CephalosporinaseCitrobacter: A genus of gram-negative, rod-shaped enterobacteria that can use citrate as the sole source of carbon.beta-Lactamases: Enzymes found in many bacteria which catalyze the hydrolysis of the amide bond in the beta-lactam ring. Well known antibiotics destroyed by these enzymes are penicillins and cephalosporins.Penicillinase: A beta-lactamase preferentially cleaving penicillins. (Dorland, 28th ed) EC 3.5.2.-.Cloxacillin: A semi-synthetic antibiotic that is a chlorinated derivative of OXACILLIN.Cephalosporins: A group of broad-spectrum antibiotics first isolated from the Mediterranean fungus ACREMONIUM. They contain the beta-lactam moiety thia-azabicyclo-octenecarboxylic acid also called 7-aminocephalosporanic acid.Enterobacter: Gram-negative gas-producing rods found in feces of humans and other animals, sewage, soil, water, and dairy products.beta-Lactams: Four-membered cyclic AMIDES, best known for the PENICILLINS based on a bicyclo-thiazolidine, as well as the CEPHALOSPORINS based on a bicyclo-thiazine, and including monocyclic MONOBACTAMS. The BETA-LACTAMASES hydrolyze the beta lactam ring, accounting for BETA-LACTAM RESISTANCE of infective bacteria.Hafnia alvei: The type species for the genus HAFNIA. It is distinguished from other biochemically similar bacteria by its lack of acid production on media containing sucrose. (From Bergey's Manual of Determinative Bacteriology, 9th ed)Proteus vulgaris: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria that occurs in soil, fecal matter, and sewage. It is an opportunistic pathogen and causes cystitis and pyelonephritis.Enterobacter cloacae: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria that occurs in water, sewage, soil, meat, hospital environments, and on the skin and in the intestinal tract of man and animals as a commensal.Cephaloridine: A cephalosporin antibiotic.Penicillanic Acid: A building block of penicillin, devoid of significant antibacterial activity. (From Merck Index, 11th ed)Ceftazidime: Semisynthetic, broad-spectrum antibacterial derived from CEPHALORIDINE and used especially for Pseudomonas and other gram-negative infections in debilitated patients.Cefoxitin: A semisynthetic cephamycin antibiotic resistant to beta-lactamase.Citrobacter freundii: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria found in humans and other animals including MAMMALS; BIRDS; REPTILES; and AMPHIBIANS. It has also been isolated from SOIL and WATER as well as from clinical specimens such as URINE; THROAT; SPUTUM; BLOOD; and wound swabs as an opportunistic pathogen.Anti-Bacterial Agents: Substances that reduce the growth or reproduction of BACTERIA.Microbial Sensitivity Tests: Any tests that demonstrate the relative efficacy of different chemotherapeutic agents against specific microorganisms (i.e., bacteria, fungi, viruses).Aztreonam: A monocyclic beta-lactam antibiotic originally isolated from Chromobacterium violaceum. It is resistant to beta-lactamases and is used in gram-negative infections, especially of the meninges, bladder, and kidneys. It may cause a superinfection with gram-positive organisms.Sulbactam: A beta-lactamase inhibitor with very weak antibacterial action. The compound prevents antibiotic destruction of beta-lactam antibiotics by inhibiting beta-lactamases, thus extending their spectrum activity. Combinations of sulbactam with beta-lactam antibiotics have been used successfully for the therapy of infections caused by organisms resistant to the antibiotic alone.beta-Lactam Resistance: Nonsusceptibility of bacteria to the action of the beta-lactam antibiotics. Mechanisms responsible for beta-lactam resistance may be degradation of antibiotics by BETA-LACTAMASES, failure of antibiotics to penetrate, or low-affinity binding of antibiotics to targets.Cephalosporin Resistance: Non-susceptibility of an organism to the action of the cephalosporins.Isoelectric Focusing: Electrophoresis in which a pH gradient is established in a gel medium and proteins migrate until they reach the site (or focus) at which the pH is equal to their isoelectric point.Drug Resistance, Microbial: 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).Enterobacter aerogenes: Gram-negative, capsulated, gas-producing rods found widely in nature. Both motile and non-motile strains exist. The species is closely related to KLEBSIELLA PNEUMONIAE and is frequently associated with nosocomial infectionsProteus: A genus of gram-negative, facultatively anaerobic, rod-shaped bacteria that occurs in the intestines of humans and a wide variety of animals, as well as in manure, soil, and polluted waters. Its species are pathogenic, causing urinary tract infections and are also considered secondary invaders, causing septic lesions at other sites of the body.Hydrolysis: The process of cleaving a chemical compound by the addition of a molecule of water.Clavulanic Acid: Clavulanic acid and its salts and esters. The acid is a suicide inhibitor of bacterial beta-lactamase enzymes from Streptomyces clavuligerus. Administered alone, it has only weak antibacterial activity against most