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Beta-lactam resistance in Nocardia brasiliensis is mediated by beta-lactamase and reversed in the presence of clavulanic acid.
Wallace, R J; Nash, D R; Johnson, W K; Steele, L C; Steingrube, V A.
Affiliation
  • Wallace RJ; Department of Microbiology, University of Texas Health Center at Tyler 75710.
J Infect Dis ; 156(6): 959-66, 1987 Dec.
Article in En | MEDLINE | ID: mdl-3500241
Forty clinical isolates and the type strain of Nocardia brasiliensis were screened for susceptibility to 20 beta-lactams. Isolates exhibited a single pattern of resistance, with large zones of inhibition by disk diffusion and low MICs by broth and agar dilutions only to cefotaxime, ceftriaxone, ceftizoxime, Augmentin, and Timentin. All strains produced beta-lactamase, with five different enzyme patterns by isoelectric focusing. Despite the differences in their isoelectric points, the enzymes had the same substrate profiles, with equivalent activity against penicillin, ampicillin, cefamandole, cephalothin, and cephalordine. In an in vitro assay, the enzymes were highly susceptible to clavulanic acid. The MIC50 and MIC90 for the combination of amoxicillin and clavulanic acid (Augmentin) was 2 and 4 micrograms/ml, respectively, compared with 16 micrograms/ml for both values for amoxicillin alone. These studies suggest that beta-lactamase is the major mechanism of beta-lactam resistance in this species and that Augmentin is the first oral beta-lactam with good potential for treating infections due to N. brasiliensis.
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Collection: 01-internacional Database: MEDLINE Main subject: Beta-Lactamases / Anti-Bacterial Agents / Nocardia Limits: Humans Country/Region as subject: America do sul / Brasil Language: En Journal: J Infect Dis Year: 1987 Document type: Article Country of publication: United States
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Collection: 01-internacional Database: MEDLINE Main subject: Beta-Lactamases / Anti-Bacterial Agents / Nocardia Limits: Humans Country/Region as subject: America do sul / Brasil Language: En Journal: J Infect Dis Year: 1987 Document type: Article Country of publication: United States