Prevalence and invasiveness of community-acquired methicillin-resistant Staphylococcus aureus: A meta-analysis.

Background: Reports suggest that the prevalence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has increased, and that CA-MRSA is more virulent than healthcare-associated (HA)-MRSA. Aims: The aim of this study is to gain a better understanding of the invasiveness and prevalence of CA-MRSA in patients; we systematically reviewed the literature by conducting a meta-analysis. Materials and Methods: We searched the MEDLINE and PUBMED databases from the year these databases were established to January 2013. Results: The pooled CA-MRSA prevalence among 50,737 patients from 33 studies was 39.0% (range, 30.8-47.8%). The pooled CA-MRSA prevalence rates among pediatric and adult patients with MRSA infection were 50.2% (range, 37.5-62.8%) and 42.3% (range, 16.4-73.3%), respectively. The pooled CA-MRSA prevalence rates of MRSA-infected patients in Asia, Europe, and North America were 23.1% (range, 12.0-39.8%), 37.4% (range, 21.1-56.4%), and 47.4% (range, 35.8-59.4%), respectively. Using the random effects model, we determined that the pooled odds ratio of invasive infections in CA- and HA-MRSA was 0.30 (95% confidence interval: 0.08-1.10; P = 0.07, test for heterogeneity P < 0.00001). Conclusions: The prevalence of CA-MRSA in MRSA infection varied with area and population. No difference in the ability to cause invasive infections was found between CA- and HA-MRSA. This finding challenges the view that CA-MRSA is more virulent than HA-MRSA.