organisms, but given in combination with other beta-lactam antibiotics it prevents antibiotic inactivation by microbial lactamase.Moxalactam: Broad- spectrum beta-lactam antibiotic similar in structure to the CEPHALOSPORINS except for the substitution of an oxaazabicyclo moiety for the thiaazabicyclo moiety of certain CEPHALOSPORINS. It has been proposed especially for the meningitides because it passes the blood-brain barrier and for anaerobic infections.Imipenem: Semisynthetic thienamycin that has a wide spectrum of antibacterial activity against gram-negative and gram-positive aerobic and anaerobic bacteria, including many multiresistant strains. It is stable to beta-lactamases. Clinical studies have demonstrated high efficacy in the treatment of infections of various body systems. Its effectiveness is enhanced when it is administered in combination with CILASTATIN, a renal dipeptidase inhibitor.Escherichia coli: 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.Serratia marcescens: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria found in soil, water, food, and clinical specimens. It is a prominent opportunistic pathogen for hospitalized patients.Cefotaxime: Semisynthetic broad-spectrum cephalosporin.Pseudomonas aeruginosa: A species of gram-negative, aerobic, rod-shaped bacteria commonly isolated from clinical specimens (wound, burn, and urinary tract infections). It is also found widely distributed in soil and water. P. aeruginosa is a major agent of nosocomial infection.Clavulanic Acids: Acids, salts, and derivatives of clavulanic acid (C8H9O5N). They consist of those beta-lactam compounds that differ from penicillin in having the sulfur of the thiazolidine ring replaced by an oxygen. They have limited antibacterial action, but block bacterial beta-lactamase irreversibly, so that similar antibiotics are not broken down by the bacterial enzymes and therefore can exert their antibacterial effects.Enterobacteriaceae: A family of gram-negative, facultatively anaerobic, rod-shaped bacteria that do not form endospores. Its organisms are distributed worldwide with some being saprophytes and others being plant and animal parasites. Many species are of considerable economic importance due to their pathogenic effects on agriculture and livestock.Thienamycins: Beta-lactam antibiotics that differ from PENICILLINS in having the thiazolidine sulfur atom replaced by carbon, the sulfur then becoming the first atom in the side chain. They are unstable chemically, but have a very broad antibacterial spectrum. Thienamycin and its more stable derivatives are proposed for use in combinations with enzyme inhibitors.Acinetobacter baumannii: A species of gram-negative, aerobic bacteria, commonly found in the clinical laboratory, and frequently resistant to common antibiotics.Enzyme Induction: An increase in the rate of synthesis of an enzyme due to the presence of an inducer which acts to derepress the gene responsible for enzyme synthesis.Genes, Bacterial: The functional hereditary units of BACTERIA.Acinetobacter: A genus of gram-negative bacteria of the family MORAXELLACEAE, found in soil and water and of uncertain pathogenicity.Plasmids: 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.Penicillin G: A penicillin derivative commonly used in the form of its sodium or potassium salts in the treatment of a variety of infections. It is effective against most gram-positive bacteria and against gram-negative cocci. It has also been used as an experimental convulsant because of its actions on GAMMA-AMINOBUTYRIC ACID mediated synaptic transmission.Carbapenems: A group of beta-lactam antibiotics in which the sulfur atom in the thiazolidine ring of the penicillin molecule is replaced by a carbon atom. THIENAMYCINS are a subgroup of carbapenems which have a sulfur atom as the first constituent of the side chain.Enterobacteriaceae Infections: Infections with bacteria of the family ENTEROBACTERIACEAE.Gram-Negative Bacteria: Bacteria which lose crystal violet stain but are stained pink when treated by Gram's method.Kinetics: The rate dynamics in chemical or physical systems.Molecular Sequence Data: 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.Klebsiella pneumoniae: Gram-negative, non-motile, capsulated, gas-producing rods found widely in nature and associated with urinary and respiratory infections in humans.Chromosomes, Bacterial: Structures within the nucleus of bacterial cells consisting of or containing DNA, which carry genetic information essential to the cell.Bacterial Proteins: Proteins found in any species of bacterium.AmidohydrolasesCloning, Molecular: 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.Penicillins: A group of antibiotics that contain 6-aminopenicillanic acid with a side chain attached to the 6-amino group. The penicillin nucleus is the chief structural requirement for biological activity. The side-chain structure determines many of the antibacterial and pharmacological characteristics. (Goodman and Gilman's The Pharmacological Basis of Therapeutics, 8th ed, p1065)DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.

