beta-lactamase

(redirected from cephalosporinase)
Also found in: Dictionary, Thesaurus, Medical.
Related to cephalosporinase: penicillinase

beta-lactamase

[¦bād·ə ′lak·tə‚mās]
(microbiology)
A bacterial enzyme that catalyzes the hydrolysis of the lactam ring in some penicillin antibiotics, rendering them ineffective.
Mentioned in ?
References in periodicals archive ?
ampC cephalosporinase of Escherichia coli K-12 has a different evolutionary origin from that of beta-lactamases of the penicillinase type.
Several class A, B, and D [beta]-lactamases (2,8) as well as chromosome-mediated cephalosporinases (12) confer various resistance phenotypes.
asburiae naturally produces a cephalosporinase but no carbapenemase and may be responsible for nosocomial infections (23).
Both GS553 and GS554 strains, which produced cephalosporinase as well as penicillinase, were resistant to cefotetan, cefmetazole, and cefoxitin as well as piperacillin, cefotaxime, ceftriax-one, cefpodoxime, cefepime, and aztreonam.
Characterization of a novel plasmid-mediated cephalosporinase (CMY-9) and its genetic environment in an Escherichia coli clinical isolate.
Heterogeneity of AmpC cephalosporinases of Hafnia alvei clinical isolates expressing inducible or constitutive ceftazidime resistant phenotypes.
This resistance is caused by production of various class A extended-spectrum a-lactamases (ESBLs) and class C cephalosporinases in Salmonella enterica (1).
These [beta]-lactamases are derivatives of the chromosomally encoded clavulanate-resistant AmpC cephalosporinases of bacteria such as Enterobacter spp.
Occasionally, cephamycin-resistant strains produce plasmid-mediated [beta]-lactamases such as CMY-2, which are derived from bacteria with chromosomally encoded AmpC cephalosporinases (3).
coli AmpC hyperproducers or isolates that produce plasmid-mediated cephalosporinases are technically demanding for clinical laboratories.
These included enzymes that originated from the chromosomally encoded AmpC cephalosporinases of bacteria.