Clinical Outcomes of Patients with Methicillin-Resistant Staphylococcus aureus Bacteremia Treated with Vancomycin at an Institution with Suppressed MIC Reporting: Impact of Vancomycin MIC.
Antimicrob Agents Chemother. 2018 Jan 29;:
Authors: Adani S, Bhowmick T, Weinstein MP, Narayanan N
Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of bacteremia and is associated with significant morbidity and mortality. Prior studies evaluating the association of vancomycin MIC and clinical outcomes in patients with MRSA bacteremia have been inconsistent. This study evaluated the association between vancomycin MIC and 30-day in-hospital mortality in patients with MRSA bacteremia. This was a retrospective cohort study of patients with MRSA bacteremia treated with vancomycin for ≥72 hours from January 2013 to August 2016. Vancomycin MICs were determined by broth microdilution via automated susceptibility testing methods. Study groups consisted of patients with MRSA isolates that had vancomycin MIC<2 μg/ml and MIC=2 μg/ml. Covariates included demographics, severity of illness, comorbidities, ICU admission, infectious diseases consultation, infectious sources, and hospital onset of bacteremia. The primary outcome was 30-day in-hospital mortality. Secondary outcomes included duration of bacteremia, persistent bacteremia ≥7 days, recurrence within 30 days, change to alternative antibiotic therapy, and hospital length of stay. Multivariate logistic regression models were analyzed to control for potential confounding variables. There were a total of 166 patients included for analysis, 91patients with vancomycin MIC<2 μg/ml and 75 patients with MIC=2 μg/ml. In the multivariate logistic regression model, a vancomycin MIC=2 μg/ml, compared to MIC<2 μg/ml, was not significantly associated with 30-day in-hospital mortality after adjusting for confounders. Additionally, all secondary outcomes were not statistically significantly different between study groups. In patients with MRSA bacteremia treated with vancomycin, the vancomycin MIC was not associated with differences in clinical outcomes.
PMID: 29378704 [PubMed - as supplied by publisher]