Cloning, sequence analyses, expression, and distribution of ampC-ampR from Morganella morganii clinical isolates. (1/225)

Shotgun cloning experiments with restriction enzyme-digested genomic DNA from Morganella morganii 1, which expresses high levels of cephalosporinase, into the pBKCMV cloning vector gave a recombinant plasmid, pPON-1, which encoded four entire genes: ampC, ampR, an hybF family gene, and orf-1 of unknown function. The deduced AmpC beta-lactamase of pI 7.6 shared structural and functional homologies with AmpC from Citrobacter freundii, Escherichia coli, Yersinia enterocolitica, Enterobacter cloacae, and Serratia marcescens. The overlapping promoter organization of ampC and ampR, although much shorter in M. morganii than in the other enterobacterial species, suggested similar AmpR regulatory properties. The MICs of beta-lactams for E. coli MC4100 (ampC mutant) harboring recombinant plasmid pACYC184 containing either ampC and ampR (pAC-1) or ampC (pAC-2) and induction experiments showed that the ampC gene of M. morganii 1 was repressed in the presence of ampR and was activated when a beta-lactam inducer was added. Moreover, transformation of M. morganii 1 or of E. coli JRG582 (delta ampDE) harboring ampC and ampR with a recombinant plasmid containing ampD from E. cloacae resulted in a decrease in the beta-lactam MICs and an inducible phenotype for M. morganii 1, thus underlining the role of an AmpD-like protein in the regulation of the M. morganii cephalosporinase. Fifteen other M. morganii clinical isolates with phenotypes of either low-level inducible cephalosporinase expression or high-level constitutive cephalosporinase expression harbored the same ampC-ampR organization, with the hybF and orf-1 genes surrounding them; the organization of these genes thus differed from those of ampC-ampR genes in C. freundii and E. cloacae, which are located downstream from the fumarate operon. Finally, an identical AmpC beta-lactamase (DHA-1) was recently identified as being plasmid encoded in Salmonella enteritidis, and this is confirmatory evidence of a chromosomal origin of the plasmid-mediated cephalosporinases.  (+info)

Clavulanate induces expression of the Pseudomonas aeruginosa AmpC cephalosporinase at physiologically relevant concentrations and antagonizes the antibacterial activity of ticarcillin. (2/225)

Although previous studies have indicated that clavulanate may induce AmpC expression in isolates of Pseudomonas aeruginosa, the impact of this inducer activity on the antibacterial activity of ticarcillin at clinically relevant concentrations has not been investigated. Therefore, a study was designed to determine if the inducer activity of clavulanate was associated with in vitro antagonism of ticarcillin at pharmacokinetically relevant concentrations. By the disk approximation methodology, clavulanate induction of AmpC expression was observed with 8 of 10 clinical isolates of P. aeruginosa. Quantitative studies demonstrated a significant induction of AmpC when clavulanate-inducible strains were exposed to the peak concentrations of clavulanate achieved in human serum with the 3.2- and 3.1-g doses of ticarcillin-clavulanate. In studies with three clavulanate-inducible strains in an in vitro pharmacodynamic model, antagonism of the bactericidal effect of ticarcillin was observed in some tests with regimens simulating a 3.1-g dose of ticarcillin-clavulanate and in all tests with regimens simulating a 3.2-g dose of ticarcillin-clavulanate. No antagonism was observed in studies with two clavulanate-noninducible strains. In contrast to clavulanate. No antagonism was observed in studies with two clavulanate-noninducible strains. In contrast to clavulanate, tazobactam failed to induce AmpC expression in any strains, and the pharmacodynamics of piperacillin-tazobactam were somewhat enhanced over those of piperacillin alone against all strains studied. Overall, the data collected from the pharmacodynamic model suggested that induction per se was not always associated with reduced killing but that a certain minimal level of induction by clavulanate was required before antagonism of the antibacterial activity of its companion drug occurred. Nevertheless, since clinically relevant concentrations of clavulanate can antagonize the bactericidal activity of ticarcillin, the combination of ticarcillin-clavulanate should be avoided when selecting an antipseudomonal beta-lactam for the treatment of P. aeruginosa infections, particularly in immunocompromised patients. For piperacillin-tazobactam, induction is not an issue in the context of treating this pathogen.  (+info)

In vitro antibacterial activity of FK041, a new orally active cephalosporin. (3/225)

The in vitro activity of FK041, a new orally active cephem antibiotic, against a wide variety of clinical isolates of bacteria was investigated and compared with those of cefdinir (CFDN) and cefditoren (CDTR). FK041 exhibited broad spectrum activity against reference strains of Gram-positive and Gram-negative aerobes and anaerobes. FK041 was active against clinical isolates of Gram-positive organisms except Enterococcus faecalis with MIC90s less than 1.56 microg/ml. FK041 was more active than CFDN and CDTR against Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus agalactiae and was comparable to CFDN and CDTR against Streptococcus pyogenes and Streptococcus pneumoniae. FK041 had no activity against methicillin-resistant staphylococci, like CFDN and CDTR. FK041 showed moderate activity against penicillin-resistant S. pneumoniae with an MIC range of 0.05 approximately 3.13 microg/ml, and was superior to CFDN but inferior to CDTR. Against clinical isolates of many Gram-negative organisms such as Neisseria gonorrhoeae, Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis, FK041 had good activity comparable or superior to those of CFDN and CDTR. However, it was inferior to CDTR in activity against Moraxella catarrhalis, Haemophilus influenzae, Morganella morganii, and Serratia marcescens, and was inactive against Pseudomonas aeruginosa. With FK041 a small difference between MIC and MBC against S. aureus, E. coli, K. pneumoniae, and H. influenzae was found, indicating that its action is bactericidal against these species. FK041 was stable to group 2beta-lactamase hydrolysis but was unstable to group 1beta-lactamase hydrolysis. The stability of FK041 to these enzymes was similar to those of CFDN and CDTR. FK041 showed high affinity for the main penicillin-binding proteins (PBPs) of S. aureus (PBP 3, 2, and 1) and E. coli (PBP 3, 4, lbs, 2, and 1a).  (+info)

