Characteristics that promote transmission of Staphylococcus aureus in German nursing homes

OBJECTIVE: To determine factors that influence transmission of Staphylococcus aureus in nursing homes in the Rhine-Neckar region of southern Germany. DESIGN: Ecologic study. SETTING: Forty-seven nursing homes in the region. PARTICIPANTS: Residents of the approached nursing homes who agreed to participate. METHODS: Personal data and swabs of the nares were collected from participants. Swabs were examined for growth of S. aureus. All S. aureus isolates were typed using pulsed-field gel electrophoresis (PFGE). Transmission rates were calculated by dividing the number of transmissions (ie, cases in which two inhabitants shared the same PFGE type) by the number of S. aureus carriers. Characteristics of the nursing homes were correlated with a home's transmission rate. RESULTS: In each nursing home, 12% to 54% of the residents were colonized with S. aureus. The transmission rates for the 47 nursing homes ranged from 0% to 70%. A linear regression model revealed that a stay in the nursing home of longer than 6 months and accommodation in a room with 3 or more beds were positively associated with the transmission rate. Receipt of antibiotics during the 4 weeks preceding the study was negatively associated with transmission. CONCLUSIONS: Stays beyond 6 months and accommodation in rooms with multiple beds are important for the transmission of S. aureus. One way to reduce transmission would be to design facilities with single and double rooms. However, the social needs of the residents must be evaluated and respected.