An outbreak of borderline oxacillin-resistant Staphylococcus aureus (BORSA) in a dermatological unit

From February through July, 2000, there was an accumulation of mecA-negative borderline resistant Staphylococcus aureus (BORSA) in the Department of Dermatology. BORSA was isolated in 37 samples from 11 patients. The isolates were typed by antibiogram, phage type, pulsed-field gel electrophoresis (PFGE), and spa genotyping that confirmed that they were indistinguishable from one another. In May, 2000, an intervention was initiated focusing on infection control. In-patients with BORSA were discharged and antibiotic treatment was stopped, if possible. Emphasis was put on disinfection of shared utensils and individualization of previously shared creams and lotions. After the intervention, BORSA was isolated from another 3 patients before the outbreak was terminated. A case-control study was undertaken to identify possible risk factors for being a BORSA patient. Compared to the controls, the patients with BORSA had more severe skin disease, were more often hospitalized, and had more bed days.