Variable susceptibility to piperacillin/tazobactam amongst Klebsiella spp. with extended-spectrum beta-lactamases
| Autor: | Meifang Yuan, Gioia S. Babini, David M. Livermore, Lucinda M. C. Hall |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
Microbiology (medical)
Klebsiella medicine.drug_class Antibiotics Penicillanic Acid Microbial Sensitivity Tests Drug resistance Tazobactam beta-Lactamases Microbiology Drug Resistance Multiple Bacterial polycyclic compounds medicine Humans Pharmacology (medical) Antibacterial agent Piperacillin Pharmacology biology biochemical phenomena metabolism and nutrition bacterial infections and mycoses biology.organism_classification Enterobacteriaceae Piperacillin Tazobactam Drug Combination Infectious Diseases Piperacillin/tazobactam bacteria Bacterial Outer Membrane Proteins medicine.drug |
| Zdroj: | Journal of Antimicrobial Chemotherapy. 51:605-612 |
| ISSN: | 1460-2091 |
| DOI: | 10.1093/jac/dkg114 |
| Popis: | MICs of piperacillin/tazobactam are conventionally determined by varying the concentration of piperacillin in the presence of a fixed 4 mg/L tazobactam. When tested in this way, the MIC distribution for Klebsiella isolates with extended-spectrum beta-lactamases (ESBLs) is strongly bimodal, such that many producers are inhibited at 16 + 4 mg/L whilst others require MICs of > or =512 + 4 mg/L. When, however, piperacillin/tazobactam was tested as a fixed 8:1 ratio, the MIC distribution became unimodal. If clavulanate 4 mg/L was combined with piperacillin, a unimodal MIC distribution was seen for ESBL-producing Klebsiella spp. but a bimodal distribution arose if the clavulanate concentration was reduced to 0.25 mg/L. These data for alternative combinations suggested that the bimodal MIC distribution seen for piperacillin + tazobactam 4 mg/L was a titration effect, not a reflection of some ESBLs being resistant to tazobactam. Even within single strains, as defined by serotype and DNA fingerprints, there was considerable variation in susceptibility to piperacillin + tazobactam 4 mg/L, with some representatives highly susceptible and others highly resistant. Some of the more resistant representatives produced more of their ESBL, or had a greater number of beta-lactamase types, but these associations were not universal. Elevated resistance to piperacillin + tazobactam was not associated with porin change in any ESBL producer examined, but has been found by others. |
| Databáze: | OpenAIRE |
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