A cost-effective protocol for screening patients for methicillin-resistant Staphylococcus aureus

The incidence of hospital-acquired infection with methicillin-resistant Staphylococcus aureus (MRSA) is rising worldwide. Rapid identification of MRSA carriers is an important step in reducing the risk of transmission to other patients. Molecular methods are increasingly popular but are technically demanding and expensive. This study assesses the modification of one of the commercially available latex agglutination tests (Mastalex-MRSA) for the identification of penicillin-binding protein 2' on known strains of MRSA as well as other organisms identified from chromogenic agar plates. A total of 3050 patients with unknown MRSA status were processed through the routine laboratory during the investigation period and 73 of these were presumptive positive following overnight incubation. Of 70 patients who could be evaluated, 32 (43.8%) specimens would be suitable for use with the kit directly from overnight incubation on chromogenic agar, and the other 38 (52.1%) would be suitable following four hours' incubation on blood agar. The cost of one positive MRSA test with the inclusion of this test is Euro 15.15 compared with published reports of Euro 35.00 for a commercial polymerase chain reaction (PCR) test. This protocol would allow the reporting of presumptive positive MRSA results approximately 24 hours earlier than currently achieved.