One-year surveillance of methicillin-resistant Staphylococcus aureus nasal colonization and skin and soft tissue infections in collegiate athletes

Abstract

Objective: To determine the frequency and clinical importance of methicillin-resistant Staphylococcus aureus (MRSA) colonization in student athletes.

Design: Prospective observational cohort study.

Setting: A major university in the southeastern United States.

Participants: Student athletes participating in the men's football and women's lacrosse programs (N = 126). Main Exposure Monthly assessment of S aureus nasal colonization.

Main outcome measures: Trends in S aureus colonization over time and the occurrence of skin and soft tissue infections.

Results: Methicillin-resistant S aureus nasal colonization varied significantly through the athletic season (4%-23%), peaking during times of highest athletic activity. This increase in colonization was not associated with the development of an outbreak of skin and soft tissue infections, and no single MRSA clone emerged as a dominant isolate.

Conclusions: During the athletic season, there is a considerable burden of MRSA colonization in student athletes; however, colonization alone appears to be insufficient to trigger an outbreak of staphylococcal infections. A combination of distinct molecular characteristics in the organism and specific host factors may govern the development of staphylococcal disease.

Figure 1

Staphylococcal colonization (by month) in a men’s collegiate football team. Monthly cultures are divided into spring training (March/April), the off-season (June/July), the regular football season (August-October), and the postseason (December). Monthly results are expressed graphically while aggregate colonization rates are expressed below each season. Double hash marks represent months in which nasal swabs were not performed. The frequency of methicillin-resistant Staphylococcus aureus (MRSA) colonization during the football season was significantly higher than in spring training (16.5% vs 8.4%; P=.003), the off-season (16.5% vs 4.4%; P=.004), and the postseason (16.5% vs 7.7%; P=.04).

Figure 2

Staphylococcal colonization (by month) in a women’s collegiate lacrosse team. Monthly cultures are divided into the preseason (January), spring season (February–April), fall season (September/October), and postseason (November). Monthly results are expressed graphically while aggregate colonization rates are expressed below each season. Double hash marks represent months in which nasal swabs were not obtained. The frequency of methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization was highest in the fall season (23.1%) and lowest in the preseason (11.5%), though differences between seasons were not statistically significant (23.1% vs 11.5%; P=.36).