Author: Stanforth, Bethany; Krause, Andrew; Starkey, Chad; Ryan, Timothy J
Date published: January 1, 2010
Journal code: PENV
Each year, approximately 12 million Americans visit a physician to be examined for Staphylococcus aureus or methicillin-resistant Staphylococcus Aureus (MRSA) infections (Centers for Disease Control and Prevention [CDC], 2008). MRSA infections total approximately two million annually, resulting in approximately 90,000 deaths and $4.5 billion in health care costs annually. In 2003 MRSA infections were the fifth-leading cause of death in acute care hospitals (Becton, Dickinson & Co., 2008).
MRSA is an evolving pathogen that has morphed into several potentially infectious strains (Shukla, 2006). The Centers for Disease Control and Prevention (CDC) define community-associated MRSA (CA-MRSA) as a strain of MRSA acquired by those who have not been hospitalized or undergone a medical procedure within the past year. CA-MRSA has unique microbiologic and genetic properties relative to health care-acquired MRSA (HA-MRSA), which allow the bacteria to spread more easily therefore causing more skin infections (CDC, 2005). Seventy percent of all MRSA infections are caused by five major strains of MRSA. The most predominant strain in the U. S. is USA 300 (Sampathkumar, 2007). Ninety-seven percent of infections reported from 11 different hospitals were of the USA 300 clone (Herman, Kee, Moores, & Ross, 2008). MRSA is able to survive on a range of surfaces for extended periods of time and can infect hosts even with limited exposure (Salgado, Farr, & Calfee, 2003; Shukla, 2006).
MRSA has recently been found to be capable of penetrating intact skin, allowing the bacteria to infect deeper layers of tissue (Shukla, 2006) . MRSA colonization can persist for months and sometimes years, with a half-life of 40 months (Salgado et al, 2003). Previous studies have indicated that MRSA is commonly transferred through skin-to-skin contact with an infected person, but little is known about a person's likelihood of becoming infected through contact with MRSA-contaminated surfaces (Cohen, 2005). Many risk factors for developing MRSA exist within athletics, including the sharing of clothing, sports equipment, towels, balms, lubricants, razors, and soaps; improper care of skin lesions; and direct skin-to-skin contact with MRSA lesions (Beam & Buckley, 2006). The Indiana Department of Health reported that two wrestling teammates who had never wrestled against one another developed MRSA infections, thus implicating shared items as the source of transmission (CDC, 2003). Of the total cases of 5. aureus diagnosed annually, the proportion of those infected with MRSA rose from 29% in 2001-2002 to 64% in 2003-2004 (McKenna, 2008). A CDC analysis found that 8% to 20% of all MRSA infections reported in hospitals were of the community strain (McKenna, 2008). Thus CA-MRSA is not only of interest to health department sanitarians but to hospital infection control personnel as well.
Athletic-related MRSA cases among athletes are most common in sports involving high levels of physical contact, such as wrestling, football, and rugby (Kirkland & Adams, 2008) . Cases have also been reported, however, among athletes participating in soccer, basketball, field hockey, volleyball, rowing, martial arts, fencing, and baseball (CDC, 2005). Few studies have focused on the presence of MRSA in wrestling environments, where the athletes are potentially at the greatest risk. The first case of MRSA among a wrestling team was reported in 1993 as a forearm abscess (Lindenmayer, Schoenfeld, O'Grady & Carney 1998) . Lindenmayer and coauthors conducted a study from January 1993 through February 1994, tracking the number of MRSA cases reported at a local hospital. During that year, seven of 32 (22%) wrestlers acquired MRSA (Lindenmayer et al., 1998). A recent MRSA prevalence study observed 90% of facilities had two or more positive MRSA surfaces. Nearly half of the 90 surfaces tested (46.7%) produced positive results for MRSA (Montgomery, Ryan, Krause, & Starkey 2010). The purpose of this study was to assess the prevalence of MRSA in rural Ohio high school wrestling environments, including wrestling mats, locker rooms, and athletic health care facilities, to better characterize such environments and their potential for MRSA spread.
