ability to survive and reproduce in the presence of drugs (such as antibiotics) that would normally kill them or inhibit their growth. This can happen due to various mechanisms, including genetic mutations or the acquisition of resistance genes from other bacteria.

As a result, bacterial infections may become more difficult to treat, requiring higher doses of medication, alternative drugs, or longer treatment courses. In some cases, drug-resistant infections can lead to serious health complications, increased healthcare costs, and higher mortality rates.

Examples of bacterial drug resistance include methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococci (VRE), and multidrug-resistant tuberculosis (MDR-TB). Preventing the spread of bacterial drug resistance is crucial for maintaining effective treatments for infectious diseases.

Anti-bacterial agents, also known as antibiotics, are a type of medication used to treat infections caused by bacteria. These agents work by either killing the bacteria or inhibiting their growth and reproduction. There are several different classes of anti-bacterial agents, including penicillins, cephalosporins, fluoroquinolones, macrolides, and tetracyclines, among others. Each class of antibiotic has a specific mechanism of action and is used to treat certain types of bacterial infections. It's important to note that anti-bacterial agents are not effective against viral infections, such as the common cold or flu. Misuse and overuse of antibiotics can lead to antibiotic resistance, which is a significant global health concern.

Microbial sensitivity tests, also known as antibiotic susceptibility tests (ASTs) or bacterial susceptibility tests, are laboratory procedures used to determine the effectiveness of various antimicrobial agents against specific microorganisms isolated from a patient's infection. These tests help healthcare providers identify which antibiotics will be most effective in treating an infection and which ones should be avoided due to resistance. The results of these tests can guide appropriate antibiotic therapy, minimize the potential for antibiotic resistance, improve clinical outcomes, and reduce unnecessary side effects or toxicity from ineffective antimicrobials.

There are several methods for performing microbial sensitivity tests, including:

1. Disk diffusion method (Kirby-Bauer test): A standardized paper disk containing a predetermined amount of an antibiotic is placed on an agar plate that has been inoculated with the isolated microorganism. After incubation, the zone of inhibition around the disk is measured to determine the susceptibility or resistance of the organism to that particular antibiotic.
2. Broth dilution method: A series of tubes or wells containing decreasing concentrations of an antimicrobial agent are inoculated with a standardized microbial suspension. After incubation, the minimum inhibitory concentration (MIC) is determined by observing the lowest concentration of the antibiotic that prevents visible growth of the organism.
3. Automated systems: These use sophisticated technology to perform both disk diffusion and broth dilution methods automatically, providing rapid and accurate results for a wide range of microorganisms and antimicrobial agents.

The interpretation of microbial sensitivity test results should be done cautiously, considering factors such as the site of infection, pharmacokinetics and pharmacodynamics of the antibiotic, potential toxicity, and local resistance patterns. Regular monitoring of susceptibility patterns and ongoing antimicrobial stewardship programs are essential to ensure optimal use of these tests and to minimize the development of antibiotic resistance.

Bacterial chromosomes are typically circular, double-stranded DNA molecules that contain the genetic material of bacteria. Unlike eukaryotic cells, which have their DNA housed within a nucleus, bacterial chromosomes are located in the cytoplasm of the cell, often associated with the bacterial nucleoid.

Bacterial chromosomes can vary in size and structure among different species, but they typically contain all of the genetic information necessary for the survival and reproduction of the organism. They may also contain plasmids, which are smaller circular DNA molecules that can carry additional genes and can be transferred between bacteria through a process called conjugation.

One important feature of bacterial chromosomes is their ability to replicate rapidly, allowing bacteria to divide quickly and reproduce in large numbers. The replication of the bacterial chromosome begins at a specific origin point and proceeds in opposite directions until the entire chromosome has been copied. This process is tightly regulated and coordinated with cell division to ensure that each daughter cell receives a complete copy of the genetic material.

Overall, the study of bacterial chromosomes is an important area of research in microbiology, as understanding their structure and function can provide insights into bacterial genetics, evolution, and pathogenesis.

A base sequence in the context of molecular biology refers to the specific order of nucleotides in a DNA or RNA molecule. In DNA, these nucleotides are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) takes the place of thymine. The base sequence contains genetic information that is transcribed into RNA and ultimately translated into proteins. It is the exact order of these bases that determines the genetic code and thus the function of the DNA or RNA molecule.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

Molecular cloning is a laboratory technique used to create multiple copies of a specific DNA sequence. This process involves several steps:

1. Isolation: The first step in molecular cloning is to isolate the DNA sequence of interest from the rest of the genomic DNA. This can be done using various methods such as PCR (polymerase chain reaction), restriction enzymes, or hybridization.
2. Vector construction: Once the DNA sequence of interest has been isolated, it must be inserted into a vector, which is a small circular DNA molecule that can replicate independently in a host cell. Common vectors used in molecular cloning include plasmids and phages.
3. Transformation: The constructed vector is then introduced into a host cell, usually a bacterial or yeast cell, through a process called transformation. This can be done using various methods such as electroporation or chemical transformation.
4. Selection: After transformation, the host cells are grown in selective media that allow only those cells containing the vector to grow. This ensures that the DNA sequence of interest has been successfully cloned into the vector.
5. Amplification: Once the host cells have been selected, they can be grown in large quantities to amplify the number of copies of the cloned DNA sequence.

Molecular cloning is a powerful tool in molecular biology and has numerous applications, including the production of recombinant proteins, gene therapy, functional analysis of genes, and genetic engineering.

DNA transposable elements, also known as transposons or jumping genes, are mobile genetic elements that can change their position within a genome. They are composed of DNA sequences that include genes encoding the enzymes required for their own movement (transposase) and regulatory elements. When activated, the transposase recognizes specific sequences at the ends of the element and catalyzes the excision and reintegration of the transposable element into a new location in the genome. This process can lead to genetic variation, as the insertion of a transposable element can disrupt the function of nearby genes or create new combinations of gene regulatory elements. Transposable elements are widespread in both prokaryotic and eukaryotic genomes and are thought to play a significant role in genome evolution.

'Bacillus subtilis' is a gram-positive, rod-shaped bacterium that is commonly found in soil and vegetation. It is a facultative anaerobe, meaning it can grow with or without oxygen. This bacterium is known for its ability to form durable endospores during unfavorable conditions, which allows it to survive in harsh environments for long periods of time.

'Bacillus subtilis' has been widely studied as a model organism in microbiology and molecular biology due to its genetic tractability and rapid growth. It is also used in various industrial applications, such as the production of enzymes, antibiotics, and other bioproducts.

Although 'Bacillus subtilis' is generally considered non-pathogenic, there have been rare cases of infection in immunocompromised individuals. It is important to note that this bacterium should not be confused with other pathogenic species within the genus Bacillus, such as B. anthracis (causative agent of anthrax) or B. cereus (a foodborne pathogen).

Drug resistance, also known as antimicrobial resistance, is the ability of a microorganism (such as bacteria, viruses, fungi, or parasites) to withstand the effects of a drug that was originally designed to inhibit or kill it. This occurs when the microorganism undergoes genetic changes that allow it to survive in the presence of the drug. As a result, the drug becomes less effective or even completely ineffective at treating infections caused by these resistant organisms.

Drug resistance can develop through various mechanisms, including mutations in the genes responsible for producing the target protein of the drug, alteration of the drug's target site, modification or destruction of the drug by enzymes produced by the microorganism, and active efflux of the drug from the cell.

The emergence and spread of drug-resistant microorganisms pose significant challenges in medical treatment, as they can lead to increased morbidity, mortality, and healthcare costs. The overuse and misuse of antimicrobial agents, as well as poor infection control practices, contribute to the development and dissemination of drug-resistant strains. To address this issue, it is crucial to promote prudent use of antimicrobials, enhance surveillance and monitoring of resistance patterns, invest in research and development of new antimicrobial agents, and strengthen infection prevention and control measures.

Erythromycin is a type of antibiotic known as a macrolide, which is used to treat various types of bacterial infections. It works by inhibiting the bacteria's ability to produce proteins, which are necessary for the bacteria to survive and multiply. Erythromycin is often used to treat respiratory tract infections, skin infections, and sexually transmitted diseases. It may also be used to prevent endocarditis (inflammation of the lining of the heart) in people at risk of this condition.

Erythromycin is generally considered safe for most people, but it can cause side effects such as nausea, vomiting, and diarrhea. It may also interact with other medications, so it's important to tell your doctor about all the drugs you are taking before starting erythromycin.

Like all antibiotics, erythromycin should only be used to treat bacterial infections, as it is not effective against viral infections such as the common cold or flu. Overuse of antibiotics can lead to antibiotic resistance, which makes it harder to treat infections in the future.

A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.

Bacterial proteins are a type of protein that are produced by bacteria as part of their structural or functional components. These proteins can be involved in various cellular processes, such as metabolism, DNA replication, transcription, and translation. They can also play a role in bacterial pathogenesis, helping the bacteria to evade the host's immune system, acquire nutrients, and multiply within the host.

Bacterial proteins can be classified into different categories based on their function, such as:

1. Enzymes: Proteins that catalyze chemical reactions in the bacterial cell.
2. Structural proteins: Proteins that provide structural support and maintain the shape of the bacterial cell.
3. Signaling proteins: Proteins that help bacteria to communicate with each other and coordinate their behavior.
4. Transport proteins: Proteins that facilitate the movement of molecules across the bacterial cell membrane.
5. Toxins: Proteins that are produced by pathogenic bacteria to damage host cells and promote infection.
6. Surface proteins: Proteins that are located on the surface of the bacterial cell and interact with the environment or host cells.

Understanding the structure and function of bacterial proteins is important for developing new antibiotics, vaccines, and other therapeutic strategies to combat bacterial infections.

'Clostridium perfringens' is a type of Gram-positive, rod-shaped, spore-forming bacterium that is commonly found in the environment, including in soil, decaying vegetation, and the intestines of humans and animals. It is a major cause of foodborne illness worldwide, producing several toxins that can lead to symptoms such as diarrhea, abdominal cramps, nausea, and vomiting.

The bacterium can contaminate food during preparation or storage, particularly meat and poultry products. When ingested, the spores of C. perfringens can germinate and produce large numbers of toxin-producing cells in the intestines, leading to food poisoning. The most common form of C. perfringens food poisoning is characterized by symptoms that appear within 6 to 24 hours after ingestion and last for less than 24 hours.

