Characteristics of airborne Staphylococcus aureus (including MRSA) in Chinese public buildings

The aim of this study was to evaluate the concentration and size distribution of airborne culturable Staphylococcus aureus (S. aureus) (including MRSA) in Chinese public buildings. Air samples were collected, using six-stage Andersen sampler from five different public buildings in one large Chinese community. The mean indoor concentrations of the total and respirable airborne S. aureus were 72 and 50 CFU/m³ in the general hospital, 72 and 49 CFU/m³ in the kindergarten, 76 and 52 CFU/m³ in the hotel, 84 and 57 CFU/m³ in the movie theater, and 55 and 40 CFU/m³ in the university classroom. Respirable S. aureus amounted to approximately 57-73 % of the total S. aureus concentrations. Mean total and respirable concentrations of airborne MRSA were 32 and 20 CFU/m³ in the general hospital, 20 and 13 CFU/m³ in the kindergarten, 23 and 16 CFU/m³ in the hotel, 33 and 20 CFU/m³ in the movie theater, and 24 and 17 CFU/m³ in the university classroom. Respirable MRSA amounted to approximately 61-72 % of the total MRSA concentrations. The ratios of indoor and outdoor concentration for airborne S. aureus and MRSA were more than 1.0 in all the investigated public buildings. The size distribution results showed relatively high collection rates on stage 4 (2.1-3.3 μm) for both airborne culturable S. aureus and MRSA regardless of the type of public buildings.