Evaluation of CHROMagar Staph aureus, a New Chromogenic Medium, for the Detection of Nosocomial Methicillin-Resistant Staphylococcus aureus / 감염

ABSTRACT

BACKGROUND: Staphylococcus aureus remains one of the most frequently encountered bacterial pathogens and is responsible for a variety of mild to life- threatening infections. There is a substantial body of evidence that individuals who are asymptomatic nasal carriers of S. aureus are at increased risk of developing serious staphylococcal infections. Approximately 20% to 30% of health care workers at any given time are also nasal carriers of S. aureus. A subset of these may spread the organism to patients by direct contact transmission. CHROMagar Staph aureus (CSA) is a new chromogenic medium for identification of S. aureus on the basis of colony pigmentation. METHODS: The abilities of CSA, thermostable nuclease (DNase), and mannitol salt agar (MSA) to identify S. aureus isolates (n=70) and discriminate between S. aureus and coagluase-negative staphylococci (CoNS; n=8) were compared. RESULTS: CSA proved to be more sensitive and specific than DNase and MSA, allowing a reliable, simple, and rapid method for the identification of S. aureus isolates. All CoNS encountered in this study could be easily differentiated from S. aureus on the medium. The supplementation with 4 microgram/mL of oxacillin allowed simple identification of methicillin resistance in hospital acquired S. aureus strains which show multiple drug resistance profiles. CONCLUSION: CSA proved to be simple and reliable method for the identification of nasal carriers of S. aureus of health care workers.