In addition to foodborne illness, C. perfringens can also cause other types of infections, such as gas gangrene, a serious condition that can occur when the bacterium infects a wound and produces toxins that damage surrounding tissues. Gas gangrene is a medical emergency that requires prompt treatment with antibiotics and surgical debridement or amputation of affected tissue.

Prevention measures for C. perfringens food poisoning include proper cooking, handling, and storage of food, as well as rapid cooling of cooked foods to prevent the growth of the bacterium.

Haemophilus influenzae is a gram-negative, coccobacillary bacterium that can cause a variety of infectious diseases in humans. It is part of the normal respiratory flora but can become pathogenic under certain circumstances. The bacteria are named after their initial discovery in 1892 by Richard Pfeiffer during an influenza pandemic, although they are not the causative agent of influenza.

There are six main serotypes (a-f) based on the polysaccharide capsule surrounding the bacterium, with type b (Hib) being the most virulent and invasive. Hib can cause severe invasive diseases such as meningitis, pneumonia, epiglottitis, and sepsis, particularly in children under 5 years of age. The introduction of the Hib conjugate vaccine has significantly reduced the incidence of these invasive diseases.

Non-typeable Haemophilus influenzae (NTHi) strains lack a capsule and are responsible for non-invasive respiratory tract infections, such as otitis media, sinusitis, and exacerbations of chronic obstructive pulmonary disease (COPD). NTHi can also cause invasive diseases but at lower frequency compared to Hib.

Proper diagnosis and antibiotic susceptibility testing are crucial for effective treatment, as Haemophilus influenzae strains may display resistance to certain antibiotics.

DNA restriction enzymes, also known as restriction endonucleases, are a type of enzyme that cut double-stranded DNA at specific recognition sites. These enzymes are produced by bacteria and archaea as a defense mechanism against foreign DNA, such as that found in bacteriophages (viruses that infect bacteria).

Restriction enzymes recognize specific sequences of nucleotides (the building blocks of DNA) and cleave the phosphodiester bonds between them. The recognition sites for these enzymes are usually palindromic, meaning that the sequence reads the same in both directions when facing the opposite strands of DNA.

Restriction enzymes are widely used in molecular biology research for various applications such as genetic engineering, genome mapping, and DNA fingerprinting. They allow scientists to cut DNA at specific sites, creating precise fragments that can be manipulated and analyzed. The use of restriction enzymes has been instrumental in the development of recombinant DNA technology and the Human Genome Project.

Chromosome mapping, also known as physical mapping, is the process of determining the location and order of specific genes or genetic markers on a chromosome. This is typically done by using various laboratory techniques to identify landmarks along the chromosome, such as restriction enzyme cutting sites or patterns of DNA sequence repeats. The resulting map provides important information about the organization and structure of the genome, and can be used for a variety of purposes, including identifying the location of genes associated with genetic diseases, studying evolutionary relationships between organisms, and developing genetic markers for use in breeding or forensic applications.

Circular DNA is a type of DNA molecule that forms a closed loop, rather than the linear double helix structure commonly associated with DNA. This type of DNA is found in some viruses, plasmids (small extrachromosomal DNA molecules found in bacteria), and mitochondria and chloroplasts (organelles found in plant and animal cells).

Circular DNA is characterized by the absence of telomeres, which are the protective caps found on linear chromosomes. Instead, circular DNA has a specific sequence where the two ends join together, known as the origin of replication and the replication terminus. This structure allows for the DNA to be replicated efficiently and compactly within the cell.

Because of its circular nature, circular DNA is more resistant to degradation by enzymes that cut linear DNA, making it more stable in certain environments. Additionally, the ability to easily manipulate and clone circular DNA has made it a valuable tool in molecular biology and genetic engineering.

Genetic transduction is a process in molecular biology that describes the transfer of genetic material from one bacterium to another by a viral vector called a bacteriophage (or phage). In this process, the phage infects one bacterium and incorporates a portion of the bacterial DNA into its own genetic material. When the phage then infects a second bacterium, it can transfer the incorporated bacterial DNA to the new host. This can result in the horizontal gene transfer (HGT) of traits such as antibiotic resistance or virulence factors between bacteria.

There are two main types of transduction: generalized and specialized. In generalized transduction, any portion of the bacterial genome can be packaged into the phage particle, leading to a random assortment of genetic material being transferred. In specialized transduction, only specific genes near the site where the phage integrates into the bacterial chromosome are consistently transferred.

It's important to note that genetic transduction is not to be confused with transformation or conjugation, which are other mechanisms of HGT in bacteria.

Restriction mapping is a technique used in molecular biology to identify the location and arrangement of specific restriction endonuclease recognition sites within a DNA molecule. Restriction endonucleases are enzymes that cut double-stranded DNA at specific sequences, producing fragments of various lengths. By digesting the DNA with different combinations of these enzymes and analyzing the resulting fragment sizes through techniques such as agarose gel electrophoresis, researchers can generate a restriction map - a visual representation of the locations and distances between recognition sites on the DNA molecule. This information is crucial for various applications, including cloning, genome analysis, and genetic engineering.

Nucleic acid hybridization is a process in molecular biology where two single-stranded nucleic acids (DNA, RNA) with complementary sequences pair together to form a double-stranded molecule through hydrogen bonding. The strands can be from the same type of nucleic acid or different types (i.e., DNA-RNA or DNA-cDNA). This process is commonly used in various laboratory techniques, such as Southern blotting, Northern blotting, polymerase chain reaction (PCR), and microarray analysis, to detect, isolate, and analyze specific nucleic acid sequences. The hybridization temperature and conditions are critical to ensure the specificity of the interaction between the two strands.

Drug resistance in neoplasms (also known as cancer drug resistance) refers to the ability of cancer cells to withstand the effects of chemotherapeutic agents or medications designed to kill or inhibit the growth of cancer cells. This can occur due to various mechanisms, including changes in the cancer cell's genetic makeup, alterations in drug targets, increased activity of drug efflux pumps, and activation of survival pathways.

Drug resistance can be intrinsic (present at the beginning of treatment) or acquired (developed during the course of treatment). It is a significant challenge in cancer therapy as it often leads to reduced treatment effectiveness, disease progression, and poor patient outcomes. Strategies to overcome drug resistance include the use of combination therapies, development of new drugs that target different mechanisms, and personalized medicine approaches that consider individual patient and tumor characteristics.

"Multiple drug resistance" (MDR) is a term used in medicine to describe the condition where a patient's infection becomes resistant to multiple antimicrobial drugs. This means that the bacteria, virus, fungus or parasite that is causing the infection has developed the ability to survive and multiply despite being exposed to medications that were originally designed to kill or inhibit its growth.

In particular, MDR occurs when an organism becomes resistant to at least one drug in three or more antimicrobial categories. This can happen due to genetic changes in the microorganism that allow it to survive in the presence of these drugs. The development of MDR is a significant concern for public health because it limits treatment options and can make infections harder, if not impossible, to treat.

MDR can develop through several mechanisms, including mutations in the genes that encode drug targets or enzymes involved in drug metabolism, as well as the acquisition of genetic elements such as plasmids and transposons that carry resistance genes. The overuse and misuse of antimicrobial drugs are major drivers of MDR, as they create selective pressure for the emergence and spread of resistant strains.

MDR infections can occur in various settings, including hospitals, long-term care facilities, and communities. They can affect people of all ages and backgrounds, although certain populations may be at higher risk, such as those with weakened immune systems or chronic medical conditions. Preventing the spread of MDR requires a multifaceted approach that includes surveillance, infection control, antimicrobial stewardship, and research into new therapies and diagnostics.

Staphylococcus is a genus of Gram-positive, facultatively anaerobic bacteria that are commonly found on the skin and mucous membranes of humans and other animals. Many species of Staphylococcus can cause infections in humans, but the most notable is Staphylococcus aureus, which is responsible for a wide range of illnesses, from minor skin infections to life-threatening conditions such as pneumonia, endocarditis, and sepsis.

Staphylococcus species are non-motile, non-spore forming, and typically occur in grape-like clusters when viewed under a microscope. They can be coagulase-positive or coagulase-negative, with S. aureus being the most well-known coagulase-positive species. Coagulase is an enzyme that causes the clotting of plasma, and its presence is often used to differentiate S. aureus from other Staphylococcus species.

These bacteria are resistant to many commonly used antibiotics, including penicillin, due to the production of beta-lactamases. Methicillin-resistant Staphylococcus aureus (MRSA) is a particularly problematic strain that has developed resistance to multiple antibiotics and can cause severe, difficult-to-treat infections.

Proper hand hygiene, use of personal protective equipment, and environmental cleaning are crucial measures for preventing the spread of Staphylococcus in healthcare settings and the community.

An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.

Multiple bacterial drug resistance (MDR) is a medical term that refers to the resistance of multiple strains of bacteria to several antibiotics or antimicrobial agents. This means that these bacteria have developed mechanisms that enable them to survive and multiply despite being exposed to drugs that were previously effective in treating infections caused by them.

MDR is a significant public health concern because it limits the treatment options available for bacterial infections, making them more difficult and expensive to treat. In some cases, MDR bacteria may cause severe or life-threatening infections that are resistant to all available antibiotics, leaving doctors with few or no effective therapeutic options.

MDR can arise due to various mechanisms, including the production of enzymes that inactivate antibiotics, changes in bacterial cell membrane permeability that prevent antibiotics from entering the bacteria, and the development of efflux pumps that expel antibiotics out of the bacteria. The misuse or overuse of antibiotics is a significant contributor to the emergence and spread of MDR bacteria.

Preventing and controlling the spread of MDR bacteria requires a multifaceted approach, including the judicious use of antibiotics, infection control measures, surveillance, and research into new antimicrobial agents.

Genetic transformation is the process by which an organism's genetic material is altered or modified, typically through the introduction of foreign DNA. This can be achieved through various techniques such as:

* Gene transfer using vectors like plasmids, phages, or artificial chromosomes
* Direct uptake of naked DNA using methods like electroporation or chemically-mediated transfection
* Use of genome editing tools like CRISPR-Cas9 to introduce precise changes into the organism's genome.