Rapid detection of ampicillin-resistant Haemophilus influenzae and their susceptibility to sixteen antibiotics. (4/225)

Ampicillin-resistant and -susceptible strains of Haemophilus influenzae were tested for susceptibility to 16 antibiotics. Chloramphenicol and a new cephalosporin, cefamandole, were most active with minimal inhibitory concentrations (MICs) for all bacteria tested between 0.5 to 2.0 mug/ml. All but two organisms were susceptible to tetracycline. Ampicillin-resistant strains of H. influenzae were less susceptible (MIC, 4 to 32 mug/ml) to carbenicillin and ticarcillin than ampicillin-susceptible organisms (MIC, 0.25 to 1.0 mug/ml). A rapid assay for beta-lactamase, utilizing a chromogenic cephalosporin substrate, detected enzyme production in all 17 ampicillin-resistant strains of H. influenzae.  (+info)

R-factor mediated beta-lactamase production by Haemophilus influenzae. (5/225)

Production of beta-lactamase by 15 strains of Haemophilus influenzae has been investigated. All the strains produce a constitutive beta-lactamase, which readily hydrolyses penicillin G, ampicillin, and cephaloridine. The beta-lactamase produced by these strains is indistinguishable from the type-IIIa enzyme commonly found in strains of Escherichia coli. The beta-lactamase gene has been transferred from the enzyme-producing strains of Haemophilus to strains of H. parainfluenzae and a strain of E. coli.  (+info)

Biochemical-genetic characterization and regulation of expression of an ACC-1-like chromosome-borne cephalosporinase from Hafnia alvei. (6/225)

A naturally occurring AmpC beta-lactamase (cephalosporinase) gene was cloned from the Hafnia alvei 1 clinical isolate and expressed in Escherichia coli. The deduced AmpC beta-lactamase (ACC-2) had a pI of 8 and a relative molecular mass of 37 kDa and showed 50 and 47% amino acid identity with the chromosome-encoded AmpCs from Serratia marcescens and Providentia stuartii, respectively. It had 94% amino acid identity with the recently described plasmid-borne cephalosporinase ACC-1 from Klebsiella pneumoniae, suggesting the chromosomal origin of ACC-1. The hydrolysis constants (k(cat) and K(m)) showed that ACC-2 was a peculiar cephalosporinase, since it significantly hydrolyzed cefpirome. Once its gene was cloned and expressed in E. coli (pDEL-1), ACC-2 conferred resistance to ceftazidime and cefotaxime but also an uncommon reduced susceptibility to cefpirome. A divergently transcribed ampR gene with an overlapping promoter compared with ampC (bla(ACC-2)) was identified in H. alvei 1, encoding an AmpR protein that shared 64% amino acid identity with the closest AmpR protein from P. stuartii. beta-Lactamase induction experiments showed that the ampC gene was repressed in the absence of ampR and was activated when cefoxitin or imipenem was added as an inducer. From H. alvei 1 cultures that expressed an inducible-cephalosporinase phenotype, several ceftazidime- and cefpirome-cross-resistant H. alvei 1 mutants were obtained upon selection on cefpirome- or ceftazidime-containing plates, and H. alvei 1 DER, a ceftazidime-resistant mutant, stably overproduced cephalosporinase. Transformation of H. alvei 1 DER or E. coli JRG582 (ampDE mutant) harboring ampC and ampR from H. alvei 1 with a recombinant plasmid containing ampD from E. coli resulted in a decrease in the MIC of beta-lactam and recovery of an inducible phenotype for H. alvei 1 DER. Thus, AmpR and AmpD proteins may regulate biosynthesis of the H. alvei cephalosporinase similarly to other enterobacterial cephalosporinases.  (+info)

The high resolution crystal structure for class A beta-lactamase PER-1 reveals the bases for its increase in breadth of activity. (7/225)

The treatment of infectious diseases by beta-lactam antibiotics is continuously challenged by the emergence and dissemination of new beta-lactamases. In most cases, the cephalosporinase activity of class A enzymes results from a few mutations in the TEM and SHV penicillinases. The PER-1 beta-lactamase was characterized as a class A enzyme displaying a cephalosporinase activity. This activity was, however, insensitive to the mutations of residues known to be critical for providing extended substrate profiles to TEM and SHV. The x-ray structure of the protein, solved at 1.9-A resolution, reveals that two of the most conserved features in class A beta-lactamases are not present in this enzyme: the fold of the Omega-loop and the cis conformation of the peptide bond between residues 166 and 167. The new fold of the Omega-loop and the insertion of four residues at the edge of strand S3 generate a broad cavity that may easily accommodate the bulky substituents of cephalosporin substrates. The trans conformation of the 166-167 bond is related to the presence of an aspartic acid at position 136. Selection of class A enzymes based on the occurrence of both Asp(136) and Asn(179) identifies a subgroup of enzymes with high sequence homology.  (+info)

