β-lactams enhance vancomycin activity against methicillin-resistant Staphylococcus aureus bacteremia compared to vancomcyin alone.
Antimicrob Agents Chemother. 2013 Oct 21;
Authors: Dilworth TJ, Ibrahim O, Hall P, Sliwinski J, Walraven C, Mercier RC
Abstract
Background: Vancomycin (VAN) is often used to treat methicillin-resistant Staphylococcus aureus (MRSA) bacteremia despite a high incidence of microbiological failure. Recent in vitro analyses of β-lactams in combination with VAN demonstrated synergistic activity against MRSA. The goal of this study was to examine the impact of combination therapy with VAN and a β-lactam (COMBO) on the microbiological eradication of MRSA bacteremia compared to VAN alone.Methods: This was a retrospective cohort study of patients with MRSA bacteremia who received COMBO therapy or VAN alone. Microbiological eradication of MRSA, defined as a negative blood culture obtained after initiation of therapy, was used to evaluate the efficacy of each regimen.Results: A total of 80 patients were included: 50 patients in the COMBO group and 30 patients in the VAN alone group. Microbiological eradication was achieved in 48 patients (96%) in the COMBO group compared to 24 patients (80%) in the VAN alone group (p=0.021). In a multivariable model, the treatment with COMBO had a higher likelihood of achieving microbiological eradication (adjusted odds ratio 11.24, 95% CI [1.7 - 144.3]; p=0.01). In patients with infective endocarditis (n=22), 11/11 (100%) who received COMBO therapy achieved microbiological eradication compared to 9/11 (81.8%) treated with VAN alone but the difference was not statistically significant (p=0.20).Conclusions: Patients with MRSA bacteremia who received COMBO therapy were more likely to experience microbiological eradication of MRSA than patients who received VAN alone.
PMID: 24145519 [PubMed - as supplied by publisher]