The introduced DNA may come from another individual of the same species (cisgenic), from a different species (transgenic), or even be synthetically designed. The goal of genetic transformation is often to introduce new traits, functions, or characteristics that do not exist naturally in the organism, or to correct genetic defects.

This technique has broad applications in various fields, including molecular biology, biotechnology, and medical research, where it can be used to study gene function, develop genetically modified organisms (GMOs), create cell lines for drug screening, and even potentially treat genetic diseases through gene therapy.

A gene is a specific sequence of nucleotides in DNA that carries genetic information. Genes are the fundamental units of heredity and are responsible for the development and function of all living organisms. They code for proteins or RNA molecules, which carry out various functions within cells and are essential for the structure, function, and regulation of the body's tissues and organs.

Each gene has a specific location on a chromosome, and each person inherits two copies of every gene, one from each parent. Variations in the sequence of nucleotides in a gene can lead to differences in traits between individuals, including physical characteristics, susceptibility to disease, and responses to environmental factors.

Medical genetics is the study of genes and their role in health and disease. It involves understanding how genes contribute to the development and progression of various medical conditions, as well as identifying genetic risk factors and developing strategies for prevention, diagnosis, and treatment.

Streptococcus pneumoniae, also known as the pneumococcus, is a gram-positive, alpha-hemolytic bacterium frequently found in the upper respiratory tract of healthy individuals. It is a leading cause of community-acquired pneumonia and can also cause other infectious diseases such as otitis media (ear infection), sinusitis, meningitis, and bacteremia (bloodstream infection). The bacteria are encapsulated, and there are over 90 serotypes based on variations in the capsular polysaccharide. Some serotypes are more virulent or invasive than others, and the polysaccharide composition is crucial for vaccine development. S. pneumoniae infection can be treated with antibiotics, but the emergence of drug-resistant strains has become a significant global health concern.

Bacteriophages, often simply called phages, are viruses that infect and replicate within bacteria. They consist of a protein coat, called the capsid, that encases the genetic material, which can be either DNA or RNA. Bacteriophages are highly specific, meaning they only infect certain types of bacteria, and they reproduce by hijacking the bacterial cell's machinery to produce more viruses.

Once a phage infects a bacterium, it can either replicate its genetic material and create new phages (lytic cycle), or integrate its genetic material into the bacterial chromosome and replicate along with the bacterium (lysogenic cycle). In the lytic cycle, the newly formed phages are released by lysing, or breaking open, the bacterial cell.

Bacteriophages play a crucial role in shaping microbial communities and have been studied as potential alternatives to antibiotics for treating bacterial infections.

DNA Sequence Analysis is the systematic determination of the order of nucleotides in a DNA molecule. It is a critical component of modern molecular biology, genetics, and genetic engineering. The process involves determining the exact order of the four nucleotide bases - adenine (A), guanine (G), cytosine (C), and thymine (T) - in a DNA molecule or fragment. This information is used in various applications such as identifying gene mutations, studying evolutionary relationships, developing molecular markers for breeding, and diagnosing genetic diseases.

The process of DNA Sequence Analysis typically involves several steps, including DNA extraction, PCR amplification (if necessary), purification, sequencing reaction, and electrophoresis. The resulting data is then analyzed using specialized software to determine the exact sequence of nucleotides.

In recent years, high-throughput DNA sequencing technologies have revolutionized the field of genomics, enabling the rapid and cost-effective sequencing of entire genomes. This has led to an explosion of genomic data and new insights into the genetic basis of many diseases and traits.

Culture media is a substance that is used to support the growth of microorganisms or cells in an artificial environment, such as a petri dish or test tube. It typically contains nutrients and other factors that are necessary for the growth and survival of the organisms being cultured. There are many different types of culture media, each with its own specific formulation and intended use. Some common examples include blood agar, which is used to culture bacteria; Sabouraud dextrose agar, which is used to culture fungi; and Eagle's minimum essential medium, which is used to culture animal cells.

An operon is a genetic unit in prokaryotic organisms (like bacteria) consisting of a cluster of genes that are transcribed together as a single mRNA molecule, which then undergoes translation to produce multiple proteins. This genetic organization allows for the coordinated regulation of genes that are involved in the same metabolic pathway or functional process. The unit typically includes promoter and operator regions that control the transcription of the operon, as well as structural genes encoding the proteins. Operons were first discovered in bacteria, but similar genetic organizations have been found in some eukaryotic organisms, such as yeast.

Disease resistance, in a medical context, refers to the inherent or acquired ability of an organism to withstand or limit infection by a pathogen, such as bacteria, viruses, fungi, or parasites. This resistance can be due to various factors including the presence of physical barriers (e.g., intact skin), chemical barriers (e.g., stomach acid), and immune responses that recognize and eliminate the pathogen.

Inherited disease resistance is often determined by genetics, where certain genetic variations can make an individual more or less susceptible to a particular infection. For example, some people are naturally resistant to certain diseases due to genetic factors that prevent the pathogen from infecting their cells or replicating within them.

Acquired disease resistance can occur through exposure to a pathogen, which triggers an immune response that confers immunity or resistance to future infections by the same pathogen. This is the basis of vaccination, where a weakened or dead form of a pathogen is introduced into the body to stimulate an immune response without causing disease.

Overall, disease resistance is an important factor in maintaining health and preventing the spread of infectious diseases.

Insertional mutagenesis is a process of introducing new genetic material into an organism's genome at a specific location, which can result in a change or disruption of the function of the gene at that site. This technique is often used in molecular biology research to study gene function and regulation. The introduction of the foreign DNA is typically accomplished through the use of mobile genetic elements, such as transposons or viruses, which are capable of inserting themselves into the genome.

The insertion of the new genetic material can lead to a loss or gain of function in the affected gene, resulting in a mutation. This type of mutagenesis is called "insertional" because the mutation is caused by the insertion of foreign DNA into the genome. The effects of insertional mutagenesis can range from subtle changes in gene expression to the complete inactivation of a gene.

This technique has been widely used in genetic research, including the study of developmental biology, cancer, and genetic diseases. It is also used in the development of genetically modified organisms (GMOs) for agricultural and industrial applications.

Staphylococcus aureus is a type of gram-positive, round (coccal) bacterium that is commonly found on the skin and mucous membranes of warm-blooded animals and humans. It is a facultative anaerobe, which means it can grow in the presence or absence of oxygen.

Staphylococcus aureus is known to cause a wide range of infections, from mild skin infections such as pimples, impetigo, and furuncles (boils) to more severe and potentially life-threatening infections such as pneumonia, endocarditis, osteomyelitis, and sepsis. It can also cause food poisoning and toxic shock syndrome.

The bacterium is often resistant to multiple antibiotics, including methicillin, which has led to the emergence of methicillin-resistant Staphylococcus aureus (MRSA) strains that are difficult to treat. Proper hand hygiene and infection control practices are critical in preventing the spread of Staphylococcus aureus and MRSA.

Vascular resistance is a measure of the opposition to blood flow within a vessel or a group of vessels, typically expressed in units of mmHg/(mL/min) or sometimes as dynes*sec/cm^5. It is determined by the diameter and length of the vessels, as well as the viscosity of the blood flowing through them. In general, a decrease in vessel diameter, an increase in vessel length, or an increase in blood viscosity will result in an increase in vascular resistance, while an increase in vessel diameter, a decrease in vessel length, or a decrease in blood viscosity will result in a decrease in vascular resistance. Vascular resistance is an important concept in the study of circulation and cardiovascular physiology because it plays a key role in determining blood pressure and blood flow within the body.

Genetic recombination is the process by which genetic material is exchanged between two similar or identical molecules of DNA during meiosis, resulting in new combinations of genes on each chromosome. This exchange occurs during crossover, where segments of DNA are swapped between non-sister homologous chromatids, creating genetic diversity among the offspring. It is a crucial mechanism for generating genetic variability and facilitating evolutionary change within populations. Additionally, recombination also plays an essential role in DNA repair processes through mechanisms such as homologous recombinational repair (HRR) and non-homologous end joining (NHEJ).

Drug resistance, viral, refers to the ability of a virus to continue replicating in the presence of antiviral drugs that are designed to inhibit or stop its growth. This occurs when the virus mutates and changes its genetic makeup in such a way that the drug can no longer effectively bind to and inhibit the function of its target protein, allowing the virus to continue infecting host cells and causing disease.

Viral drug resistance can develop due to several factors, including:

1. Mutations in the viral genome that alter the structure or function of the drug's target protein.
2. Changes in the expression levels or location of the drug's target protein within the virus-infected cell.
3. Activation of alternative pathways that allow the virus to replicate despite the presence of the drug.
4. Increased efflux of the drug from the virus-infected cell, reducing its intracellular concentration and effectiveness.

Viral drug resistance is a significant concern in the treatment of viral infections such as HIV, hepatitis B and C, herpes simplex virus, and influenza. It can lead to reduced treatment efficacy, increased risk of treatment failure, and the need for more toxic or expensive drugs. Therefore, it is essential to monitor viral drug resistance during treatment and adjust therapy accordingly to ensure optimal outcomes.

Polymerase Chain Reaction (PCR) is a laboratory technique used to amplify specific regions of DNA. It enables the production of thousands to millions of copies of a particular DNA sequence in a rapid and efficient manner, making it an essential tool in various fields such as molecular biology, medical diagnostics, forensic science, and research.

The PCR process involves repeated cycles of heating and cooling to separate the DNA strands, allow primers (short sequences of single-stranded DNA) to attach to the target regions, and extend these primers using an enzyme called Taq polymerase, resulting in the exponential amplification of the desired DNA segment.

In a medical context, PCR is often used for detecting and quantifying specific pathogens (viruses, bacteria, fungi, or parasites) in clinical samples, identifying genetic mutations or polymorphisms associated with diseases, monitoring disease progression, and evaluating treatment effectiveness.

Penicillin resistance is the ability of certain bacteria to withstand the antibacterial effects of penicillin, a type of antibiotic. This occurs when these bacteria have developed mechanisms that prevent penicillin from binding to and inhibiting the function of their cell wall biosynthesis proteins, particularly the enzyme transpeptidase.

