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Beta-lactam/daptomycin fails to reduce mortality in MSSA

The combination of beta-lactam plus daptomycin did not improve mortality rates in patients with methicillin-susceptible Staphylococcus aureus, or MSSR, bacteremia, compared with beta-lactam alone, according to data published in Clinical Infectious Diseases.

“Mortality rates from Staphylococcus aureus bacteremia are high and have only modestly improved in recent decades,” Sara Grillo, from the department of infectious disease at Bellvitge University Hospital and the Institut d’Investigacio Biomedica de Bellvitge in Barcelona, and colleagues wrote.

“Given the high mortality rates from S. aureus bacteremia, there is increasing interest in finding other antibiotic strategies to improve clinical outcomes,” they added.

Grillo and colleagues conducted a retrospective cohort study to determine the efficacy of beta-lactam and daptomycin combination for treating MSSA bacteremia compared with beta-lactam alone.

The researchers enrolled 350 patients presenting to a tertiary hospital with MSSA bacteremia between January 2011 and December 2017. Of those, 136 received beta-lactam and daptomycin combination and 214 received beta-lactam monotherapy. Participants were propensity score matched one-to-two.

Pitt scores were used to determine the severity of the bacteremia. Mortality rates at days 7, 30 and 90 were recorded.

Data showed that patients receiving the combination of beta-lactam and daptomycin were more likely to have higher Pitt scores and persistent bacteremia than those receiving beta-lactam monotherapy. All-cause mortality rates at 7 (8.18% vs. 7.74%), 30 (17.3% vs. 16.1%) and 90 days (22.7% vs. 23.2%) did not significantly differ between the two groups.

“Beta-lactam and daptomycin combination failed to reduce mortality rates in patients with MSSA bacteremia,” Grillo and colleagues concluded. “Treatment strategies to improve survival in MSSA bacteremia are urgently needed. Randomized controlled trials testing different combination therapies are warranted.” – by Alaina Tedesco

Disclosures: The authors report no relevant financial disclosures.