Isolation of airborne oxacillin-resistant Staphylococcus aureus from culturable air samples of urban residences.
Culturable single-stage impactor samples were collected onto nutrient agar in kitchen and bedroom areas of eight urban and four suburban residences in Philadelphia, Pennsylvania. Staphylococcus aureus colonies were identified by replica plating of the original impactor samples onto Chapman Stone medium followed by isolation of up to eight colonies for coagulase testing. Kirby-Bauer disk diffusion method was utilized to evaluate S. aureus resistance to both oxacillin and cefaclor. The median concentrations of total culturable bacteria observed in bedrooms and trash areas were 300 CFU/m(3) and 253 CFU/m(3), respectively. Median culturable Staphylococcus spp. concentrations in bedrooms and trash areas were 142 CFU/m(3) and 204 CFU/m(3), respectively. A total of 148 individual S. aureus colonies were isolated and tested for antibiotic resistance. Cefaclor resistance was encountered among only 6 of the 148 (4%) colonies. Nearly one-quarter of all S. aureus isolates tested displayed resistance (n = 30) or intermediate resistance (n = 5) to oxacillin. Twenty-six percent (n = 20) of trash area isolates and 21% (n = 15) of bedroom isolates displayed resistance or intermediate resistance to oxacillin. The median difference in percent resistance between trash and bedroom areas was 10% (p = 0.1). Results suggest that there may be a systematic difference in bacterial populations between downtown and suburban residences. Storage of household waste and handling of food may contribute to presence of the organism in the air of residences.
School of Public Health, Department of Environmental and Occupational Health, Drexel University, Philadelphia, Pennsylvania 19102-1192, USA. hrp22@drexel.edu
Hernando R
HR
Perez
Rachel
R
Johnson
Patrick L
PL
Gurian
Shawn G
SG
Gibbs
Jennifer
J
Taylor
Igor
I
Burstyn
D000393:Air Pollutants / Q000302:isolation & purification; D001431:Bacteriological Techniques; D004781:Environmental Exposure; D004784:Environmental Monitoring; D006798:Housing; D006801:Humans; D016106:Methicillin Resistance; D010068:Oxacillin; D013211:Staphylococcus aureus / Q000302:isolation & purification*; D013383:Suburban Population; D014505:Urban Population
D000393:Air Pollutants; D010068:Oxacillin