Relation of beta-lactamase activity to antimicrobial susceptibility in Serratia marcescens. (8/225)

One-hundred clinical isolates of Serratia marcescens were tested for susceptibility to cephalothin, carbenicillin, ticarcillin, ampicillin, and cefoxitin. The majority of the 100 isolates (>/=70%) were susceptible to carbenicillin, ticarcillin, and cefoxitin; less than one-half were susceptible to ampicillin; none were susceptible to cephalothin. Ten isolates from the 100 organisms tested were selectively assayed for their beta-lactamase activity. Enzyme activity was measured using either iodometric or spectrophotometric methods, and the microbiological assay technique. It was concluded that beta-lactamase production was not the sole determinant in beta-lactam antibiotic resistance. Resistance without demonstrable beta-lactamase was evident in strains for cephalothin, ampicillin, and cefoxitin. In addition, one strain which was susceptible to all antibiotics except cephalothin, elaborated considerable beta-lactamase activity.  (+info)

A 1536-nucleotide-long sequence that carries the ampC beta-lactamase gene of the Escherichia coli K-12 chromosome has been determined. This gene codes for a protein of 377 amino acids, of which the first 19 amino acids form a signal peptide. The molecular weight of the mature enzyme was determined to be 39,600. The ampC beta-lactamase with a substrate specificity for cephalosporins showed no significant sequence homologies with beta-lactamases of the penicillinase type or with D-alanine carboxypeptidases. However, because the region around serine-80 of the ampC beta-lactamase has extensive homology with an active-site fragment of the Pseudomonas aeruginosa cephalosporinase, we suggest that the ampC cephalosporinase as well as related cephalosporinases form a distinct group of serine beta-lactamases that have an evolutionary origin different from that of the serine penicillinases and thus constitute a new class of beta-lactamases.. ...
Looking for cephalosporinase? Find out information about cephalosporinase. A bacterial enzyme that catalyzes the hydrolysis of the lactam ring in some penicillin antibiotics, rendering them ineffective Explanation of cephalosporinase
PubMed comprises more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
In this study of the diversity of AmpC beta-lactamase in clinical isolates of Enterobacter spp., a strain was found carrying the plasmid-mediated AmpC beta-lactamase ACT-1 gene on its chromosome. The strain was identified as Enterobacter hormaechei using phylogenetic analysis of 16S rRNA and hsp60 genes. In addition, the species was confirmed by DNA DNA hybridization. The genetic environment of the bla(ACT-1) gene was characterized, including the ampR and ampG genes, using a two-step PCR. The amino acid sequences of AmpR at serine 35, arginine 86, glycine 102, aspartic acid 135 and tyrosine 264 were conserved. Measurement of the transcription level of the bla(ACT-1), gene using real-time quantitative PCR showed that it increased 1.98-fold following cefoxitin induction. These results suggest that the plasmid-mediated bla(ACT-1) gene originated from the chromosome of E. hormaechei ...
Amino acid changes that influence activity and resistance to beta-lactams and beta-lactamase inhibitors were explored by constructing the Gly238Ser and Met69Ile-Gly238Ser mutants of the OHIO-1 beta-lactamase, a class A enzyme of the SHV family. The Km values of cefotaxime and ceftazidime for OHIO-1 and Met69Ile beta-lactamases were , or = 500 microM. The Km of cefotaxime for the Gly238Ser beta-lactamase was 26 microM, and that of ceftazidime was 105 microM. The Km of cefotaxime for the Met69Ile-Gly238Ser beta-lactamase was 292 microM, and that of ceftazidime was 392 microM. For the beta-lactamase inhibitors clavulanate and sulbactam, the apparent Ki values for the Met69Ile-Gly238Ser enzyme were 0.03 and 0.15 microM, respectively. Relative Vmax values indicate that the Met69Ile-Gly238Ser mutant of the OHIO-1 beta-lactamase possesses cephalosporinase activity similar to that of the Gly238Ser mutant but diminished penicillinase activity. In an Escherichia coli DH5alpha strain that possesses a ...
Pseudomonas aeruginosa AH, isolated in Ankara, Turkey, was highly resistant to ceftazidime (MIC, 128 microg/ml) and produced a beta-lactamase that gave a doublet of bands at pIs 8.7 and 8.9. beta-Lactamase production was transferable to P. aeruginosa PU21 by conjugation and was determined by a ca. 450-kb plasmid, pMLH54. The transconjugant and Escherichia coli transformed with the cloned gene showed increased resistance to ceftazidime (especially) and to cefpirome, ceftazidime, ceftriaxone, moxalactam, and aztreonam, but not to carbapenems. Resistance was not reversed by clavulanic acid or tazobactam. Sequencing revealed that the beta-lactamase responsible for this resistance was identical to OXA-2 except that glycine replaced aspartate at position 150. Compared to OXA-2, the new enzyme, named OXA-15, had greater cephalosporinase activity, with increased relative hydrolysis rates for cephaloridine and cephalothin and, most dramatically, for ceftazidime. Cefotaxime and carbapenems remained stable ...
