Comparison of Vancomycin Treatment Failures for Methicillin-ResistantStaphylococcus aureus Bacteremia Stratified by MinimumInhibitory Concentration

摘要

Optimal treatment of methicillin-resistant bacteremias (MRSABs) with vancomycinminimum inhibitory concentrations (MICs) high within the susceptible range is ofconcern due to the high rate of mortality and increased prevalence. The purpose of this study is to evaluate vancomycintreatment failures in patients with MRSAB stratified by vancomycin MIC. In this retrospective chart review, patients ≥19 yearsof age with MRSAB between July 2010 and December 2016 were included if theyreceived intravenous vancomycin for ≥72 hours. Vancomycin treatment failureswere compared between patients with vancomycin MICs of ≤1 mg/L and 2 mg/L.Vancomycin treatment failure was defined as microbiological failure at 7 days.Inpatient mortality, 30-day readmission, vancomycin-associated nephrotoxicity,and early bacteremia clearance at 48 to 96 hours were assessed as secondaryendpoints. Fifty-eight patients were included in thevancomycin MIC ≤1 mg/L group and 22 patients in the vancomycin MIC 2 mg/L group.No significant difference was found in vancomycin treatment failures at 7 daysbetween groups (88% vs 91%, respectively; = .850). At 96hours, there was no significant difference in vancomycin treatment failuresbetween groups (72% vs 90%, respectively; = .127). Nosignificant difference was found in mortality ( > .99) or30-day readmission ( > .99). Inthis study, vancomycin treatment failures were not more prevalent in patientswith vancomycin MIC of 2 mg/L at 7 days. Regardless of MIC, antibiotics shouldbe switched to an alternative agent at 7 days for persistent bacteremia.