One common mechanism of penicillin resistance is the production of beta-lactamases, enzymes that can hydrolyze and inactivate the beta-lactam ring structure present in penicillin and other related antibiotics. Another mechanism involves alterations in the bacterial cell wall that prevent penicillin from binding to its target proteins.

Penicillin resistance is a significant concern in clinical settings, as it can limit treatment options for bacterial infections and may necessitate the use of more potent or toxic antibiotics. It is important to note that misuse or overuse of antibiotics can contribute to the development and spread of antibiotic-resistant bacteria, including those resistant to penicillin.

Ampicillin is a penicillin-type antibiotic used to treat a wide range of bacterial infections. It works by interfering with the ability of bacteria to form cell walls, which are essential for their survival. This causes the bacterial cells to become unstable and eventually die.

The medical definition of Ampicillin is:

"A semi-synthetic penicillin antibiotic, derived from the Penicillium mold. It is used to treat a variety of infections caused by susceptible gram-positive and gram-negative bacteria. Ampicillin is effective against both aerobic and anaerobic organisms. It is commonly used to treat respiratory tract infections, urinary tract infections, meningitis, and endocarditis."

It's important to note that Ampicillin is not effective against infections caused by methicillin-resistant Staphylococcus aureus (MRSA) or other bacteria that have developed resistance to penicillins. Additionally, overuse of antibiotics like Ampicillin can lead to the development of antibiotic resistance, which is a significant public health concern.

Promoter regions in genetics refer to specific DNA sequences located near the transcription start site of a gene. They serve as binding sites for RNA polymerase and various transcription factors that regulate the initiation of gene transcription. These regulatory elements help control the rate of transcription and, therefore, the level of gene expression. Promoter regions can be composed of different types of sequences, such as the TATA box and CAAT box, and their organization and composition can vary between different genes and species.

Tetracycline resistance is a type of antibiotic resistance where bacteria have developed the ability to survive and grow in the presence of tetracyclines, a class of antibiotics used to treat a wide range of bacterial infections. This resistance can be mediated through various mechanisms such as:

1. Efflux pumps: These are proteins that actively pump tetracyclines out of the bacterial cell, reducing the intracellular concentration of the antibiotic and preventing it from reaching its target site.
2. Ribosomal protection proteins (RPPs): These proteins bind to the ribosomes (the sites of protein synthesis) and prevent tetracyclines from binding, thus allowing protein synthesis to continue in the presence of the antibiotic.
3. Enzymatic modification: Some bacteria produce enzymes that modify tetracyclines, rendering them ineffective or less effective against bacterial growth.
4. Mutations in target sites: Bacteria can also acquire mutations in their genome that alter the structure of the target site (ribosomes), preventing tetracyclines from binding and inhibiting protein synthesis.

Tetracycline resistance has become a significant public health concern, as it limits the therapeutic options for treating bacterial infections and contributes to the emergence and spread of multidrug-resistant bacteria. The primary causes of tetracycline resistance include the misuse and overuse of antibiotics in both human medicine and agriculture.

Genetic transcription is the process by which the information in a strand of DNA is used to create a complementary RNA molecule. This process is the first step in gene expression, where the genetic code in DNA is converted into a form that can be used to produce proteins or functional RNAs.

During transcription, an enzyme called RNA polymerase binds to the DNA template strand and reads the sequence of nucleotide bases. As it moves along the template, it adds complementary RNA nucleotides to the growing RNA chain, creating a single-stranded RNA molecule that is complementary to the DNA template strand. Once transcription is complete, the RNA molecule may undergo further processing before it can be translated into protein or perform its functional role in the cell.

Transcription can be either "constitutive" or "regulated." Constitutive transcription occurs at a relatively constant rate and produces essential proteins that are required for basic cellular functions. Regulated transcription, on the other hand, is subject to control by various intracellular and extracellular signals, allowing cells to respond to changing environmental conditions or developmental cues.

