Systematic review and meta-analysis of vancomycin therapeutic level for treatment of vancomycin-sensitive enterococcal infections

AIMS: Evidence on the optimal targets of vancomycin for treating other Gram-positive infections apart from methicillin-resistant Staphylococcus aureus (MRSA) is lacking. This review aims to identify the recommended vancomycin therapeutic level for favourable clinical outcomes among patients infected with vancomycin-sensitive enterococcal infections.

METHODS: Analytical studies describing the vancomycin levels of vancomycin-sensitive enterococcal infections among adult population were searched. The primary outcome was 30-day all-cause mortality, and the secondary outcomes were clinical failure and nephrotoxicity. Study characteristics were extracted and pooled using random-effects meta-analysis. The study quality was assessed using the Joanna Briggs Institute critical appraisal tool.

RESULTS: A total of nine retrospective cohorts studies involving 1013 patients with vancomycin-sensitive enterococci were included. The meta-analysis found that high area under the curve to minimum inhibitory concentration ratio (AUC/MIC) of vancomycin ≥ 389 mg*h/L significantly lowered the 30-day mortality (odds ratio [OR], 0.44, 95% confidence interval [CI], 0.26-0.75). Analysis of the target AUC/MIC showed that high vancomycin AUC/MIC (≥ 389-400 mg*h/L) significantly reduced clinical failure rate (OR 0.59, 95% CI 0.37-0.94). The mortality and treatment failure rates did not differ significantly between those with high or low trough levels. Higher vancomycin AUC/MIC and trough levels were significantly associated with increased nephrotoxicity (OR 3.11, 95% CI 1.65-5.89; OR 2.95, 95% CI 1.60-5.44, respectively).

CONCLUSIONS: The use of a higher vancomycin AUC/MIC concentration can be effective to reduce 30-day mortality and clinical failure but this needs to take into consideration the risk of nephrotoxicity. Well-conducted prospective studies are warranted due to the scarcity of evidence.