Cefsulodin
Cefotiam
Cephalosporins
Mezlocillin
Peptidoglycan Glycosyltransferase
Pseudomonas aeruginosa
beta-Lactams
beta-Lactamases
Fast lysis of Escherichia coli filament cells requires differentiation of potential division sites. (1/46)
Periodic activation of zonal peptidoglycan (murein) synthesis at division sites in Escherichia coli has been reported recently. Zonal synthesis is responsible for septum formation, whereas elongation of the cell sacculus is performed by diffuse insertion of precursors. Zonal synthesis can be triggered in ftsA, ftsQ and ftsI (pbpB) division mutants growing as filaments at the restrictive temperature, but not in ftsZ mutant strains. The lytic response to beta-lactams of cells able or unable to periodically trigger a zonal mode of murein synthesis could be substantially different. Therefore, we investigated the response to the bacteriolytic beta-lactam cefsulodin of ftsZ and ftsI mutants growing at the restrictive (42 degrees C) temperature. The ftsI cells lysed early and quickly after addition of the antibiotic. Sacculi of lysed cells were transversely cut in a very sharp way. In contrast the ftsZ strain lysed late and slowly after addition of the antibiotic and sacculi showed a generalized weakening of the murein network and extended breaks with a frayed appearance. No transversely cut sacculi comparable to those seen in the ftsI samples were found. Our results strongly support that beta-lactam-induced lysis occurs preferentially at division sites because of the activation of zonal murein synthesis at the initiation of septation. (+info)Comparative in vitro activities of SCE-129, sulbenicillin, gentamicin, and dibekacin against Pseudomonas. (2/46)
Against sulbenicillin- and gentamicin-susceptible strains of Pseudomonas aeruginosa, SCE-129 was about 10 times more active than sulbenicillin and had a similar activity to gentamicin and dibekacin. Sulbenicillin-resistant strains of P. aeruginosa were moderately resistant to SCE-129, whether these strains were gentamicin-resistant or not. Gentamicin-resistant strains of P. aeruginosa were resistant to dibekacin but not to SCE-129. Against P. maltophilia, the minimum inhibitory concentration of SCE-129 resembled those of sulbenicillin, gentamicin, and dibekacin. Most strains of P. cepacia were moderately resistant to SCE-129 and sulbenicillin and highly resistant to gentamicin and dibekacin. (+info)Cross-resistance to meropenem, cephems, and quinolones in Pseudomonas aeruginosa. (3/46)
Multiple-drug-resistant mutants were isolated from Pseudomonas aeruginosa PAO1 on agar plates containing ofloxacin and cefsulodin. These mutants were four to eight times more resistant to meropenem, cephems, carbenicillin, quinolones, tetracycline, and chloramphenicol than the parent strain was. In contrast, these mutants showed no significant changes in their susceptibilities to all carbapenems except meropenem. In these mutants, the amounts of an outer membrane protein with an apparent molecular weight of 49,000 (designated OprM) were increased compared with the amount in PAO1. Multiple-drug-resistant mutants of this type were also isolated from PAO1 on agar plates containing meropenem. Approximately 5% of clinical isolates showed cross-resistance to meropenem, cephems, and quinolones, concomitant with overproduction of OprM. Moreover, these two phenotypes, i.e., multiple-drug resistance and overproduction of OprM, were cotransferable by transduction. These data suggest that overproduction of OprM is associated with cross-resistance to meropenem, cephems, and quinolones in P. aeruginosa. The ofloxacin-cefsulodin-resistant mutant required higher concentrations of meropenem to induce beta-lactamase than PAO1 did, indicating the possibility that this mutation involves decreased outer membrane permeability to meropenem. (+info)Unstable Escherichia coli L forms revisited: growth requires peptidoglycan synthesis. (4/46)
Growing bacterial L forms are reputed to lack peptidoglycan, although cell division is normally inseparable from septal peptidoglycan synthesis. To explore which cell division functions L forms use, we established a protocol for quantitatively converting a culture of a wild-type Escherichia coli K-12 strain overnight to a growing L-form-like state by use of the beta-lactam cefsulodin, a specific inhibitor of penicillin-binding proteins (PBPs) 1A and 1B. In rich hypertonic medium containing cefsulodin, all cells are spherical and osmosensitive, like classical L forms. Surprisingly, however, mutant studies showed that colony formation requires d-glutamate, diaminopimelate, and MurA activity, all of which are specific to peptidoglycan synthesis. High-performance liquid chromatography analysis confirmed that these L-form-like cells contain peptidoglycan, with 7% of the normal amount. Moreover, the beta-lactam piperacillin, a specific inhibitor of the cell division protein PBP 3, rapidly blocks the cell division of these L-form-like cells. Similarly, penicillin-induced L-form-like cells, which grow only within the agar layers of rich hypertonic plates, also require d-glutamate, diaminopimelate, and MurA activity. These results strongly suggest that cefsulodin- and penicillin-induced L-form-like cells of E. coli-and possibly all L forms-have residual peptidoglycan synthesis which is essential for their growth, probably being required for cell division. (+info)The Rcs phosphorelay is a cell envelope stress response activated by peptidoglycan stress and contributes to intrinsic antibiotic resistance. (5/46)