NDM-1 (New Delhi metallo-beta-lactamase) gene encodes a metallo-beta-lactamase (MBL) with high carbapenemase activity, which makes the host bacterial strain easily dispatch the last-resort antibiotics
Chromosomal ampC genes in Enterobacter species other than Enterobacter cloacae, and ancestral association of the ACT-1 plasmid-encoded cephalosporinase to Enterobacter ...
In recent years, bacterial drug resistance increased gravity with applied of P-lactam antibiotics widely. Extended Spectrum P-Lactamase (ESBLs) and Amp Cephalosporinase (AmpC enzyme) were the major
Ceftazidime is the antibiotic of choice for treatment of Burkholderia pseudomallei infections (melioidosis). The chromosomally encoded PenA β-lactamase possesses weak cephalosporinase activity. The wild-type penA gene confers clinically significant ceftazidime resistance only when overexpressed due to a promoter mutation, transcriptional anti-termination or by gene duplication and amplification (GDA). Here we characterize a reversible 33-kb GDA event involving wild-type penA in a ceftazidime resistant clinical isolate from Thailand. We show that duplication arises from exchanges between short (|10 base pairs, bp) chromosomal sequences, which in this example consist of 4 bp repeats flanked by 3 bp inverted repeats. GDA involving β-lactamase may be a common ceftazidime resistance mechanism in B. pseudomallei.
PubMed comprises more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
Background -lactam level of resistance in Gram-negative bacteria is a substantial clinical issue in the grouped community, long-term care services, and hospitals. fast and accurate approach to visualizing the SHV category of enzymes in medical examples including Gram-negative bacilli utilizing a fluorescein-labeled polyclonal antibody. Background Level of resistance to -lactam antibiotics in Gram-negative bacterias can be a Volasertib substantial medical issue in the grouped community, long-term treatment, and hospital configurations [1-3]. In the normal Gram-negative bacterias that are in charge of most medical infections, -lactam level of resistance results from creation of penicillinases (mainly the -lactamases specified TEM-1 and SHV-1), cephalosporinases (e.g., extended-spectrum -lactamases, ESBL, of TEM-, SHV- and CTX-M-types), as well as the plasmid or chromosomally encoded AmpC enzymes [1]. Hence, an intense search for book therapeutic real estate agents and fast, accurate detection ...
Dr. Menchell responded: Cephalosporin rx. Older studies suggested that there was a 5-7% risk of having a reaction to a cephalosporin if you had a history of |a href="/topics/penicillin-allergy" track_data="{
A new series of phosphonyl derivatives has been prepared and tested for inhibition of serine (classes A and C) beta-lactamases. The results were compared with those previously acquired with aryl phosphonate monoesters and with alkaline hydrolysis rates. A methyl p-nitrophenyl phosphate monoanion was markedly poorer as an inhibitor of the class C beta-lactamase of Enterobacter cloacae P99 than a comparable p-nitrophenyl phosphonate. Phosphonyl fluorides, thiophenyl esters, N-phenylphosphonamidates and a p-nitrophenyl thionophosphonate were, in general, comparable with p-nitrophenyl phosphonates in inhibitory power. The incorporation of a specific amino side chain led to an increase in the rates of inhibition of around 10(4)-fold. Apparently unresponsive to the addition of the side chain to the enzyme was N-phenyl methylphosphonamidate, where binding of the side chain may interfere with access of the leaving group to a proton which is necessary to active-site phosphonylation and inhibition. ...
第5世代まであるぞ cephalosporins 第5世代もはやスターウォーズcephalosporins 第3世代経口は察し cephalosporins 風邪にはきかない cephalosporins 採用ミニマリスト目指そう cephalosporins UpToDate
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1GCE: Structure of the extended-spectrum class C beta-lactamase of Enterobacter cloacae GC1, a natural mutant with a tandem tripeptide insertion.
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Cephalosporins: an update.: The cephalosporins are the largest and most diverse family of antimicrobial agents available. Although they rarely are considered dr
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... ,(3alpha,4alpha,6alpha,7beta,8alpha,9beta,13alpha,14beta,16beta,17Z)-6,16-Bis(acetyloxy)-3,7-dihydroxy-29-nordammara-17(20),24-dien-21-oic acid
HPLC Application #16908: Polar-RP - Cephalosporins. Column used: Synergi™ 4 µm Polar-RP 80 Å, LC Column 150 x 4.6 mm, Ea Part#: 00F-4336-E0
Despite the unfavorable double-room configuration of our ICU, the 4.1% rate of ESBL acquisition was much lower than the 13% reported by Razazi et al. in a 24-bed ICU with eight single rooms but without any protocol of contact precautions for ESBL carriers [13]. It is close to that reported by Alves et al. in an ICU with only single rooms, in which contact precautions were also applied [17]. Unlike Barbier et al., who reported that half of the ESBL carriers acquired their ESBL during their ICU stay [16], and Gardam et al., who reported that ESBL acquisition accounted for two-thirds of ESBL carriage in the ICU [18], ESBL acquisition accounted for only 12.7% of all ESBL carriage in our study, confirming that ESBL carriage is mostly imported, whereas high-level cephalosporinase (HL-Case) is mostly acquired, in the ICU [19]. In multivariate analysis, the severity (SAPS II) at admission was the only factor identified to be associated with the acquired carriage of ESBL, while some authors have reported ...
