beta-lactamase

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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.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
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While this assay is not currently commercially available, Check-Points (Wageningen, Gelderland, Netherlands) produces several commercially microarray kits to detect cephalosporinases, ESBLs, and carbapenemases.
Figure 2: Cephalosporinase/penicillinase induced neutralization of 13 [beta]-lactam antibiotics which inhibit growth of Kocuria rhizophila ATCC 9341 on TSA contact plates Reference without With cephalosporinase cephalosporinase and penicillinase or penicillinase (medium contains (medium contains lecithin end Tween 80) lecithin.
Extension of resistance to cefepime and cefpirome associated to a six amino acid deletion in the H-10 helix of the cephalosporinase of an Enterobacter cloacae clinical isolate.
enterocolitica isolates harbored chromosomal genes bl[a.sub.A] and bl[a.sub.B] encoding for two beta-lactamases, respectively, BlaA (a non-inducible broad-spectrum carbenicillinase) and BlaB (an AmpC-type inducible cephalosporinase).
Moreover, they possess inducible, chromosomally encoded AmpC cephalosporinase belonging to Ambler class C enzymes [7].
coli, and increased prevalence of other mechanisms (e.g., chromosomal AmpC cephalosporinase induction/derepression or porin modification) as the basis in Enterobacter species.
These antibiotics are not readily affected by cephalosporinase or penicillinase enzymes produced by certain bacteria [5].
The susceptibility pattern with regard to cefepime probably reflects excellent activity against chromosomal-located cephalosporinase (Amp-C)-producing isolates.
anthracis isolates of a cephalosporinase, an enzyme that inhibits the antibacterial activity of cephalosporins such as ceftriaxone.
These isolates could be IRT or OXA enzymes or cephalosporinase hyperproduction.