title: beta-Lactamase activity in mycobacteria including Mycobacterium avium and suppression of their growth by a beta-lactamase-stable antibiotic.
abstract: beta-Lactamase has been reported from only a few mycobacteria. It is widely assumed that Mycobacterium avium strains do not contain the enzyme, but earlier assays were done using insensitive methods. Thus the beta-lactamase activity in cell-free extracts of ten selected strains of mycobacteria, including four strains of M. avium, was determined using a highly sensitive spectrophotometric method. The results showed that all the mycobacteria tested possess the enzyme, which explains their resistance to beta-lactam antibiotics. However, some of the bacteria differed from others in the action of the inhibitors, clavulanate, sulbactam and tazobactam against their beta-lactamases. Growth of the mycobacteria was suppressed by novel combinations of the beta-lactam/beta-lactamase-inhibitors, and by a new beta-lactamase-stable cephalosporin, Cefepime (aminothiazolyl methoxyimino cephalosporin). The results presented, as well as reports of previous studies in vivo, suggest that the intracellular growth of the bacilli or the high partition coefficient of a beta-lactamase inhibitor such as sulbactam does not impede the antimycobacterial action of these compounds.
authors.affiliation: Laboratory Research Branch, GWL HD Center at Louisiana State University, Baton Rouge 70894-5072, U.S.A.
authors.forename: K
authors.initials: K
authors.lastname: Prabhakaran
authors.forename: E B
authors.initials: EB
authors.lastname: Harris
authors.forename: B
authors.initials: B
authors.lastname: Randhawa
authors.forename: R C
authors.initials: RC
authors.lastname: Hastings
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000077723:Cefepime; D002455:Cell Division / Q000187:drug effects; D002511:Cephalosporins / Q000494:pharmacology*; D019818:Clavulanic Acid; D002969:Clavulanic Acids / Q000494:pharmacology; D004352:Drug Resistance, Microbial; D007538:Isoniazid / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D009161:Mycobacterium / Q000187:drug effects* / Q000201:enzymology* / Q000254:growth & development; D009162:Mycobacterium avium / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development; D010397:Penicillanic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D013307:Streptomycin / Q000494:pharmacology; D013407:Sulbactam / Q000494:pharmacology; D000078142:Tazobactam; D065093:beta-Lactamase Inhibitors; D001618:beta-Lactamases / Q000032:analysis*
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D002969:Clavulanic Acids; D065093:beta-Lactamase Inhibitors; D019818:Clavulanic Acid; D000077723:Cefepime; D010397:Penicillanic Acid; D001618:beta-Lactamases; D013407:Sulbactam; D000078142:Tazobactam; D007538:Isoniazid; D013307:Streptomycin