... show spontaneous emergence of chloramphenicol resistance. Three mechanisms of resistance to chloramphenicol are known: reduced ... Resistance-conferring mutations of the 50S ribosomal subunit are rare.[medical citation needed] Chloramphenicol resistance may ... Oily chloramphenicol (or chloramphenicol oil suspension) is a long-acting preparation of chloramphenicol first introduced by ... and this is the most common mechanism of low-level chloramphenicol resistance. High-level resistance is conferred by the cat- ...
... conferring resistance to chloramphenicol, which ensured only the successful recombinants grew. Triplicate plates of 10μL of ... and the cmr gene for chloramphenicol resistance. It was observed that leaky expression of Cas9 occurred even without induction ... After selecting for the transformants using antibiotic resistance, another plasmid containing the targeted gene of interest in ... such as antibiotic resistance, is transformed into the cells in place of the target gene and incorporated into the DNA behind a ...
Leclerq R (February 2002). "Mechanisms of Resistance to Macrolides and Lincosamides: Nature of the Resistance Elements and ... Its similarity to the mechanism of action of macrolides and chloramphenicol means they should not be given simultaneously, as ... During a D-test, bacteria of the iMLSB phenotype demonstrate in vitro erythromycin-induced in vitro resistance to clindamycin. ... Woods CR (December 2009). "Macrolide-inducible resistance to clindamycin and the D-test". The Pediatric Infectious Disease ...
Plasmids that carry several different resistance genes can confer resistance to multiple antibacterials. Cross-resistance to ... For example, chloramphenicol and tetracyclines are antagonists to penicillins. However, this can vary depending on the species ... The survival of bacteria often results from an inheritable resistance, but the growth of resistance to antibacterials also ... Several molecular mechanisms of antibacterial resistance exist. Intrinsic antibacterial resistance may be part of the genetic ...
Freeman, R. F.; Bibb, M. J.; Hopwood, D. A. (1977). "Chloramphenicol acetylransferase-independent chloramphenicol resistance in ...
Freeman, R. F.; Bibb, M. J.; Hopwood, D. A. (1977). "Chloramphenicol acetylransferase-independent chloramphenicol resistance in ...
Translational block to expression of the E. coli Tn9-derived chloramphenicol-resistance gene in Bacillus subtilis Proc. Natl. ... Expression of Tn9-derived chloramphenicol resistance in Bacillus subtilis. Nature 293:309-311. Goldfarb, D.S., R.L. Rodriguez ... RNA polymerase binding studies on antibiotic-resistance promoters. Gene. 9:175-193. Goldfarb, D.S., R.H. Doi and R. L. ...
"Anti-peptidyl transferase leader peptides of attenuation-regulated chloramphenicol-resistance genes". Proceedings of the ... The following protein synthesis inhibitors target peptidyl transferase: Chloramphenicol binds to A2451 and A2452 residues in ...
1975). "Cytoplasmic transfer of chloramphenicol resistance in human tissue culture cells". J Cell Biol. 67 (1): 174-88. doi: ... resistance to chloramphenicol) and in 1990 he described a mitochondrial DNA mutation as the cause of a particular form of ...
Other frequent resistance targets include aminoglycosides, fluoroquinolones, tetracyclines, chloramphenicol, and trimethoprim/ ... Resistance to phages is not likely to be as troublesome as to antibiotics as new infectious phages are likely to be available ... The most important mechanism of resistance by CRKP is the production of a carbapenemase enzyme, blakpc. The gene that encodes ... In 2009, strains of K. pneumoniae with gene called New Delhi metallo-beta-lactamase ( NDM-1) that even gives resistance against ...
The plasmid also carries genes to confer resistance to ampicillin and chloramphenicol. Plasmid pHT01 is generally stable in ...
Kapoor, Garima; Saigal, Saurabh; Elongavan, Ashok (2017). "Action and resistance mechanisms of antibiotics: A guide for ... Chloramphenicol, Tetracyclines, Macrolides, Clindamycin, Streptogramins, & Linezolid , Katzung & Trevor's Pharmacology: ... and Epidemiology of Bacterial Resistance". Microbiology and Molecular Biology Reviews. 65 (2): 232-260. doi:10.1128/MMBR.65.2. ...
... that detoxifies the antibiotic chloramphenicol and is responsible for chloramphenicol resistance in bacteria. This enzyme ... Chloramphenicol binds in a deep pocket located at the boundary between adjacent subunits of the trimer, such that the majority ... The crystal structure of the type III enzyme from Escherichia coli with chloramphenicol bound has been determined. CAT is a ... Shaw WV, Packman LC, Burleigh BD, Dell A, Morris HR, Hartley BS (1979). "Primary structure of a chloramphenicol ...
It has shown resistance to gentamicin. Treatment is recommended for a minimum of three weeks. Hospitalization is required in ... C. canimorsus is susceptible to ampicillin, third-generation cephalosporins, tetracyclines, clindamycin, and chloramphenicol. ... C. canimorsus cells also show resistance to killing by complement and killing by polymorphonuclear leukocytes (PNMs). C. ... although some isolates have been found to show resistance. ...
Doxycycline is typically used first line, although some strains of V. cholerae have shown resistance. Testing for resistance ... Other antibiotics proven to be effective include cotrimoxazole, erythromycin, tetracycline, chloramphenicol, and furazolidone. ... In many areas of the world, antibiotic resistance is increasing within cholera bacteria. In Bangladesh, for example, most cases ... In those samples that test positive, further testing should be done to determine antibiotic resistance. In epidemic situations ...
... but chloramphenicol is an alternative. Strains that are resistant to doxycycline and chloramphenicol have been reported in ... Azithromycin is an alternative in children and pregnant women with scrub typhus, and when doxycycline resistance is suspected. ... yet it can be treated effectively with chloramphenicol. Where doubt exists, the diagnosis may be confirmed by a laboratory test ...
Drug resistance, such as antimicrobial resistance or antineoplastic resistance, may make the first-line drug ineffective, ... Unacceptably high risk of irreversible, fatal aplastic anemia and gray baby syndrome causes intravenous chloramphenicol to be a ... or vancomycin intermediate-resistance S. aureus (VISA)) often coinciding with methicillin/penicillin resistance, prompting the ... Recently, resistance to even vancomycin has been shown in some strains of S. aureus (sometimes referred to as vancomycin ...
Resistance to rifampicin has been noted to increase after use, which has caused some to recommend considering other agents. ... Chloramphenicol, either alone or in combination with ampicillin, however, appears to work equally well. Empirical therapy may ... In the US, where resistance to cefalosporins is increasingly found in streptococci, addition of vancomycin to the initial ...
Most strains of C. pseudotuberculosis have been shown to be intrinsically resistant to streptomycin, with varying resistance to ... It has been shown to be susceptible to ampicillin, gentamicin, tetracycline, lincomycin, and chloramphenicol. Vaccines have ... Specifically, C. pseudotuberculosis is intrinsically resistant to streptomycin, with varying resistance to penicillin and ... chloramphenicol, and others. Treatment within live animals (in vivo) is thought to be limited due to the firm capsule and thick ...
... chloramphenicol and florfenicol. This multi-drug resistance has been linked to certain genes. For beta-lactam resistance, the ... lincomycin and chloramphenicol. Further resistance testing of S. hyicus isolates found high resistance to penicillin, ... lincosamides and streptogramins and the pS194-like str gene is for chloramphenicol and streptomycin resistance. Genetic ... With antibiotic resistance increasing in all bacteria, sending samples to a diagnostic lab for susceptibility testing is ...
Mdt is effective at providing the bacteria with resistance to tetracycline, chloramphenicol, lincosamides and streptomycin. The ... Cd2+ and Zn2+ resistance) in Pseudomonas aeruginosa, and Czn (Cd2+, Zn2+, and Ni2+ resistance) in Helicobacter pylori. It has ... "Overexpression of resistance-nodulation-cell division pump AdeFGH confers multidrug resistance in Acinetobacter baumannii". ... Heavy metal resistance by the RND family was first discovered in R. metallidurans through the CzcA and later the CnrA protein. ...
Mechanisms of antibiotic resistance can be categorized into three groups. First, resistance can be achieved by reducing ... The second, AdeDE, is responsible for efflux of a wide range of substrates, including tetracycline, chloramphenicol, and ... AbaR's contain several genes for antibiotic resistance, all flanked by insertion sequences. There exist several resistance ... strain showing resistance to 12 antibiotics. AbsR25 sRNA could play a role in the efflux pump regulation and drug resistance. A ...
The adapted strain acquired resistance to not only chloramphenicol, but also cross-resistance to other antibiotics; this was in ... Antibiotic resistance is a subset of antimicrobial resistance. This more specific resistance is linked to bacteria and thus ... Resistance in bacteria can arise naturally by genetic mutation, or by one species acquiring resistance from another. Resistance ... Fungi evolve antifungal resistance. Viruses evolve antiviral resistance. Protozoa evolve antiprotozoal resistance, and bacteria ...
"Two distinct major facilitator superfamily drug efflux pumps mediate chloramphenicol resistance in Streptomyces coelicolor". ... and acquired resistance respectively. As an intrinsic mechanism of resistance, efflux pump genes can survive a hostile ... The small multidrug resistance family (SMR) The resistance-nodulation-cell division superfamily (RND) The multi antimicrobial ... "AcrAB efflux pump plays a major role in the antibiotic resistance phenotype of Escherichia coli multiple-antibiotic-resistance ...
Resistance to chloramphenicol became frequent in Southeast Asia by the 1950s, and today chloramphenicol is only used as a last ... As resistance to ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole, and streptomycin is now common, these agents are ... Resistance to these antibiotics has been developing, which has made treatment more difficult. In 2015, 12.5 million new typhoid ... Where resistance is uncommon, the treatment of choice is a fluoroquinolone such as ciprofloxacin. Otherwise, a third-generation ...
Benzylpenicillin and chloramphenicol are also effective. Supportive measures include IV fluids, oxygen, inotropic support, e.g ... Antibiotic choice should be based on local antibiotic resistance information. Complications following meningococcal disease can ... and chloramphenicol (12 deaths out of 256). There were no reported side effects. Both antibiotics were considered equally ... although rifampin was associated with resistance to the antibiotic following treatment. Eighteen studies provided data on side ...
In Southeast Asia, where doxycycline and chloramphenicol resistance have been experienced, azithromycin is recommended for all ... Smadel, JE; Ley, H.L.Jr.; Diercks, F.H.; Traub, R. (1950). "Immunity in scrub typhus: resistance to induced reinfection". A.M.A ... Antibiotics such as azithromycin and doxycycline are the main prescription drugs; chloramphenicol and tetracyclin are also ... Chanta, C.; Phloenchaiwanit, P. (2015). "Randomized Controlled trial of azithromycin versus doxycycline or chloramphenicol for ...
... flexneri have more plasmids that are suspected to confer antibiotic resistance. Some strains of S. flexneri have resistance to ... It has been found that chloramphenicol, nalidixic acid, and gentamicin are still effective antibiotics for some strains. ... Ssr1 sRNA, which could play role in resistance to acidic stress and regulation of virulence was shown to exist only in Shigella ... "Molecular characteristics of class 1 and class 2 integrons and their relationships to antibiotic resistance in clinical ...
Early clinical experience suggested that chloramphenicol may also be effective, but in vitro susceptibility testing revealed ... resistance.[citation needed] Ehrlichiosis is a nationally notifiable disease in the United States. Cases have been reported in ...
... and chloramphenicol. There have been several reports of antibiotic resistance in V. parvula isolates in different countries. In ... Teng LJ, Hsueh PR, Tsai JC, Liaw SJ, Ho SW, Luh KT (September 2002). "High incidence of cefoxitin and clindamycin resistance ... June 2008). "Effect of Veillonella parvula on the antimicrobial resistance and gene expression of Streptococcus mutans grown in ... Maraki S, Mavromanolaki VE, Stafylaki D, Kasimati A (April 2020). "Surveillance of antimicrobial resistance in recent clinical ...
Defective ribosome assembly causes aminoglycoside resistance and collateral sensitivity to chloramphenicol in Pseudomonas ...
