Estimated mortality with early empirical antibiotic coverage of methicillin-resistant Staphylococcus aureus in hospitalized patients with bacterial infections: a systematic review and meta-analysis.

OBJECTIVES: We performed a systematic review and meta-analysis to estimate the effect of early active empirical antibiotics for MRSA on mortality, both in patients admitted with MRSA infections and in patients admitted with common infectious syndromes, for whom the causative pathogen may not have been MRSA.

METHODS: A systematic literature search was conducted using Embase, MEDLINE, PubMed, Web of Science, Cochrane, Scopus and Google Scholar from the earliest entry through to 26 April 2022. We included studies of patients hospitalized with culture-proven MRSA infections that compared mortality rates depending on whether patients received active empirical antibiotics. The primary outcome was the adjusted OR for mortality with early active empirical antibiotics. After performing random-effects meta-analysis, we estimated the absolute risk reduction in mortality with initial empirical MRSA coverage for common infectious syndromes based on the prevalence of MRSA and baseline mortality rate for each syndrome, as reported in the medical literature.

RESULTS: Of an initial 2136 unique manuscripts, 37 studies (11 661 participants) met our inclusion criteria. Fifteen studies (6066 participants) reported adjusted OR of mortality. The pooled adjusted OR for mortality was 0.64 (95% CI, 0.48-0.84), favouring active empirical antibiotics. The estimated absolute mortality benefit was 0% for patients with pneumonia, 0.1% (95% CI, 0.04-0.2) for non-critically ill patients with soft tissue infections, 0.04% (95% CI, 0.01-0.05) for non-critically ill patients with urinary tract infections, 0.6% (95% CI, 0.2-1.0) for patients with septic shock, and 1.0% (95% CI, 0.3-1.4) for patients with catheter-related infections admitted to ICUs.

CONCLUSIONS: For the three most common infections in the hospital, the absolute benefit on mortality of empirical antibiotics against MRSA is 0.1% or less. Meaningful benefit of empirical antimicrobials against MRSA is limited to patients with approximately 30% mortality and 10% prevalence of MRSA. Avoiding empirical antibiotics against MRSA for low-risk infections would substantially reduce the use of anti-MRSA therapy.