Hospitals strive to reduce methicillin-resistantStaphylococcus aureus(MRSA) prevalence via active surveillance of inpatient populations. Rapid and inexpensive screening methods are utilized when molecular methods are not operationally feasible. In this multisite clinical trial, the utility of Bio-Rad's MRSASelectII was evaluated for MRSA identification from remnant nares and wound swabs. The prevalence of MRSA was 11.1% (n= 1,384) from nares samples and 18.1% (n= 842) from wound samples. MRSASelectII had an overall concordance of 95.4% (confidence interval [CI] = 94.5% to 96.2%) compared to a broth-enriched reference standard. Comparisons between results, stratified by examination times, exhibited a nonsignificant trend toward increased positivity at prolonged incubation times. Cefoxitin screening of colonies directly from MRSASelectII was 96.7% (95.8% to 97.3%) concordant compared to testing of colonies following broth enrichment. A comparison of MRSASelectand MRSASelectII revealed no statistical differences; however, the latter exhibited earlier positivity, greater selectivity, and more intense indicator staining, which resulted in facilitated differentiation of positive results. MRSASelectII agar is a simple, rapid, and robust method to routinely screen patients for MRSA colonization without the need for additional testing.
Spectra MRSA, a New Chromogenic Agar Medium To Screen for Methicillin-Resistant Staphylococcus aureus