... resistance has been demonstrated by removing the nuclei of cells of the CAP-resistant HeLa strain 296 ... Cytoplasmic transfer of chloramphenicol resistance in human tissue culture cells. D C Wallace, D C Wallace ... D C Wallace, C L Bunn, J M Eisenstadt; Cytoplasmic transfer of chloramphenicol resistance in human tissue culture cells.. J ... The cytoplasmic inheritance of human chloramphenicol (cap) resistance has been demonstrated by removing the nuclei of cells of ...
The level of intrinsic resistance to both chloramphenicol and tetracycline was increased about twofold. Also, the levels of R ... to the drugs and that this acts syner-gistically with the products of the R factor chloramphenicol and tetracycline resistance ... factor-determined resistance to these drugs were increased by this host mutation and tetracycline resistance was expressed ... the level of resistance of a partially tetracycline-sensitive mutant of r100-1 is described. Plasmid-less derivatives of these ...
... show spontaneous emergence of chloramphenicol resistance. Three mechanisms of resistance to chloramphenicol are known: reduced ... Resistance-conferring mutations of the 50S ribosomal subunit are rare.[medical citation needed] Chloramphenicol resistance may ... Oily chloramphenicol (or chloramphenicol oil suspension) is a long-acting preparation of chloramphenicol first introduced by ... and this is the most common mechanism of low-level chloramphenicol resistance. High-level resistance is conferred by the cat- ...
Chloramphenicol. NA. ,256. R. Amoxicillin-clavulanic acid. 14. 16. I. Ertapenem. NA. ≤0.5. S. ... Shigella flexneri with Ciprofloxacin Resistance and Reduced Azithromycin Susceptibility, Canada, 2015 Christiane Gaudreau. , ... Shigella flexneri with Ciprofloxacin Resistance and Reduced Azithromycin Susceptibility, Canada, 2015. ... and the susceptibility and resistance breakpoints for the other 11 antimicrobial agents were CLSI Enterobacteriaceae ...
This family consists of chloramphenicol (Cm) resistance gene leader peptides ... Chloramphenicol resistance gene leader peptide. This family consists of chloramphenicol (Cm) resistance gene leader peptides. ... Inducible resistance to Cm in both Gram positive and Gram negative bacteria is controlled by translation attenuation. In ... allowing initiation of translation of the Cm resistance gene. ... for the resistance determinant is sequestered in a secondary ...
Resistance to chloramphenicol is mediated through bacterial elaboration of chloramphenicol acetyltransferase, which is found in ... The high rates of morbidity and mortality have been ascribed in part to the high rates of resistance to chloramphenicol and the ... Previously, ampicillin and chloramphenicol were recommended for the treatment of Hib meningitis. However, resistance to both ... In addition to the growing problem of resistance, chloramphenicol has other disadvantages. Toxic effects (eg, bone marrow ...
Discover the impact of the mucoid phenotype on antibiotic resistance in Klebsiella pneumoniae. Explore the prevalence, ... and chloramphenicol (62.5%). A high antibiotic resistance rate could be detected more often in mucoid (hv) strains than non- ... Therefore, resistance to a member of a class could confer resistance to other members of the same class. Cross resistance is ... The mechanism of ESBL resistance has been implicated in the virulence of the organism by decreasing/increasing resistance to ...
... antimicrobial resistance genes, and plasmid types by using the in-house Galaxy platform. The antimicrobial resistance of ... antimicrobial resistance genes, and plasmid types by using the in-house Galaxy platform. The antimicrobial resistance of ... All the isolates were multidrug-resistant and the highest resistance was observed against antimicrobials tetracycline (95.4%) ... All the isolates were multidrug-resistant and the highest resistance was observed against antimicrobials tetracycline (95.4%) ...
Worldwide, however, meningococcal strains have shown increasing resistance to chloramphenicol, and patients with pneumococcal ... No cross-resistance has been demonstrated. Mycobacterial resistance is frequent with previous therapy. ... Chloramphenicol is effective against gram-negative and gram-positive bacteria. It can be used as a substitute in the treatment ... Chloramphenicol inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit. ...
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Categories: Chloramphenicol Resistance Image Types: Photo, Illustrations, Video, Color, Black&White, PublicDomain, ...
Drug-resistance declines in the laboratory in an antibiotic stress-free environment, indicating that restricting antimicrobial ... Chloramphenicol. CHL. Chloramphenicol. Protein synthesis, 50S. Bacteriostatic. 2. Erythromycin. ERY. Macrolides. Protein ... Fitness recovery and resistance loss after compensatory evolution.. (A) The scatterplot shows the relative resistance level and ... 2010) Antibiotic resistance and its cost: is it possible to reverse resistance? Nature Reviews Microbiology 8:260-271. ...
Bacterial Resistance(s). Chloramphenicol, 25 μg/mL * Growth Temperature. 37°C * Growth Strain(s) ...
WGS of bacteria from 10 peoples samples predicted resistance to chloramphenicol, streptomycin, sulfisoxazole, tetracycline, ... of three peoples samples using standard antibiotic susceptibility testing methods by CDCs National Antimicrobial Resistance ...
Interestingly, 48 of 90 (53%) of swine E. coli isolates exhibited resistance to chloramphenicol (CML), an antibiotic that has ... Title: CHARACTERIZATION OF CHLORAMPHENICOL RESISTANCE IN BETA-HEMOLYTIC ESCHERICHIA COLI ASSOCIATED WITH DIARRHEA IN NEONATAL ... resistance to it still remains. This work also shows that resistance of pathogenic E. coli strains to a number of other ... CML resistance was observed in all of the major ribogroups with the exception of one. The identification of the cmlA gene among ...
Explore their antibiotic resistance and heavy metal tolerance, while uncovering their potential for industrial enzyme ... The harmful effects of these isolates were evidenced by antibiotic resistance, heavy metal tolerance and antibacterial activity ... They were resistant to the antibiotics like amoxiclav, methicillin, chloramphenicol and streptomycin. They showed tolerance to ...
Resistance. The major route of resistance is modification of the 23S rRNA in the 50S ribosomal subunit to insensitivity while ... Antagonism exists in vitro between erythromycin and clindamycin, lincomycin, and chloramphenicol. Antimicrobial Activity. ... increase the likelihood that bacteria will develop resistance and will not be treatable by ERY-TAB ® or other antibacterial ...
The low resistance towards chloramphenicol might be because its use is rare at local dairy farms. The isolated bacteria ... Antibiotic resistance pattern. Variable trends of antibiotic resistance were shown by both types of (Gram-negative and Gram- ... less resistance of Escherichia was also observed to cefixime (23%), chloramphenicol, gentamycin, and tetracycline (15% each), ... These bacteria interact with antibiotics which can be present in the food system and develop resistance. Antibiotic resistance ...
... sector join forces with the NHS to pilot an antibiotic amnesty in response to the ever-growing concern of antibiotic resistance ... Resistance was less commonly reported for chloramphenicol, sulfonamides, and quinolones.. The authors stress that the ... The study agreed to a large extent with other literature investigating the emergence of antimicrobial resistance in reptiles. ... The bacteria exhibited diverse degrees of resistance against most of the antimicrobials, including cephalosporins (cefalexin, ...
Recommendations for preventing the spread of vancomycin resistance: recommendations of the Hospital Infection Control Practices ... chloramphenicol, trimethoprim-sulfamethoxazole, and tetracycline. The patient is continuing to receive antimicrobial therapy. ... by which these strains develop resistance. Reported by: R Martin, DrPH, KR Wilcox, MD, State Epidemiologist, Michigan Dept of ... aureus strains with full resistance to vancomycin will emerge. In July 1997, VISA-associated peritonitis was diagnosed in a ...
Emergence of resistance to chloramphenicol among vancomycin-resistant enterococcal (VRE) bloodstream isolates. Int J Antimicrob ... Chloramphenicol: A variety of single agents may be effective for the treatment of UTIs caused by VRE. Chloramphenicol, a broad- ... VanA is responsible for a high level of resistance to vancomycin, whereas VanB confers a lower level of resistance. Most VRE ... Resistant Enterococcus: Enterococci impart resistance to antibiotics in a variety of ways. Although some species are inherently ...
The trends of antibiotic resistance and the toxinogenic ,i,S. aureus,/i, carried by the poultry intended for consumption in ... Preventive and containment measures should be implemented in order to limit the dissemination of resistance genes through the ... showed resistance to ciprofloxacin. The ,i,mec,/i,A and ,i,mec,/i,C were not identified in any of the recovered isolates. Of ... The transmission of antibiotic resistance to human population through food consumption is a global public health threat. This ...
She grew 3 different types of ccdB, all identical except for resistance. One was kanamycin, one was chloramphenicol, and one ... so that she could later cut out the resistance, in case the first method of changing resistance didnt work. These colonies ... The cytoslac DNAs resistance would have to be removed in order for the system to work. To do this, Faige digested cytoslac DNA ... For one because we were making the plates with a certain resistance in the hope that we could test it with the biobricks in the ...
Extensive Characterisation of new B.subtilis biobricks, Chloramphenicol resistance gene and motility ... AB is our antibiotic resistance cassette, ytvA is the gene controlling the light-sensing pathway, SB is the biomaterial, epsE ... Characterized and improved the existing part BBa J31005 (chloramphenicol acetyl transferase, CAT) ...
Staphylococcus aureus was most susceptible to ciprofloxacin and showed greatest resistance to chloramphenicol. Coliform ... It is most susceptible to ciprofloxacin and resistant to chloramphenicol. There is benefit in conducting a larger study with ... organisms were most susceptible amikacin and showed greatest resistance to augmentin.. Conclusions: The predominant bacterium ...
  • Chloramphenicol is an antibiotic useful for the treatment of a number of bacterial infections. (
  • Chloramphenicol is a broad-spectrum antibiotic that typically stops bacterial growth by stopping the production of proteins. (
  • In the context of preventing endophthalmitis, a complication of cataract surgery, a 2017 systematic review found moderate evidence that using chloramphenicol eye drops in addition to an antibiotic injection (cefuroxime or penicillin) will likely lower the risk of endophthalmitis, compared to eye drops or antibiotic injections alone. (
  • The non-mucoid strains showed no complete resistant to any antibiotic tested but had a higher resistant rate to chloramphenicol only. (
  • The Multiple Antibiotic Resistance (MAR) index shows the themucoid strains with a high MAR index range of 0.7 - 1.0 with a median MAR index of 0.8, while the non-mucoid strains had a MAR index of 0.2 - 0.8 with a median MAR index of 0.35. (
  • Umar, U. , Anagor, S. , Aliyu, A. and Suleiman, A. (2016) Hypermucoviscosity in Clinical Isolates of Klebsiella pneumoniae Correlates with High Multiple Antibiotic Resistance (MAR) Index. (
  • Antibiotic resistance typically induces a fitness cost that shapes the fate of antibiotic-resistant bacterial populations. (
  • We have demonstrated that drug-resistance frequently declines within 480 generations during exposure to an antibiotic-free environment. (
  • The extent of resistance loss was found to be generally antibiotic-specific, driven by mutations that reduce both resistance level and fitness costs of antibiotic-resistance mutations. (
  • We conclude that phenotypic reversion to the antibiotic-sensitive state can be mediated by the acquisition of additional mutations, while maintaining the original resistance mutations. (
  • Such strategies implicitly presume that resistance leads to reduced bacterial fitness in an antibiotic-free environment, and therefore these resistant populations should be rapidly outcompeted by antibiotic-sensitive variants. (
  • In theory, the extent of fitness costs determines the long-term stability of resistance, and consequently, the rate by which the frequency of resistant bacteria decreases in an antibiotic-free environment. (
  • However, in other cases, such deleterious side effects of resistance mutations are undetectable, and resistance can even confer benefits in specific, antibiotic-free environmental settings ( Maharjan and Ferenci, 2017 ). (
  • ABSTRACT An analytical cross-sectional study determined the serogroups and serotypes of Vibrio cholerae , and their antibiotic resistance rates, in the 2005 cholera epidemic in Hamadan. (