Nine rural southeast Ohio high school wrestling and athletic health care facilities were sampled for the presence of MRSA within one to two hours prior to the start of practice; in most cases the mats used for practices are also used for competition. As a general prohibition, street shoes are not permitted on the mats at any time although compliance with this prior to sampling was not ascertained. Ten similar categorical surfaces were sampled using sterile swabs. Composite samples (i.e., multiple swab contacts on a similar category) were collected from the surfaces of treatment tables, the outside and handle of the moist heat unit, athletic training room doorknobs, and the outside and lid of the biohazard container (when present). Wrestling mat samples were taken as a composite sample, from 10 locations distributed evenly throughout the inner circle of the wrestling mat and 30 locations from the larger outer circle (Figure 1). Samples collected in the wrestling locker room were obtained from the doorknob, sink faucets and handles, shower faucets and handles, and the surface of the benches.
The institutional review committee exempted formal review and approval of this study as no human testing took place. The MRSA analytical methods employed in this study are identical to those used by Montgomery and co-authors (2010), and the reader is referred to that study for full details of sampling techniques and colony identification. The same laboratory was used to culture and grow the samples in both studies.
Laboratory surfaces were disinfected before and after sampling to prevent personal or cross-contamination. The swab samples were streaked onto BBL CHROMagar(TM) MRSA plates within 24 hours of collection and prior to the manufacturers expiration date. Plates were incubated at 35°C for 24-48 hours with minimal exposure to light. BBL(TM) CHROMagar MRSA(TM) is a selective and differential medium that uses cefoxitin in order to identify MRSA. Mauve-colored colonies are indicative of positive MRSA samples due to the hydrolysis of the chromogenic substrate (Becton, Dickenson & Co., 2008). The agar plates have a 95% accuracy rate for MRSA when mauve colonies are detected within the first 24 hours of grow out (Flayhart et al., 2005). After incubation for 24 hours, the plates were checked for mauve colonies, and those lacking any were incubated for an additional 24±4 hours. Plates not demonstrating mauve colonies by 48 hours were reported as negative for MRSA. The computer software SPSS, version 15.0, was used to process descriptive statistics and frequencies.
CA-MRSA strains were detected on wrestling mats and athletic training room surfaces. All nine (100%) of the sites tested had at least one positive sample for the presence of MRSA. The inner and outer circles of wrestling mats displayed the greatest prevalence of MRSA (89%), while the doorknobs of the athletic training room were the least common site of MRSA detection (22%) (Table 1). Of the 31 available sites sampled in the athletic training facilities, 14 (45%) were positive for CA-MRSA; in the wrestling area, 36 of the 54 (67%) of the samples produced positive results (Table 2). The prevalence of MRSA by sampling surface category is depicted graphically in Figure 2.
Some schools have the mats rolled at night, while some are stacked, and others are simply left as they are. Although mats are supposed to be routinely cleaned and stored in a hygienic manner, we could not determine in the course of our study what the true practices were in each facility except to note that a consistent approach was clearly not implemented across all facilities. Thus, the effect of storage and outside traffic fic on these results could not be definitively ascertained.
The prevalence of MRSA by school varied greatly ranging from 10% to 88% (Table 2). At the school with the least frequent MRSA detection ("H"), only the wrestling benches were positive (Figure 3). The majority of the schools ranged from 40% to 56% of surfaces being positive for MRSA. Data indicate that the following three surfaces have the highest percentage of MRSA detections: inner circle of the wrestling mats, outer circle of the wrestling mats, and the biohazard container (when present). Schools A, F, and G, however, lacked a distinct biohazards waste container, therefore no samples could be collected in that category. This data demonstrates that locker room benches and sinks were found to be more frequently contaminated than waste containers (Figure 3). The inner and outer circles of wrestling mats were found to have a perfect Pearson's correlation (r = 1.0), indicating there was no significant difference between inner and outer ring contamination rates.
In comparing locations, great MRSA variability is evident. One school had seven out of eight surfaces test positive for the presence of MRSA (88%), while another had only one of 10 (10%) surfaces test positive. These results demonstrate variability in the presence of MRSA among high school wrestling facilities, yet are consistent with the variability in total numbers of positives reported by Montgomery and co-authors (2010). Since cleaning and decontamination procedures at the various schools were not examined in the project, it is not precisely clear what explains this wide range of MRSA prevalence. Plausible explanations include sampling variability, hygiene practices at the schools (i.e., 33% of the schools lacked a designated biohazards container), time between sampling and last cleaning at the schools, and actual MRSA prevalence differences.
