Nasal Carriage of Staphylococcus aureus and Methicillin Resistant Staphylococcus aureus (MRSA) in Students at the University of Central Oklahoma

Abstract

Nasal carriage of Staphylococcus aureus has been identified as a significant risk factor for subsequent infections and is a target for decolonization approaches. The efficacy of the decolonization methods may be dependent on the load and type of S. aureus present in the nose of individuals in the community. The objectives of this study were to determine the rates of carriage for S. aureus and MRSA, quantify the level of S. aureus and MRSA carriage, and to determine the relatedness of the S. aureus and MRSA isolates recovered from a healthy student population. Nasal swab specimens were collected from 247 healthy University of Central Oklahoma students, serially diluted, and cultured onto blood agar plates containing 4% NaCl for qualitative and quantitative analysis. Methicillin resistance was determined with cefoxitin disk diffusion and PCR for mecA. Relatedness was determined by spa sequence typing. S. aureus prevalence was 21.5% (MRSA 2.4%), with a geometric mean of 1,820 CFU/swab (MRSA 412 CFU/swab). Twenty-two different spa types were identified among the 42 spa positive S. aureus/MRSA positive samples. S. aureus/ MRSA carriage rates were similar to other studies. spa typing revealed a high degree of carriage diversity.