beta-lactamase

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Related to Beta-lactamases: Carbapenem

β-lac·ta·mase

(lak'tă-mās),
An enzyme produced by many species of bacteria that disrupts the four-membered β-lactam ring of penicillin and cephalosporin groups of antibiotics, destroying their antimicrobial activity. The ability of an organism to produce a β-lactamase may be chromosomal and constitutive or a plasmid-associated acquired property.

β-lactamase

/β-lac·ta·mase/ (lak´tah-mās) any of a group of enzymes, produced by almost all gram-negative bacteria, that hydrolyze the β-lactam ring of penicillins and cephalosporins, destroying their antibiotic activity. Individual enzymes may be called penicillinases or cephalosporinases based on their specificities.

beta-lactamase

(bā′tə-lăk′tə-mās′, -māz′, bē′-)
n.
Any of various enzymes that hydrolyze and inactivate beta-lactam antibiotics such as penicillin, found in many antibiotic-resistant bacteria.

beta-lactamase

[-lak′təmāz]
Etymology: lactam, a cyclic amide, ase, enzyme
a bacterial enzyme that catalyzes the hydrolysis of the beta-lactam ring of some penicillins and cephalosporins, producing penicilloic acid and rendering the antibiotic ineffective. Also called cephalosporinase, penicillinase.

be·ta-lac·ta·mase

(bā'tă lak'tā-mās)
An enzyme produced by many species of bacteria that disrupts the four-membered β-lactam ring of penicillin and cephalosporin groups of antibiotics, destroying their antimicrobial activity.
Synonym(s): penicillinase.

β-lactamase

either of two enzymes: β-lactamase I is penicillinase; β-lactamase II is cephalosporinase.
References in periodicals archive ?
Molecular characterization of extended-spectrum beta-lactamase producing Enterobacteriaceae in a Saudi Arabian tertiary hospital.
The isolates resistant to ceftazidime, cefotaxime and cefoxitin were screened positive for AmpC beta-lactamases and further confirmed by inhibitor based method using boronic acid disc.
Extended-spectrum beta-lactamases in Klebsiella pneumoniae bloodstream isolates from seven countries: dominance and widespread prevalence of SHV- and CTX-M-type beta-lactamases.
9 MBLs have not only become a source of increased morbidity and mortality but also represent a clinical threat due to their unrivalled spectrum of activity and their resistance to therapeutic serine beta-lactamase inhibitors.
Antibiotic resistance rates of extended spectrum beta-lactamase producing Escherichia coli and Klebsiella spp.
Transcontinental importation into the UK of Escherichia coli expressing a plasmid-mediated AmpC-type betalactamase exposed during an outbreak of SHV-5 extended-spectrum beta-lactamase in a Leeds hospital.
This beta-lactamase inhibitor has the potential for an expanded spectrum against multi-drug resistant bacteria and could be a much needed option for patients suffering from difficult-to-treat infections.
Prevalence of plasmid-mediated AmpC beta-lactamases in a Chinese university hospital from 2003 to 2005: First report of CMY-2-Type AmpC beta-lactamase resistance in China.
Resistance to carbapenem is often mediated by production of MBL, a class B-type beta-lactamases that requires bivalent metal ion, usually Zn for their activity.
About one-tenth of isolates of gram-negative pathogens seem to produce extended-spectrum beta-lactamases (ESBL) (18).
Among the topics are recent trends in resistance to cell envelope-active antibacterial agents among key bacterial pathogens, viable screening targets related to the bacterial cell wall, the proliferation and significance of clinically relevant beta-lactamases, metallo-beta-lactamase structure and function, siderophore conjugates, and the role of the cell membrane and cell wall in mechanisms of daptomycin resistance in Staphylococcus aureus.

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