Community‐Acquired Methicillin‐Resistant<i>Staphylococcus aureus:</i>A Meta‐Analysis of Prevalence and Risk Factors

TLDR

Carriage of MRSA among individuals without health‑care risk factors has increased. The authors conducted a meta‑analysis of studies reporting CA‑MRSA prevalence in hospitalized patients and MRSA colonization rates in community members. The analysis revealed that CA‑MRSA constitutes about 30–37% of hospital MRSA isolates, that 85% of CA‑MRSA patients have at least one health‑care risk, and that community colonization is low (≈1.3% overall and ≤0.24% among those without health‑care exposure), highlighting the importance of controlling nosocomial MRSA to curb community spread.

Abstract

Reports suggest that carriage of methicillin-resistant Staphylococcus aureus (MRSA) among persons without health care-associated risks has increased. A meta-analysis of studies reporting the prevalence of community-acquired MRSA (CA-MRSA) among MRSA isolates from hospitalized patients or the prevalence of MRSA colonization among community members was conducted. The CA-MRSA prevalence among hospital MRSA was 30.2% in 27 retrospective studies and 37.3% in 5 prospective studies; 85% of all patients with CA-MRSA had > or =1 health care-associated risk. The pooled MRSA colonization rate among community members was 1.3% (95% confidence interval [CI], 1.04%-1.53%), but there was significant heterogeneity among study populations. Community members from whom samples were obtained in health care facilities were more likely to be carrying MRSA than were community members from whom samples were obtained outside of the health care setting (relative risk, 2.35; 95% CI, 1.56-3.53). Among studies that excluded persons with health care contacts, the MRSA prevalence was 0.2%. Moreover, most persons with CA-MRSA had > or =1 health care-associated risk, which suggests that the prevalence of MRSA among persons without risks remains low (< or =0.24%). Effective control of dissemination of MRSA throughout the community likely will require effective control of nosocomial MRSA transmission.