A high prevalence of MRSA occurred in the inner and outer circles of wrestling mats (89%), strongly suggesting that high school wrestlers are exposed to an elevated risk of surface-contact MRSA colonization and infection. The sitting surfaces of wrestling locker room benches also displayed a high prevalence of MRSA (78%). As this is considered to be a high traffic area (all wrestlers are in contact with the benches on a daily basis), the risk of contamination reinforces the CDCs recommendation for proper and frequent cleaning of these surfaces.
Data reinforce the presumption that the risk of MRSA contamination is not limited to surfaces with which only wrestlers come into contact. An additional threat of MRSA contamination arises from other surfaces and equipment present in the athletic training facility. Biohazard containers had the greatest prevalence of MRSA of surfaces found within the athletic training room (83%), and treatment tables also displayed a frequent presence of MRSA (56%). Such findings illustrate the heightened likelihood of all student athletes and health care providers in the high school coming into contact with MRSA from such shared facilities. Therefore it is possible for athletes to transfer MRSA from one individual to another, with the treatment tables serving as the transmission medium. This reinforces the crucial need to maintain frequent and proper cleaning regimens of all surfaces within the athletic training facility, especially high traffic surfaces such as treatment tables.
CDC recommendations to prevent MRSA infections include proper personal hygiene, washing hands often, showering immediately following exercise, and washing uniforms and clothing after each use. It is also important to not share any personal items and to take proper care of skin, including wearing protective clothing and covering all abrasions and lacerations (CDC, 2005). The awareness level of facility users relative to the CDC guidelines was not determined in this study. Future studies might explore student athletes' knowledge of MRSA risks and prevention safeguards, and athletic trainer and coaching staff attitudes regarding the need for proper hygiene. The opportunity exists for the study of sanitarian or health educator interventions directed at the general MRSA-affected population in schools with athletic facilities and-by extension- community recreation centers.
Although not expressly studied here, it was anecdotally noted that a wide variety of cleaners, sanitizers, and detergents were utilized across the facilities. In order to prevent MRSA from spreading via use of athletic equipment and facilities it is imperative to follow proper cleaning regimens. Facilities should be kept clean and cleaning procedures should be reviewed with environmental services staff to ensure that CDC guidelines are being met. Surfaces that are most commonly touched should receive more frequent cleaning. Detergents and disinfectants registered by the U.S. Environmental Protection Agency (U.S. EPA) as effective against MRSA should be used to clean surfaces. It is important to follow all instruction labels of all cleaners and disinfectants, paying particular attention to the amount of contact time each product must have on surfaces in order to be effective. The rigor with which such practices are followed would make for a timely and significant follow-up study to the findings reported here.
Gonzaga and co-authors recommend disinfecting wrestling mats and other commonly shared environments with an alcohol-based sanitizers consisting of Chlorhexidine or triclosan (Gonzaga, Mortimer, Wolinsky & Rammelkamp, 1964). The addition of Chlorhexidine to alcohol is known to intensify its bactericidal effects (Elston, 2007). The National Federation of State High School Associations requires disinfecting wrestling mats prior to use as well as laundering mops, towels, and athletic gear on a daily basis (National Federation of State High School Associations, 2007).
These findings support the premise that high school wrestlers are frequently exposed to several potential MRSA contact points. Nine of the 10 high schools sampled had at least one positive result for MRSA; at two schools, 80% of the locations tested were positive for MRSA, another two schools were positive at 70% of the locations, and three were positive at half of all locations tested. Of the locations that wrestlers were most likely to have bare skin contact with - the inner circle of the wrestling mat, the outer circle, and locker room benches - most were positive for MRSA in the majority of the samplings.
Athletes at the schools that were sampled compete against one another regularly throughout the season. Further research could determine if the same strain of CAMRSA is being transmitted from one team to another, therefore spreading MRSA among different schools. This information could further aid in the prevention and reduction of outbreaks, and could be of use to sanitarians and associated public health officials for both managing CA-MRSA cases and in controlling the chain of infection.
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Bethany Stanforth, LAT, ATC
Andrew Krause, PhD, LAT, ATC
Chad Starkey, PhD, LAT, ATC
Timothy J. Ryan, PhD, CIH, CSP
Corresponding Author: Timothy J. Ryan, Associate Professor & Environmental Health Sciences Program Coordinator, E344 Grover Center, Ohio University, Athens, OH 45701-2979. E-mail: firstname.lastname@example.org.