Citrobacter freundii appear as Gram-negative, rod-shaped bacteria that are 0.3-1 micrometer in diameter and 0.6-6 micrometers in length. Citrobacter have hair-like extensions, called flagella, that...
do you know any links/sites i can use as a reference or any info on citrobacter freundii that are scientific resources? im doing a microbiology research profile ...
The new cephalosporin compounds have increased in vitro activity against gram-negative enteric bacilli and penetrate well into cerebrospinal fluid. Moreover, their pharmacokinetic properties are favorable and their safety seems adequate, although ins
Biological systems have evolved to harness non-equilibrium processes from the molecular to the macro scale. It is currently a grand challenge of chemistry, materials science, and engineering to understand and mimic biological systems that have the ability to autonomously sense stimuli, process these inputs, Chemical systems out of equilibrium
Product Name: Ceftriaxone Sulbactam Injection Common Name: antibiotic injection. Strength: 1.5gm. Description: Ceftriaxone is a broad-spectrum semi-synthetic third-generation cephalosporin with a potent bactericidal activity against a wide range of gram-positive and gram-negative bacteria. Sulbactam is ß- lactamase inhibitor. Ceftriaxone is a bactericidal agent that acts by inhibition of bacterial cell wall synthesis. Ceftriaxone has activity in the presence of some beta-lactamases, both penicillinases and cephalosporinases, of Gram-negative and Gram-positive bacteria.. Indications and Usage:. Ceftriaxone Injection is used to cure below mentioned infections:. ...
E coli beta-lactamase LAT-3 protein: C-class beta-lactamase from cefoxitin-resistant Escherichia coli; closely related to AmpC beta-lactamase; GenBank Y15411
Looking for Cephalosporins? Find out information about Cephalosporins. a group of natural and semisynthetic antibiotics with similar chemical structures and biological properties. Natural cephalosporins-cephalosporin C and... Explanation of Cephalosporins
beta-lactamase definition: See penicillinase.; An enzyme made by particular bacteria, in charge of their opposition to beta-lactam antibiotics such as penicillin.; chemical made by particular germs that…
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But if its your first year in pharmacology, its a lot to take in. I did make some memory aids for studying generations of cephalosporins but after a while, I promise you wont need them ...
CepA (Chromosomal cephalosporinase from Bacteroides fragilis belonging to Ambler class A) is an endogenous cephalosporinase A ... Cloning and characterization of the endogenous cephalosporinase gene, cepA, from Bacteroides fragilis reveals a new subgroup of ... is a specific endogenous cephalosporinase described in B. uniformis, susceptible to clavulanic acid. The homology is 43% ...
... cephalosporinase MeSH D08.811.277.087.180.697 --- penicillinase MeSH D08.811.277.087.200 --- biotinidase MeSH D08.811.277.087. ...
Chromosomal cephalosporinase in Enterobacter hormaechei as an ancestor of ACT-1 plasmid-mediated AmpC beta-lactamase. J. Med. ...
It remains very stable in the presence of β-lactamase (both penicillinase and cephalosporinase) produced by some bacteria, and ...
... is able to inhibit the most common forms of β-lactamase but is not able to interact with the AmpC cephalosporinase. ...
... cephalosporinase. Now included with EC 3.5.2.6 β-lactamase EC 3.5.2.9: 5-oxoprolinase (ATP-hydrolysing) EC 3.5.2.10: ...
ampC cephalosporinase of Escherichia coli K-12 has a different evolutionary origin from that of beta-lactamases of the ... ampC cephalosporinase of Escherichia coli K-12 has a different evolutionary origin from that of beta-lactamases of the ... ampC cephalosporinase of Escherichia coli K-12 has a different evolutionary origin from that of beta-lactamases of the ... ampC cephalosporinase of Escherichia coli K-12 has a different evolutionary origin from that of beta-lactamases of the ...
2. Low occurrence of extended-spectrum cephalosporinase producing Enterobacteriaceae and no detection of methicillin-resistant ...
Biochemical-genetic characterization and regulation of expression of an ACC-1-like chromosome-borne cephalosporinase from ...
Sykes Type 1 Cephalosporinase) beta-lactamases produced by Acinetobacter species, Citrobacter species, Enterobacter, Indole ...
Inactivation of the Pseudomonas-derived cephalosporinase-3 (PDC-3) by relebactam. Antimicrob Agents Chemother 62:e02406-17. doi ... and the Pseudomonas-derived cephalosporinase-3 (PDC-3) enzyme (3.4 μM) (33). ...
