This report is the first of recurring CA-MRSA SSTIs in a football team during consecutive seasons. From 2 cases in 2002 to an outbreak involving 11 players in 2003 and then 1 case in 2004, we have shown that eradicating these infections is difficult once they become established in a football team. Infections were likely propagated year to year from previously infected players, and they appear to be susceptible to recurring colonization and infection themselves.
Consistent with other reports, our findings implicate sharing personal items and improper wound care as risk factors for CA-MRSA infections (17
). While the concept is counterintuitive, soap sharing was also associated with MRSA infections in a prison outbreak (19
). Therefore, teams should consider switching to liquid soaps in an outbreak situation and always provide prompt wound care.
Linemen were identified as a high-risk subgroup. They engage in frequent and aggressive skin-to-skin contact during games, similar to hand-to-hand combat maneuvers as reported in a military MRSA outbreak (20
). In addition, linemen tend to be physically larger than their teammates. Increased body mass index and lineman position were risk factors for CA-MRSA infection in another football team outbreak (18
Two recent reported CA-MRSA outbreaks in football teams detected no nasal carriage in their combined cohort of 182 football players (17
). In contrast, we document a high MRSA nasal carriage rate (8%) among team A players even while hexachlorophene showers were provided. The actual carriage rate might be higher, since we obtained nasal cultures after all case-players had begun antimicrobial treatment. Additional case-players may have been carriers as well, but they may have been decolonized before culture. Further research is needed to study the association between nasal carriage of CA-MRSA and SSTI to develop decolonization guidelines. The data facilitated a carrier-control study. Similar to risk factors for infection, nasal acquisition of CA-MRSA is associated with sharing personal items, particularly in the locker room.
Crowded living conditions during training camp appear to facilitate the acquisition of CA-MRSA, which then propagates in on-campus housing. Investigators of an outbreak among military recruits found an association between having a roommate with an SSTI and MRSA infection (21
). Consequently, players' living arrangements should be as dispersed as possible.
Unique to our investigation are 1 confirmed and 2 presumed community-associated strains of MRSA. We presented laboratory results indicating that the outbreak strain was likely the USA300 genotype. Since we do not have PFGE results from 6 case-players, different strains could have caused those infections. However, a multiclonal outbreak is unlikely, since other MRSA SSTI outbreaks in Los Angeles County among soccer players, men who have sex with men, jail inmates, and newborns have been exclusively due to the USA300 strain (14
; Los Angeles County Department of Health Services, unpub. data). In contrast, our limited data do not suggest a clonal spread of MSSA on this team. Multilocus sequence typing was not available locally, which prevented further characterization of the isolates.
Selection bias of case-players and controls is a limitation of this study. Enrollment of players with uncultured infections and those without PFGE results introduces the possibility of misdiagnosis and misclassification. Most football teams assign jersey numbers on the basis of field position. Therefore, our control selection method might not have captured a representative sample of the team. However, the distribution of field positions among controls and the entire team appears similar (). The small sample size produces less precise (wide confidence intervals) results and prohibits more in-depth multivariate analyses. Reporting bias is possible, since players and the team fear negative publicity, and we do not have data on risk factors during the off-season. In order to maintain confidentiality, we were unable to interview several players because of high media scrutiny.
As CA-MRSA strains become more prevalent in the community (23
), SSTIs will likely continue to afflict football players. Despite comprehensive infection control interventions, sporadic cases of MRSA SSTIs continue to occur on this team. However, a recurrent outbreak was averted in the latest season likely because of increased vigilance to proper hygiene practices and awareness of this disease among the staff and players.