Comparison of four chromogenic media for culture-based screening of meticillin-resistant Staphylococcus aureus

Abstract

Meticillin-resistant Staphylococcus aureus (MRSA) are responsible for nosocomial and community-acquired infections. Detection of MRSA is of utmost importance for the adaptation of infection control and therapeutic strategies. To date, selective agar plates constitute the standard routine method for reliable detection of this worldwide infectious problem. The performance of four different chromogenic media was evaluated in this study for MRSA detection and identification on >240 consecutive swab samples. The results indicate that primary plating on MRSASelect or MRSA ID is more sensitive than screening with oxacillin-based culture media. In addition, the utilization of cefoxitin- or cephamycin-containing plates reduces significantly the number of required confirmatory tests. Several selective agar plates allowing the identification of S. aureus are commercially available. However, their respective performances under real conditions of utilization are heterogeneous, underlining the absence of a gold standard medium for MRSA screening.