Our products can be classified into 10 main therapeutic categories, with particular emphasis on anti-infectives, central nervous system and cardiovascular medication.. In addition to our core branded generics business, we are involved in super-generics and have produced our own patented devices for asthma.. We also produce and market a range of OTC (over-the-counter) products.. ...
... extended-spectrum cephalosporinase (ESC) Escherichia coli and Clostridium difficile. Forty (20%) of the dogs were reported to ...
Extended Spectrum P-Lactamase (ESBLs) and Amp Cephalosporinase (AmpC enzyme) were the major ... Extended Spectrum P-Lactamase (ESBLs) and Amp Cephalosporinase (AmpC enzyme) were the major reason of resistance.Cefbuperazone ...
Effects of the Val211Gly substitution on molecular dynamics of CMY-2 cephalosporinase: implications on hydrolysis of expanded- ... a Val211Gly mutant of CMY-2 cephalosporinase. Antimicrobial Agents and Chemotherapy 2009, 53:3520-3. ...
A chromosomally mediated cephalosporinase, which has mainly cefotaximase activity, inC. amalonaticus has been previously ... theEnterobacter strains Rio-1 and Rio-3 harbored β-lactamases with alkaline pI values consistent with cephalosporinase ...
The invention relates to cephalosporinase gene, a protein containing the amino acid sequence encoded by the specified genome ...
... of the inducible chromosomal cephalosporinase AmpC.16 Another of the mechanisms of mutational resistance is the inactivation of ...
100% of imipenem-resistant strains have both extended-spectrum cephalosporinase (ESAC) overexpression and loss of porin ...
... and 3 were cephalosporinase hyper-producing isolates [Enterobacter cloacae, Serratia odorifera and Hafnia alvei]. Regarding the ...
Co-existence of Pseudomonas-derived cephalosporinase among plasmid encoded CMY-2 harbouring isolates of Pseudomonas aeruginosa ...
... selection and transmission of Extended-Spectrum Cephalosporinase- and Carbapenemase-producing Enterobacteriaceae. ... Proximity to humans was associated with higher occurrence of cephalosporinase (ESBL and pAmpC)-producing E. coli in wild gulls ... The results indicate that transmission of cephalosporinase-producing E. coli/K. pneumoniae occur between wildlife, humans and ... while cephalosporinase-producing E. coli/K. pneumoniae was common in both humans and livestock. The same ESBL/pAmpC genes were ...
Spread of extended spectrum cephalosporinase-producing Escherichia coli clones and plasmids from parent animals to broilers and ...
B. anthracis isolates produce a cephalosporinase (7) that inhibits the antibacterial activity of cephalosporins such as ...
... which encodes a cephalosporinase in all third-generation cephalosporin-resistant isolates. In the genomes of Vibrio cholerae ...
coli by cephalosporinase production was larger in the strain lacking outer membrane proteins (Omp) F and C, and smaller in the ...
The presence of cephalosporinase activity results in specific mass shifts of the antibiotic, evaluated by the MBT STAR®-BL IVD ... Detection of ESBL and AmpC cephalosporinase activity. Together with the IVD MALDI Biotyper®, the MBT STAR®-Cepha IVD Kit ...
Molecular characterization of carbapenemase and cephalosporinase genes among clinical isolates of Acinetobacter baumannii in a ...
... the production of CMY-2 cephalosporinase (86.4%), and decreased expression of the OmpF (97.0%) and/or OmpC (56.1%) porins. No ... the production of CMY-2 cephalosporinase (86.4%), and decreased expression of the OmpF (97.0%) and/or OmpC (56.1%) porins. No ... the production of CMY-2 cephalosporinase (86.4%), and decreased expression of the OmpF (97.0%) and/or OmpC (56.1%) porins. No ... the production of CMY-2 cephalosporinase (86.4%), and decreased expression of the OmpF (97.0%) and/or OmpC (56.1%) porins. No ...
  • On the contrary, ESAC expressed in the OmpC- or OmpF-deficient E. coli strains or narrow-spectrum cephalosporinase expressed in the OmpC-and OmpF-deficient strain do not confer reduced susceptibility to any of the carbapenems. (nih.gov)
  • In Paper V, carbapenem resistant and blaOXA-48 harbouring- E. coli/K. pneumoniae was rare, but present in healthy humans in rural Cambodia, while cephalosporinase-producing E. coli/K. pneumoniae was common in both humans and livestock. (avhandlingar.se)
  • The results indicate that transmission of cephalosporinase-producing E. coli/K. pneumoniae occur between wildlife, humans and livestock, but more in-depth molecular work is needed to determine the mechanisms of dissemination. (avhandlingar.se)
  • RÉSUMÉ L'émergence et la propagation rapide des souches de Klebsiella pneumoniae résistantes aux antibiotiques et porteuses du gène blaKPC codant la production de carbapénèmases ont compliqué la prise en charge des infections des patients. (who.int)
  • This was shown by adding the cephalosporinase-containing OMVs to cultures containing the ampicillin-susceptible gut bacteria, Bifidobacteria breve , which effectively protected them against high concentrations of antibiotics. (healthcanal.com)
  • Treatment binds a cephalosporinase-forming ganglion detumescence anxiety, blood, which, like drug, is cleared from the tangentiality by functions in the respect. (envirosealpipe.co.uk)