Influence of β-lactamase inhibitors on the activity of oxacillin against methicillin-resistant Staphylococcus aureus
- 28 February 1995
- journal article
- Published by Elsevier BV in Diagnostic Microbiology and Infectious Disease
- Vol. 21 (2), 81-84
- https://doi.org/10.1016/0732-8893(95)00026-7
Abstract
We studied the in vitro susceptibility to oxacillin of 46 isolates of methicillin-resistant Staphylococcus aureus (MRSA) isolates with a minimum inhibitory concentration (MIC) >8 μg/ml of oxacillin, with and without adding clavulanic acid, sulbactam, or tazobactam in three different concentrations (2, 4, and 8 μg/ml). All 46 strains were found by the rapid chromogenic cephalosporin method to be β-lactamase producers. For those strains with low-level resistance (MIC of 16 or 32 μg/ml), the MICs of oxacillin decreased four- to 32-fold and two- to 32-fold after adding sulbactam and tazobactam, respectively. For those with high-level resistance (MIC of ⩾64 μg/ml), the MICs either did not change or decreased only two-fold after we added one of three β-lactamase inhibitors. The results suggest that β-lactamase production probably plays a role in resistance to oxacillin in those MRSA strains of low-level oxacillin resistance.Keywords
This publication has 13 references indexed in Scilit:
- Comparison of conventional susceptibility tests with direct detection of penicillin-binding protein 2a in borderline oxacillin-resistant strains of Staphylococcus aureusAntimicrobial Agents and Chemotherapy, 1991
- Borderline susceptibility to antistaphylococcal penicillins is not conferred exclusively by the hyperproduction of beta-lactamaseAntimicrobial Agents and Chemotherapy, 1991
- Further characterization of borderline methicillin-resistant Staphylococcus aureus and analysis of penicillin-binding proteinsAntimicrobial Agents and Chemotherapy, 1990
- Methicillin-Resistant Staphylococcus aureusInfectious Disease Clinics of North America, 1989
- Antibiotic resistance in Australia with special reference to sulbactam/ampicillinDiagnostic Microbiology and Infectious Disease, 1989
- Low-level methicillin resistance in strains of Staphylococcus aureusAntimicrobial Agents and Chemotherapy, 1989
- Implications of Acquired Oxacillin Resistance in the Management and Control of Staphylococcus aureus InfectionsThe Journal of Infectious Diseases, 1988
- Methicillin-resistant staphylococciClinical Microbiology Reviews, 1988
- Variation in the potentiation of β-lactam antibiotic activity by clavulanic acid and sulbactam against multiply antibiotic-resistant bacteriaJournal of Antimicrobial Chemotherapy, 1986
- Novel Method for Detection of β-Lactamases by Using a Chromogenic Cephalosporin SubstrateAntimicrobial Agents and Chemotherapy, 1972