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an enzyme produced by certain bacteria that inactivates penicillin, so that such bacteria have increased resistance to the antibiotic; a purified form from Bacillus cereus is used in treatment of reactions to penicillin.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
1. Synonym(s): β-lactamase
2. A purified enzyme preparation obtained from cultures of a strain of Bacillus cereus; formerly used to treat slowly developing or delayed penicillin reactions.
Farlex Partner Medical Dictionary © Farlex 2012
Any of several beta-lactamase enzymes that cleave the beta-lactam ring in penicillins. Penicillinases are found in many penicillin-resistant bacteria.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
penicillinaseAn enzyme present in some bacteria, especially STAPHYLOCOCCI, that inactivates penicillins, by HYDROLYSIS of the beta-lactam bond, so that the organisms possess resistance to the drug. Also known as beta-lactamase.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
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.
Medical Dictionary for the Dental Professions © Farlex 2012