Contribution of beta-lactamases to beta-lactam susceptibilities of susceptible and multidrug-resistant Mycobacterium tuberculosis clinical isolates.
The beta-lactamases in 154 clinical Mycobacterium tuberculosis strains were studied. Susceptibilities to beta-lactam antibiotics, their combination with clavulanate (2:1), and two fluoroquinolones were determined in 24 M. tuberculosis strains susceptible to antimycobacterial drugs and in nine multiresistant strains. All 154 M. tuberculosis isolates showed a single chromosomal beta-lactamase pattern (pI 4.9 and 5.1). M. tuberculosis beta-lactamase hydrolyzes cefotaxime with a maximum rate of 22.5 +/- 2.19 IU/liter (strain 1382). Neither amoxicillin, carbenicillin, cefotaxime, ceftriaxone, nor aztreonam was active alone. Except for aztreonam, beta-lactam combinations with clavulanate produced better antimycobacterial activity.
Segura
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Laboratori de Referència de Catalunya, Universitat Autònoma de Barcelona, Spain. msalvador@lrc.es
Salvadó
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Collado
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Chaves
J
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Coira
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A
D019818:Clavulanic Acid / Q000494:pharmacology*; D018432:Drug Resistance, Multiple / Q000235:genetics*; D004359:Drug Therapy, Combination / Q000494:pharmacology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism
D019818:Clavulanic Acid; D001618:beta-Lactamases