(+info)Cell cycle-independent lysis of Escherichia coli by cefsulodin, an inhibitor of penicillin-binding proteins 1a and 1b. (6/46)
Cefsulodin lyses actively growing Escherichia coli by binding specifically to penicillin-binding proteins (PBPs) 1a and 1b. Recent findings (F. Garcia del Portillo, M. A. de Pedro, D. Joseleau-Petit, and R. D'Ari, J. Bacteriol. 171:4217-4221, 1989) have linked cefsulodin-induced lysis to septation during the first division cycle after a nutritional shift-up or chromosome replication realignment. We synchronized cells by membrane filtration to determine whether cefsulodin-induced lysis depended on septation in normally growing cells. Populations of newly divided cells were allowed to grow for variable lengths of time. Cefsulodin was added to these synchronous cultures, which represented points in two to three rounds of the cell cycle. Since the cell numbers were small, a new lysis assay was developed that was based on the release of DNA measured by fluorometry. Lysis occurred at a constant time after addition of the antibiotic, regardless of the time in the cell cycle at which the addition was made. Thus, cefsulodin-induced lysis is not linked to septation or to any other cell cycle-related event. (+info)Lysis of Escherichia coli by beta-lactams which bind penicillin-binding proteins 1a and 1b: inhibition by heat shock proteins. (7/46)
The heat shock proteins (HSPs) of Escherichia coli were artificially induced in cells containing the wild-type rpoH+ gene under control of a tac promoter. At 30 degrees C, expression of HSPs produced cells that were resistant to lysis by cephaloridine and cefsulodin, antibiotics that bind penicillin-binding proteins (PBPs) 1a and 1b. This resistance could be reversed by the simultaneous addition of mecillinam, a beta-lactam that binds PBP 2. However, even in the presence of mecillinam, cells induced to produce HSPs were resistant to lysis by ampicillin, which binds all the major PBPs. Lysis of cells induced to produce HSPs could also be effected by imipenem, a beta-lactam known to lyse nongrowing cells. These effects suggest the existence of at least two pathways for beta-lactam-dependent lysis, one inhibited by HSPs and one not. HSP-mediated lysis resistance was abolished by a mutation in any one of five heat shock genes (dnaK, dnaJ, grpE, GroES, or groEL). Thus, resistance appeared to depend on the expression of the complete heat shock response rather than on any single HSP. Resistance to lysis was significant in the absence of the RelA protein, implying that resistance could not be explained by activation of the stringent response. Since many environmental stresses promote the expression of HSPs, it is possible that their presence contributes an additional mechanism toward development in bacteria of phenotypic tolerance to beta-lactam antibiotics. (+info)Isolation of Neisseria meningitidis mutants deficient in class 1 (porA) and class 3 (porB) outer membrane proteins. (8/46)
The class 1 major outer membrane protein of Neisseria meningitidis is a serious candidate for a meningococcal vaccine. To facilitate studies on the function of this protein, mutants were isolated that lacked this protein or the structurally related class 3 protein. These mutants were obtained by using the antibody-dependent bactericidal action of the complement system. The class 1 protein-deficient strain grew normally in vitro, whereas growth of the class 3 protein-deficient strain was slightly retarded. The class 3 protein-deficient strain displayed increased resistance to the antibiotics tetracycline and cefsulodin, which is consistent with the proposed role of the protein as a pore-forming protein. The class 1 protein was purified to homogeneity from the class 3 protein-deficient strain. Lipid bilayer experiments revealed that this protein also formed pores. The class 1 protein pores were cation selective. (+info)Cefsulodin is a type of antibiotic known as a cephalosporin, which is used to treat various bacterial infections. It works by interfering with the bacteria's ability to form a cell wall, which is necessary for its survival. By damaging the cell wall, Cefsulodin causes the bacterium to become unstable and eventually die.