  • Testing of three people's samples using standard antibiotic susceptibility testing methods by CDC's National Antimicrobial Resistance Monitoring System (NARMS) confirmed these results (streptomycin was not tested by this method). (
  • We characterized the antibiotic resistance profiles of 90 pathogenic E. coli isolated from baby pigs. (
  • Interestingly, 53% of the isolates were resistant to chloramphenicol (CML), an antibiotic that has not been approved for use in food animals in the U.S. since the mid 1980s. (
  • The harmful effects of these isolates were evidenced by antibiotic resistance, heavy metal tolerance and antibacterial activity. (
  • November saw the veterinary sector join forces with the NHS to pilot an antibiotic amnesty in response to the ever-growing concern of antibiotic resistance in humans and domestic animals. (
  • This quarter's Featured Article reminds us that not only cats and dogs require prudent use of antibiotics, as the authors studying antibiotic resistance in 398 pet reptiles found. (
  • The Romanian study focused on the analysis of pathologies responsible for diseases in pets kept in terrariums, aiming to better understand the features of antibiotic therapy, bacterial load and antibiotic resistance in the species. (
  • Long-term antimicrobial treatments have undoubtedly influenced the evolution of resistant strains, with the majority of bacteria in this study exhibiting resistance against the majority of commonly used antibiotic combinations, including penicillins, cephalosporins, macrolides and tetracyclines. (
  • Published in Animals (, this study further highlights the importance of careful antibiotic therapy in all pet species, domestic and exotic, to counteract the evolution of resistance. (
  • Once Enterococcus species colonize the GI tract, the development of antibiotic resistance increases, as does the risk of transmission between patients and providers. (
  • The transmission of antibiotic resistance to human population through food consumption is a global public health threat. (
  • The trends of antibiotic resistance and the toxinogenic S. aureus carried by the poultry intended for consumption in Tangier present a huge concern. (
  • A British study on antimicrobial resistance (AMR) estimated that 700,000 persons are dying each year worldwide due to antibiotic-resistant infections [ 4 ]. (
  • AB is our antibiotic resistance cassette, ytvA is the gene controlling the light-sensing pathway, SB is the biomaterial, epsE the clutch and the 5' and 3' sections are integration sites. (
  • The aims of this research work were to determine the patterns of antibiotic resistance in Escherichia coli isolates from the meat of wild or domestically reared pigeons from Spain, to detect the presence of virulence and antibiotic resistance genes, and to carry out a phylogenetic classification of the isolates. (
  • Chloramphenicol is a broad-spectrum antibiotic, inhibiting gram-positive and gram-negative organisms, aerobic and anaerobic bacteria, and many intracellular organisms. (
  • The second method uses chloramphenicol, an antibiotic that halts protein synthesis and decouples it from plasmid replication, when culturing strains containing a plasmid with a relaxed origin of replication. (
  • Evolving bacteria in the laboratory reveals how a protein that causes antibiotic resistance may change and lead to the creation of superbugs. (
  • Antibiotic resistance is a major threat to global health, and understanding how it emerges and spreads is an important area of research. (
  • Identifying which mutations enhance its activity and protect bacteria is vital for designing strategies that fight antibiotic resistance. (
  • Why is Chloramphenicol a Broad Spectrum Antibiotic? (
  • Let's embark on a journey to uncover why Chloramphenicol is hailed as a versatile antibiotic. (
  • Chloramphenicol exerts its antibiotic prowess by inhibiting bacterial protein synthesis. (
  • Chloramphenicol Test Fluorescence journey from the soil to the laboratory has paved the way for a broad-spectrum antibiotic that has saved countless lives. (
  • The intestinal microbiota is considered to be a major reservoir of antibiotic resistance determinants (ARDs) that could potentially be transferred to bacterial pathogens via mobile genetic elements. (
  • The intestinal microbiota plays a pivotal role in this phenomenon as it harbours a vast diversity of bacterial species, some of them possessing antibiotic resistance determinants (ARDs) that may enable their survival under antibiotic exposure. (
  • One example is the ACCoT plasmid (A=ampicillin, C=chloramphenicol, Co=co-trimoxazole, T=tetracycline), which mediates multiple drug resistance in typhoid (also called R factors). (
  • In combination with sulfadiazine, chloramphenicol remained the treatment of choice until this role was assumed by ampicillin. (
  • These agents are at least as effective as the older regimen of combination therapy with ampicillin and chloramphenicol and are more effective in children who are infected with microbes that are resistant to ampicillin or chloramphenicol. (
  • One was kanamycin, one was chloramphenicol, and one was ampicillin resistant. (
  • Antimicrobial resistance has emerged in Salmonella enterica, initially to the traditional first-line drugs chloramphenicol, ampicillin, and trimethoprim-sulfamethoxazole. (
  • Agreement between ceftiofur resistance and coresistance to ampicillin, chloramphenicol, streptomycin, sulfisoxazole, and tetracycline was almost perfect (κ 0.97). (
  • Mutation of the bacteria to high ampicillin resistance occurred at a frequency of 10 −3 to 10 −4 and it was coupled with a simultaneous increase in resistance to chloramphenicol, streptomycin and sulphanilamide. (
  • Increased ampicillin resistance was due to increased penicillinase activity of the bacteria. (
  • V. cholerae isolated at a national referral laboratory from 1999 to 2012 were retrospectively analysed and evaluated for resistance to ampicillin, tetracycline, chloramphenicol, co-trimoxazole and ofloxacin. (
  • Antimicrobial susceptibility data revealed increasing resistance to co-trimoxazole and ampicillin, but strains remained highly susceptible to ofloxacin. (
  • 13.0% (18/138) with the most common resistance profile being resistance to ampicillin-chloramphenicol-ciprofloxacin from Salmonella Enteritidis isolates ( n = 5). (
  • Variations in resistance to three antibiotics among some single-step mutants to chloramphenicol resistance in a strain of Escherichia coli K12. (
  • The data suggest that the mucoid phenotype could be associated with extrachromsomal element(s) carrying resistance genes to antibiotics and that these extrachromosomal elements may not harbour resistance determinants to chloramphenicol. (
  • This work also shows that resistance of pathogenic E. coli strains to a number of other antibiotics may become a problem for swine producers in the future unless these antibiotics are used appropriately and judiciously. (
  • They were resistant to the antibiotics like amoxiclav, methicillin, chloramphenicol and streptomycin. (
  • Enterococci impart resistance to antibiotics in a variety of ways. (
  • Monitoring resistance to antibiotics in wild animals may assist in evaluating tendencies in the evolution of this major public health problem. (
  • Within the United States, poverty-driven practices such as medication-sharing, use of "leftover" antibiotics, and the purchase and use of foreign-made drugs of questionable quality are likely contributing to antimicrobial resistance. (
  • Resistance to all the antibiotics was infective. (
  • causing gastroenteritis has developed resistance to commonly used antibiotics. (
  • To date, Cfr has been found to cause resistance to eight different classes of antibiotics. (
  • They could also help researchers design a new generation of antibiotics that can overcome resistance caused by the Cfr protein. (
  • Clostridium perfringens strains were isolated, identified, and examined by disc susceptibility tests for their resistance to several antibiotics. (
  • 1. Bacterial resistance to beta-lactam antibiotics has risen dramatically in Escherichia coli from food animals. (
  • In the realm of antibiotics, Chloramphenicol stands out as a potent and broad-spectrum option. (
  • As with many antibiotics, bacterial resistance to Chloramphenicol has emerged over time. (
  • Resistance to first-line antibiotics limits the therapeutic choices for Salmonella infection. (
  • Resistance to furazolidone, trimethoprim-sulfamethoxazole and erythromycin was 100%, 98% and 62% respectively. (
  • Some strains of E. coli, for example, show spontaneous emergence of chloramphenicol resistance. (
  • medical citation needed] As of 2014 some Enterococcus faecium and Pseudomonas aeruginosa strains are resistant to chloramphenicol. (
  • and Staphylococcus capitis strains have also developed resistance to chloramphenicol to varying degrees. (
  • Furthermore, the extrachromosomal elements bearing the mucoid phenotype and the resistance elements in the mucoid strains do not significantly impact on the fitness of the cognate strain. (
  • Our study demonstrated the prevalence of antimicrobial resistance in Salmonella strains isolated from pig slaughterhouses in China and suggested that the genomic platform can serve as routine surveillance along with the food-chain investigation. (
  • We present our study on the efficacy and phenotypic impact of compensatory evolution in Escherichia coli strains carrying multiple resistance mutations. (
  • The identification of the cmlA gene among diverse hemolytic ETEC strains suggests broad dissemination of this genotype in the swine production environment, and that the CML resistance phenotype persists even in the absence of CML selection pressure. (
  • This report describes the first isolation of VISA from a patient in the United States, which may be an early warning that S. aureus strains with full resistance to vancomycin will emerge. (
  • Epidemiologic and laboratory investigations are under way to assess the risk for person-to-person transmission of VISA and to determine the mechanism(s) by which these strains develop resistance. (
  • This report documents the emergence of VISA in the United States and may signal the eventual emergence of S. aureus strains with full resistance to vancomycin. (
  • More than half of the strains (54%) were resistant to penicillin, 29.4% to tetracycline, 23.5% to erythromycin, and 17% showed resistance to ciprofloxacin. (
  • Resistance to extended-spectrum cephalosporins has occurred more often in nontyphoidal than in typhoidal Salmonella strains. (
  • Metabolism of chloramphenicol in strains containing R1 B1 was greater than in those with R 1a. (
  • Genetic analyses showed that 3 of the resistant strains carried conjugative R‐plasmids which carried the tetracycline resistance determinants. (
  • Chloramphenicol has a broad spectrum of activity and has been effective in treating ocular infections such as conjunctivitis, blepharitis etc. caused by a number of bacteria including Staphylococcus aureus, Streptococcus pneumoniae, and Escherichia coli. (
  • It is easy to select for reduced membrane permeability to chloramphenicol in vitro by serial passage of bacteria, and this is the most common mechanism of low-level chloramphenicol resistance. (
  • Inducible resistance to Cm in both Gram positive and Gram negative bacteria is controlled by translation attenuation. (
  • Whether these phenotype and resistances that had no fitness cost to the bacterium could significantly affect the virulence of the bacteria in vivo remains to be investigated. (
  • and Dr. Louise Francois Watkins, a Medical Officer, all with CDC's National Antimicrobial Resistance Monitoring System for Enteric Bacteria Team within the National Center for Emerging and Zoonotic Infectious Diseases. (
  • Zoonotic resistant bacteria and resistance genes could be transferred not only to people with occupational livestock exposure but also other persons in the community through direct contact with animals, via the food chain or by environment [ 9 , 10 ]. (
  • They have some features in common - for example they inhibit protein synthesis in bacteria (with macrolides, lincosamides, and chloramphenicol acting at a similar site), and have some similar pharmacokinetic features. (
  • These disadvantages still exist, but the activity of chloramphenicol against bacteria (e.g., staphylococci) that are resistant to other oral drugs has created increased use of chloramphenicol in recent years. (
  • Recent studies have discovered populations of resistant bacteria carrying a gene for a protein named chloramphenicol-florfenicol resistance, or Cfr for short. (
  • While many bacteria have intrinsic, chromosomally encoded ARDs and the capability of increasing resistance through mutation, they can also enrich their resistance capabilities through the acquisition of exogenous ARDs located on mobile genetic elements (MGEs) such as plasmids, transposons or phages. (
  • Staphylococcus aureus was most susceptible to ciprofloxacin and showed greatest resistance to chloramphenicol. (
