Vancomycin associated with higher mortality in MRSA bloodstream infections

van Hal SJ. Clin Infect Dis. 2012;doi:10.1093/cid/cir935.

New findings published in Clinical Infectious Diseases indicate that increased vancomycin minimum inhibitory concentration was associated with a higher mortality rate in patients with methicillin-resistant Staphylococcus aureus bloodstream infections.

“Thus, institutions should consider conducting Etest minimum inhibitory concentration (MIC) on all methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infections isolates,” Sebastiaan J. van Hal, FRACP, FRCPA, of the University of Western Sydney, Australia, and colleagues wrote in the study.

The study included a systemic review of 22 studies that included treatment outcomes or mortality associated with vancomycin MIC conducted between January 1996 and August 2011.

Vancomycin MIC was significantly associated with mortality for MRSA infection (OR=1.64; 95% CI, 1.14-2.37). This association was higher in patients with MRSA bloodstream infections (OR=1.58; 95% CI, 1.06-2.37) and isolates with a vancomycin MIC of at least 2 mcg/mL by Etest (OR=1.72; 95% CI, 1.34-2.21).

In addition, isolates with a vancomycin MIC of at least 1.5 mcg/mL were significantly associated with treatment failure (OR=2.69; 95% CI, 1.60-4.51).

“Although these data highlight concerns about vancomycin, currently, there are no data to support better survival rates with alternative antibiotics,” the researchers wrote. “Data are needed to determine whether other agents can remedy these outcomes observed with vancomycin for MRSA infections with elevated vancomycin MIC values.”

Disclosure: Dr. van Hal reports receiving grant support from Gilead, Merck, Novartis and Pfizer.

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