Cefsulodin is a broad-spectrum antibiotic, which means it is effective against a wide range of bacteria. It is often used to treat infections caused by Gram-negative bacteria, such as Pseudomonas aeruginosa, which can be difficult to treat with other types of antibiotics.
Cefsulodin is usually given by injection into a vein (intravenously) or muscle (intramuscularly). It may also be given as a topical solution for skin infections. As with all antibiotics, Cefsulodin should only be used under the direction of a healthcare provider, and it is important to take the full course of treatment as prescribed, even if symptoms improve before the medication is finished.
Like other cephalosporins, Cefsulodin can cause side effects such as diarrhea, nausea, vomiting, and rash. In rare cases, it may also cause serious side effects such as an allergic reaction, kidney damage, or seizures. It is important to inform your healthcare provider of any medical conditions you have and any medications you are taking before starting treatment with Cefsulodin.
Cefotiam is a type of antibiotic known as a cephalosporin, which is used to treat various bacterial infections. It works by interfering with the bacteria's ability to form a cell wall, leading to bacterial cell death. Cefotiam has a broad spectrum of activity and is effective against many gram-positive and gram-negative bacteria.
Here is the medical definition of 'Cefotiam':
Cefotiam is a semisynthetic, broad-spectrum, beta-lactam antibiotic belonging to the cephalosporin class. It has activity against both gram-positive and gram-negative bacteria, including many strains that are resistant to other antibiotics. Cefotiam inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), leading to bacterial cell death.
Cefotiam is available in various formulations, including intravenous (IV) and intramuscular (IM) injections, for the treatment of a wide range of infections, such as:
* Lower respiratory tract infections (e.g., pneumonia, bronchitis)
* Urinary tract infections (e.g., pyelonephritis, cystitis)
* Skin and soft tissue infections (e.g., cellulitis, wound infections)
* Bone and joint infections (e.g., osteomyelitis, septic arthritis)
* Intra-abdominal infections (e.g., peritonitis, appendicitis)
* Septicemia (bloodstream infections)
Cefotiam is generally well tolerated, but like other antibiotics, it can cause side effects, including gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea), skin rashes, and allergic reactions. In rare cases, cefotiam may cause serious adverse effects, such as seizures, interstitial nephritis, or hemorrhagicystitis. It should be used with caution in patients with a history of allergy to beta-lactam antibiotics, impaired renal function, or a history of seizure disorders.
It is essential to complete the full course of treatment as prescribed by a healthcare professional, even if symptoms improve, to ensure that the infection is entirely eradicated and to reduce the risk of developing antibiotic resistance.
Cephalosporins are a class of antibiotics that are derived from the fungus Acremonium, originally isolated from seawater and cow dung. They have a similar chemical structure to penicillin and share a common four-membered beta-lactam ring in their molecular structure.
