April 28, 2016
3 min read

MRSA carriage prevalent among asymptomatic athletes

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A recently published literature review suggests approximately 8% of athletes and 13% of collegiate athletes in the United States may be asymptomatically colonized with MRSA.

In addition, carriage was far more prevalent among collegiate wrestlers than other athletes, according to the data, and colonized athletes were more than seven times as likely than noncarriers to develop MRSA skin and soft tissue infections (SSTI).

“[Community-associated MRSA (CA-MRSA)] infections have become increasingly problematic among healthy, asymptomatic individuals,” researchers from the Warren Alpert Medical School of Brown University wrote. “Athletes are particularly vulnerable to CA-MRSA infection population because of the frequency of skin trauma, close contact situations and sharing of equipment that is customary in the athletic setting. However, there is a lack of aggregate data on large athletic populations, and there is ambiguity in the literature regarding the potential of MRSA colonization to cause MRSA infection among athletes.”

To address these deficiencies, the researchers conducted a systematic review of published data examining MRSA among asymptomatic athletes. Studies eligible for analysis were required to differentiate between carriage and infection, detail the site of colonization and include the microbiological method of MRSA detection used. Considered studies were independently evaluated by two reviewers, with MRSA prevalence and RR of ensuing SSTI serving as the primary and secondary outcomes of interest, respectively.

Of the 382 relevant studies identified by the researchers, 15 met analysis criteria. The pooled prevalence of MRSA colonization among the 1,495 included asymptomatic athletes and team staff was 5% (95% CI, 1-13), but increased to 6% (95% CI, 1-13) when analyzing athletes alone. Colonization prevalence among American athletes — on whom most of the included studies reported — was 8% (95% CI, 2-17).

Data from eight of the studies indicated prevalence to be greatest among collegiate athletes (13%; 95% CI, 4-25), while the four studies examining professional athletes suggested a 0% prevalence rate (95% CI, 0-3). Stratifying collegiate data by sport, the researchers found an 8% colonization rate among basketball (95% CI, 0-28) and football players (95% CI, 3-15), and a 22% rate among wrestlers (95% CI, 0-85). The most common strains among athletic team members, as determined by pulsed-field gel electrophoresis, were USA300 (22%) and USA400 (18%). In addition, the researchers determined that colonized athletes and team members were 7.37 times more likely to develop MRSA SSTI than those who did not carry the pathogen (95% CI, 2.47-21.94).

According to the researchers, these data suggest the MRSA colonization rate among asymptomatic athletes is more than triple that of the general population, as well as a prevalence among collegiate athletes nearly twice that reported by ICU patients. These findings, they continued, would support additional investigation of decolonization programs specifically designed for young adults in the athletic setting.

“Until such protocols are developed, evaluated and implemented, the high incidence of MRSA colonization and the sevenfold increase in the risk of MRSA SSTI should prompt the discussion of implementing MRSA surveillance in athletes (such as the collegiate athletes of high-risk sports), followed by decolonization efforts, environmental surveys and regularly occurring physical examinations of colonized patients over the course of the season in order to break the vicious circle of MRSA colonization-infection-transmission in this setting.”

High school wrestlers frequently contract skin infections

This high prevalence of MRSA carriage among wrestlers reported by the Brown researchers came shortly after another study associating the sport with an increased rate of skin infections.

Teresa R. Johnson, PhD, of the department of medical education at the University of Central Florida College of Medicine, and colleagues gathered skin infection data from the National High School Sports-Related Injury Surveillance Study from the 2009-2010 to the 2013-2014 school years. The rates of infection were calculated by comparing the amount of athlete-exposures to the amount of injuries, and included any skin-related infection that resulted in time lost from participation in athletic activities.

Teresa Johnson

Teresa R. Johnson

Study data showed that of the nearly 21 million athlete exposures recorded during the study, 474 skin infections were reported, for a prevalence rate of 2.27 per 100,000 athlete exposures. Almost 74% of the skin infections occurred in wrestlers, with an incidence rate of 28.56 per 100,000 athlete exposures. Football, which accounted for 17.9% of skin infections, showed an incidence rate of 2.32 per 100,000 exposures. In addition, skin infections made up 1.2% of all sports-related injuries recorded, but constituted 12.4% of all wrestling injuries.

“Skin infections are common in high school sports and in some sports can result in significant time loss from participation. Thus it is of utmost importance to understand rates and patterns of skin infections in high school athletes in order to drive effective evidence-based prevention efforts,” they wrote. – by Dave Muoio

Disclosure: The researchers report no relevant financial disclosures.