  • When using CILOXAN eye drops one should take into account the risk of rhinopharyngeal passage which can contribute to the occurrence and the diffusion of bacterial resistance. (
  • Beyond human medicine, Chloramphenicol is employed in veterinary practices to treat bacterial infections in animals. (
  • What are some alternatives to Chloramphenicol in treating bacterial infections? (
  • There are several alternatives, including penicillin, cephalosporins, and tetracyclines, depending on the type of infection and bacterial resistance patterns. (
  • No, Chloramphenicol is only effective against bacterial infections and has no impact on viruses. (
  • The susceptibility pattern indicates that the bacterial isolates exhibited a varying level of resistance to two or more antimicrobial agents with maximum resistance to amoxicillin. (
  • A cmlB mutant accumulated tetracycline at a threefold] lower rate than the wild-type strain, and it is proposed that the mutants have an altered permeability to the drugs and that this acts syner-gistically with the products of the R factor chloramphenicol and tetracycline resistance genes. (
  • Characteristics of some single step mutants to chloramphenicol resistance in Escherichia coli K12 and their interactions with R-factor genes. (
  • Antimicrobial resistance occurs through different mechanisms, which include spontaneous (natural) genetic mutations and horizontal transfer of resistant genes through deoxyribonucleic acid (DNA). (
  • This report presents the status of AMR in Africa by analysing the main types of resistance and the underlying genes where possible. (
  • All the Salmonella isolates were subjected to whole genome sequencing, bioinformatics analysis for serovar predictions, multi-locus sequence types, antimicrobial resistance genes, and plasmid types by using the in-house Galaxy platform. (
  • Furthermore, significant advancements have been achieved in understanding and prediction of antimicrobial resistance of the Salmonella ( 11 , 14 , 18 , 19 ), and the knowledge of the antimicrobial resistance genes and plasmids are improving. (
  • Preventive and containment measures should be implemented in order to limit the dissemination of resistance genes through the food chain and to reduce their increased rate. (
  • Decreased fluoroquinolone susceptibility and then fluoroquinolone resistance have developed in association with chromosomal mutations in the quinolone resistance-determining region of genes encoding DNA gyrase and topoisomerase IV and also by plasmid-mediated resistance mechanisms. (
  • medical citation needed] Chloramphenicol resistance may be carried on a plasmid that also codes for resistance to other drugs. (
  • Plasmid-mediated gene complexes confer high-level resistance to vancomycin and are often used as targets for molecular detection of VRE. (
  • To do this, Faige digested cytoslac DNA in preparation for a 3-way ligation and then ran the digest on a gel, extracting the insert containing cytoslac and leaving behind the plasmid containing the resistance. (
  • The pLacI plasmid confers chloramphenicol resistance and provides enough lac repressor to inhibit transcription from the T7 lac promoter in the absence of inducer. (
  • Chloramphenicol treatment can stop protein production but allow the E. coli to continue to "amplify" the plasmids, resulting in increased yields during plasmid purification 1 . (
  • One method for plasmid amplification uses an inhibitory amount of chloramphenicol (170 µg/ml) added to a culture, which is then incubated further until plasmid purification (typically the next day) 2 . (
  • A variation of this method that reports higher plasmid yield uses lower amounts of chloramphenicol (10-20 µg/ml) added to exponentially growing cells that are subsequently incubated overnight prior to plasmid purification 3 . (
  • Alternatively, another study demonstrated increased plasmid yield by growth in the presence of sub-inhibitory concentrations of chloramphenicol (3-5 µg/ml) from the time of culture inoculation until plasmid was harvested the next day 4 . (
  • Chloramphenicol replaced streptomycin in 1950 because its excellent penetration of the blood-brain barrier eliminated the need for intrathecal treatment. (
  • Coliform organisms were most susceptible amikacin and showed greatest resistance to augmentin. (
  • It is most susceptible to ciprofloxacin and resistant to chloramphenicol. (
  • Comparison with the results of the 1998 epidemic suggests a worrying increase in the resistance of V. cholerae to erythromycin, doxycycline and ciprofloxacin. (
  • Isolates were found less resistant to gentamycin, chloramphenicol, and ciprofloxacin. (
  • 7 In tropical countries, there has been an emergence of Streptococcus pneumoniae that is resistant to penicillin, cefotaxime, and chloramphenicol. (
  • Because of the emergence of PNSP, in December 1994, the New York City Department of Health (NYCDOH) amended the New York City health code to require reporting of PNSP to monitor the local prevalence of resistance to penicillin. (
  • No differences in the levels of chloramphenicol or penicillin resistance were observed. (
  • Antagonism exists in vitro between erythromycin and clindamycin, lincomycin, and chloramphenicol. (
  • SUMMARY: The isolation of Escherichia coli chromosomal mutants that increased, the level of resistance of a partially tetracycline-sensitive mutant of r 100-1 is described. (
  • Inhibition of fertility by multiple drug-resistance factor (R) in Escherichia coli K-12. (
  • Resistance of Escherichia coli to tetracyclines. (
  • Changes in permeability to tetracyclines in Escherichia coli bearing transmissible resistance factors. (
  • Genetic analysis of some mutations causing resistance to tetracycline in Escherichia coli K12. (
  • As antimicrobial resistance continues to rise globally, multidrug-resistant (MDR) organisms have posed a significant challenge for clinicians, owing to the dearth of effective therapeutic options to combat them. (
  • 1-3 Multiple poverty-driven factors that contribute to the development of multidrug-resistant organisms have been identified, some of which may be directly affecting resistance in the United States. (
  • Reasons for multidrug-resistant organisms in developing countries are numerous, but the inadequate access to effective drugs, the unregulated manufacture and dispensation of antimicrobials, and the lack of money available to pay for appropriate, high-quality medications are some of the major poverty-driven factors contributing to antimicrobial resistance. (
  • The antimicrobial resistance of Salmonella isolates was determined using a minimal inhibitory concentration assay with 14 antimicrobials. (
  • Minimum inhibitory concentrations were determined for 17 antimicrobials that are monitored by the National Antimicrobial Resistance Monitoring System. (
  • Antimicrobial resistance in S. aureus has increased dramatically, particularly in the hospital, where the rapid emergence of methicillin-resistant S. aureus (MRSA) and the appearance of S. aureus isolates with resistance to vancomycin have led to concern that this organism may become untreatable with currently available antimicrobials. (
  • Results -Resistance to 1 or more antimicrobials was detected in 986 of 1,441 (68.4%) isolates recovered. (
  • Episome-mediated transfer of drug resistance in Enterobacteriaceae. (
  • The report also includes a summary on the status of drug resistance for TB, HIV and malaria. (
  • Antimicrobial resistance is a worldwide problem that has deleterious long-term effects as the development of drug resistance outpaces the development of new drugs. (
  • Three mechanisms of resistance to chloramphenicol are known: reduced membrane permeability, mutation of the 50S ribosomal subunit, and elaboration of chloramphenicol acetyltransferase. (
  • this gene codes for an enzyme called chloramphenicol acetyltransferase, which inactivates chloramphenicol by covalently linking one or two acetyl groups, derived from acetyl-S-coenzyme A, to the hydroxyl groups on the chloramphenicol molecule. (
  • This family consists of chloramphenicol (Cm) resistance gene leader peptides. (
  • Ribosome stalling in the leader causes the destabilization of the downstream secondary structure, allowing initiation of translation of the Cm resistance gene. (
  • This allele is a protein fusion to the Venus YFP followed by the chloramphenicol resistance gene cat under its own promoter. (
  • S. aureus isolates were screened for methicillin resistance following the NCCLS disk diffusion method. (
  • This article delves into the fascinating world of Chloramphenicol Test Fluorescence , exploring its mechanism of action, historical significance, applications, and potential drawbacks. (
  • The acetylation prevents chloramphenicol from binding to the ribosome. (
  • In translation attenuation, the ribosome-binding-site (RBS) for the resistance determinant is sequestered in a secondary structure domain within the mRNA. (
  • Chloramphenicol was discovered after being isolated from Streptomyces venezuelae in 1947. (
  • Chloramphenicol chemically is D-(-)-threo-1- p- nitrol-phenyl-2-dichloroacetamido 1,3-propanediol ( Figure 36.1 ), has a pK a of 5.5, and was first isolated from the soil organism Streptomyces venezuelae in 1947. (
  • After the discovery of chloramphenicol in 1947 it was in popular use decades ago, but has been gradually replaced by safer alternatives. (
  • The level of intrinsic resistance to both chloramphenicol and tetracycline was increased about twofold. (
  • Resistance-conferring mutations of the 50S ribosomal subunit are rare. (
  • However, the cost of resistance can be mitigated by compensatory mutations elsewhere in the genome, and therefore the loss of resistance may proceed too slowly to be of practical importance. (
  • It is frequently assumed that such compensatory mutations mitigate the fitness costs of resistance mutations without affecting the level of resistance. (
  • As the range of targets for compensation is much broader, compensatory mutations are more likely than the reversion of resistance mutations. (
  • If compensatory mutations are indeed widespread, pathogens can reach both high level of resistance and high fitness. (
  • During the last decade chloramphenicol has been re-evaluated as an old agent with potential against systemic infections due to multidrug-resistant gram positive microorganisms (including vancomycin resistant enterococci). (
  • Although some species are inherently resistant to vancomycin, they are far less common than species that acquire resistance through transfer of genetic material. (
  • Detection of an inducible membrane protein associated with R-factor-mediated tetracycline resistance. (
  • Chloramphenicol inhibits protein synthesis. (
  • identified 'super' variants of the Cfr protein that lead to greater resistance. (
  • Azithromycin epidemiologic cutoff values for wild-type (MIC ≤8 mg/L) and non-wild-type (MIC ≥16 mg/L) Shigella flexneri ( 2 ) and the susceptibility and resistance breakpoints for the other 11 antimicrobial agents were CLSI Enterobacteriaceae breakpoints ( 2 ). (
  • The original indication of chloramphenicol was in the treatment of typhoid, but the presence of multiple drug-resistant Salmonella typhi has meant it is seldom used for this indication except when the organism is known to be sensitive. (
  • The prevalence of antimicrobial resistance in zoonotic Salmonella is a significant ongoing concern over the world. (
  • The epidemiology and antimicrobial resistance pat- induce self-limiting diarrhoea, which is referred to tern of iNTS in Asia is not well documented, with limited as non-typhoidal Salmonella (NTS) gastroenteritis. (
  • The major route of resistance is modification of the 23S rRNA in the 50S ribosomal subunit to insensitivity while efflux can also be significant. (
  • The cytoplasmic inheritance of human chloramphenicol (cap) resistance has been demonstrated by removing the nuclei of cells of the CAP-resistant HeLa strain 296-1 (enucleation) and fusing them to a CAP-sensitive HeLa strain lacking nuclear thymidine kinase. (
  • The study agreed to a large extent with other literature investigating the emergence of antimicrobial resistance in reptiles. (
  • Many formulations have been removed from the commercial market because chloramphenicol no longer is in wide use for humans. (
  • We select our positive ligation products by transforming into destination plasmids or cells with a resistance different from that of the inserts, so this was a problem. (
  • Figure 36.1 The chemical structure of chloramphenicol and modifications to form florfenicol. (
  • Topical formulations of chloramphenicol have been used for otic and ophthalmic use, but the otic formulations have been replaced by newer forms containing florfenicol. (
  • Characterizing the distribution of regionally specific patterns of resistance is important to contextualize and develop locally relevant interventions. (

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