Cephalosporins work by inhibiting the synthesis of bacterial cell walls, which ultimately leads to bacterial death. They are broad-spectrum antibiotics, meaning they are effective against a wide range of bacteria, including both Gram-positive and Gram-negative organisms.
There are several generations of cephalosporins, each with different spectra of activity and pharmacokinetic properties. The first generation cephalosporins have a narrow spectrum of activity and are primarily used to treat infections caused by susceptible Gram-positive bacteria, such as Staphylococcus aureus and Streptococcus pneumoniae.
Second-generation cephalosporins have an expanded spectrum of activity that includes some Gram-negative organisms, such as Escherichia coli and Haemophilus influenzae. Third-generation cephalosporins have even broader spectra of activity and are effective against many resistant Gram-negative bacteria, such as Pseudomonas aeruginosa and Klebsiella pneumoniae.
Fourth-generation cephalosporins have activity against both Gram-positive and Gram-negative organisms, including some that are resistant to other antibiotics. They are often reserved for the treatment of serious infections caused by multidrug-resistant bacteria.
Cephalosporins are generally well tolerated, but like penicillin, they can cause allergic reactions in some individuals. Cross-reactivity between cephalosporins and penicillin is estimated to occur in 5-10% of patients with a history of penicillin allergy. Other potential adverse effects include gastrointestinal symptoms (such as nausea, vomiting, and diarrhea), neurotoxicity, and nephrotoxicity.
I'm sorry for any confusion, but "Sulbenicillin" is not a recognized or established term in medical science or pharmacology. It seems that there might be a spelling mistake or a mix-up with the names of antibiotics. If you meant "Subenicillin," it also doesn't exist in medical literature as a known drug.
If you have any other questions about medical definitions, please provide the correct term, and I will be happy to help.
Azlocillin is a semisynthetic antibiotic belonging to the class of extended-spectrum penicillins. It is derived from the basic penicillin structure and has an additional side chain that provides it with a broader spectrum of activity, including against many Gram-negative bacteria such as Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa.
Azlocillin works by inhibiting the synthesis of bacterial cell walls, which ultimately leads to bacterial death. It is commonly used in the treatment of severe intra-abdominal infections, urinary tract infections, and septicemia caused by susceptible organisms.
Like other antibiotics, azlocillin should be used with caution and only when necessary, as overuse can lead to the development of antibiotic resistance. It is important to note that individual patient responses to medications may vary, and healthcare providers should consider each patient's unique medical history and current health status before prescribing any medication.
Mezlocillin is a type of antibiotic known as a semisynthetic penicillin, which is derived from the Penicillium fungus. It is primarily used to treat infections caused by susceptible Gram-negative bacteria, such as Escherichia coli (E. coli), Klebsiella pneumoniae, and Proteus mirabilis. Mezlocillin works by inhibiting the synthesis of bacterial cell walls, leading to bacterial death.
Mezlocillin is often administered intravenously in a hospital setting due to its poor oral bioavailability. It is typically used in combination with other antibiotics, such as an aminoglycoside, to broaden the spectrum of activity and reduce the risk of bacterial resistance.
Common side effects of mezlocillin include diarrhea, nausea, vomiting, and skin rashes. More serious side effects can include allergic reactions, kidney damage, and hearing loss. Mezlocillin should be used with caution in patients with a history of penicillin allergy or impaired kidney function.
Peptidoglycan glycosyltransferase is not a medical term per se, but rather a biological term used to describe an enzyme that plays a crucial role in the biosynthesis of peptidoglycan, a major component of bacterial cell walls.
In simpler terms, peptidoglycan glycosyltransferase is an enzyme responsible for adding sugar molecules to the growing peptidoglycan structure during bacterial cell wall synthesis. This enzyme catalyzes the transfer of a disaccharide-peptide subunit from a donor molecule (a lipid carrier called undecaprenyl pyrophosphate) to the acceptor molecule (the existing peptidoglycan layer in the cell wall). This process helps maintain the structural integrity and stability of bacterial cells.
Because of its essential role in bacterial cell wall biosynthesis, peptidoglycan glycosyltransferase is considered a potential target for developing new antibiotics to combat bacterial infections.
"Pseudomonas aeruginosa" is a medically important, gram-negative, rod-shaped bacterium that is widely found in the environment, such as in soil, water, and on plants. It's an opportunistic pathogen, meaning it usually doesn't cause infection in healthy individuals but can cause severe and sometimes life-threatening infections in people with weakened immune systems, burns, or chronic lung diseases like cystic fibrosis.
P. aeruginosa is known for its remarkable ability to resist many antibiotics and disinfectants due to its intrinsic resistance mechanisms and the acquisition of additional resistance determinants. It can cause various types of infections, including respiratory tract infections, urinary tract infections, gastrointestinal infections, dermatitis, and severe bloodstream infections known as sepsis.
The bacterium produces a variety of virulence factors that contribute to its pathogenicity, such as exotoxins, proteases, and pigments like pyocyanin and pyoverdine, which aid in iron acquisition and help the organism evade host immune responses. Effective infection control measures, appropriate use of antibiotics, and close monitoring of high-risk patients are crucial for managing P. aeruginosa infections.
Ticarcillin is an antibiotic medication that belongs to the class of drugs called penicillins. It is primarily used to treat infections caused by susceptible bacteria. Ticarcillin has activity against various gram-positive and gram-negative bacteria, including Pseudomonas aeruginosa.
The drug works by inhibiting the synthesis of bacterial cell walls, leading to bacterial death. It is often administered intravenously in a hospital setting due to its poor oral bioavailability. Common side effects include gastrointestinal symptoms such as nausea, vomiting, and diarrhea, as well as allergic reactions, including rash and itching.
It's important to note that the use of ticarcillin should be based on the results of bacterial culture and sensitivity testing to ensure its effectiveness against the specific bacteria causing the infection. Additionally, healthcare providers should monitor renal function during treatment, as ticarcillin can affect kidney function in some patients.
Beta-lactams are a class of antibiotics that include penicillins, cephalosporins, carbapenems, and monobactams. They contain a beta-lactam ring in their chemical structure, which is responsible for their antibacterial activity. The beta-lactam ring inhibits the bacterial enzymes necessary for cell wall synthesis, leading to bacterial death. Beta-lactams are commonly used to treat a wide range of bacterial infections, including respiratory tract infections, skin and soft tissue infections, urinary tract infections, and bone and joint infections. However, some bacteria have developed resistance to beta-lactams through the production of beta-lactamases, enzymes that can break down the beta-lactam ring and render the antibiotic ineffective. To overcome this resistance, beta-lactam antibiotics are often combined with beta-lactamase inhibitors, which protect the beta-lactam ring from degradation.
Beta-lactamases are enzymes produced by certain bacteria that can break down and inactivate beta-lactam antibiotics, such as penicillins, cephalosporins, and carbapenems. This enzymatic activity makes the bacteria resistant to these antibiotics, limiting their effectiveness in treating infections caused by these organisms.
Beta-lactamases work by hydrolyzing the beta-lactam ring, a structural component of these antibiotics that is essential for their antimicrobial activity. By breaking down this ring, the enzyme renders the antibiotic ineffective against the bacterium, allowing it to continue growing and potentially causing harm.
There are different classes of beta-lactamases (e.g., Ambler Class A, B, C, and D), each with distinct characteristics and mechanisms for breaking down various beta-lactam antibiotics. The emergence and spread of bacteria producing these enzymes have contributed to the growing problem of antibiotic resistance, making it increasingly challenging to treat infections caused by these organisms.
To overcome this issue, researchers have developed beta-lactamase inhibitors, which are drugs that can bind to and inhibit the activity of these enzymes, thus restoring the effectiveness of certain beta-lactam antibiotics. Examples of such combinations include amoxicillin/clavulanate (Augmentin) and piperacillin/tazobactam (Zosyn).
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.