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Methicillin resistant Staphylococcus aureus (MRSA), is a problematic infection which is becoming more common in a variety of athletic related environments. Early recognition, diagnosis, and timely management of infection can help minimize the severity of infection and decrease the rate of transmission. Since most sports physical therapists typically lack adequate knowledge and ability to identify cases of MRSA infection, the pur-pose of this review is to provide a background for associated risk factors, recognition, treatment, and prevention of community associated-MRSA in athletic environments.
The role of the sports physical therapist as a member of the sports medicine team continues to expand, making it critical to increase the knowledge related to non-musculoskeletal issues. Recognition and management of skin infections becomes increasingly necessary in the comprehensive medical care of the athlete. One infection of concern is Staphylococcus aureus, a commonly occurring bacterial species which is moving from nosocomial (hospital based) to community acquired infections found in a variety of athletic related environments.1,2 Staphylococcus aureus is a naturally occurring bacteria found on skin and can be divided into two categories based on its susceptibility or resistance to beta-lactam antibiotics; methicillin susceptible (MSSA) or methicillin resistant (MRSA).3
Methicillin resistant Staphylococcus aureus has been typically associated with healthcare acquired (HA-MRSA) risk factors including recent surgery and hospitalization, indwelling catheter, kidney dialysis, and prolonged stay in long-term care facility (nursing home, hospice).4,5 In the late 1990's, cases of MRSA began to appear in the community (CA-MRSA)6 and athletic related environments.7,8 These athletic related cases had risk factors for acquisition and clinical characteristics distinct from HA-MRSA.5,9–12 Risk factors included participation in contact sports with repeated close physical contact with other competitors, open abrasions, increased use of antibiotics, and sharing of personal equipment.7,8,10,12–15
The medical management of MRSA can be problematic due to low incidence rates, rapid transmission, and limited pharmacological interventions that effectively manage the infection. Low incidence rates of CA-MRSA in athletic environments can delay accurate recognition, diagnosis, and timely management which can increase the risk of infection in other individuals and cause subsequent increase in morbidity. Unrecognized or untreated cases of MRSA can quickly progress to a severe infection requiring hospitalization,16,17 surgery,17 and may lead to death. Selection of appropriate treatment strategies can also be further complicated by the characteristic antibiotic resistance patterns associated with CA-MRSA.5,10 Most sports physical therapists typically lack adequate knowledge and ability to identify cases for physician referral and an understanding of the severity and complications of untreated cases. Since the prevalence of CA-MRSA cases has increased in athletic environments,12–14,18–20 individuals who provide medical care for athletes should have a basic understanding of CA-MRSA infections. Therefore, the purpose of this review is to provide the sports physical therapist with a background for associated risk factors, recognition, treatment, and prevention of CA-MRSA in athletic environments.
A search of PubMed (1966-2006) and Web of Science (1981-2006) was conducted in December 2006, using combinations of the terms, Staphylococcus aureus, methicillin resistant, MRSA, athletic, and sport. The search was limited to articles written in English using human subjects. Fifty articles were obtained in the original search and titles and abstracts were screened for relevance. References were also cross referenced and other relevant literature was reviewed for identification of studies not found using the original search terms. A total of 13 manuscripts ranging from case reports to retrospective cohort studies related to CA-MRSA in athletics were retained.7,8,12–14,16–23
Staphylococcus aureus is a ubiquitous bacteria which can cause infections in patients of any age, race, gender, or economic background and has been found in a variety of settings, regions, and countries.24 Community associated-MRSA has been diagnosed in individuals who participate in contact and non-contact sports from high school to professional levels (Table 1). Reported cases have ranged from 1-13 athletes per team and involved up to 25% of the team.7,8,12–14,16–23 Three common factors implicated in the development of CA-MRSA include exposure to infection, compromised skin integrity, and transmission via direct (person-to-person) or indirect contact (person-to-object).
Swabs from the anterior nares indicate approximately 35% of healthy individuals are colonized with MSSA3,25 and less than 10% are colonized with MRSA.12–14,25 Teens, younger adults, males, and individuals with asthma tend to be the most likely carriers.3,5,25 The high use of antibiotics throughout the year is an additional risk factor for CA-MRSA.12 Increased antibiotic use alters nasal bacterial flora and thus provides a more conducive environment for MRSA colonization.26
Areas of compromised skin integrity serve as an entry portal for a variety of infectious agents. The most common method of transmission is thought to occur when sites of skin injury or abrasion are in direct contact with sites of bacterial colonization.7,8,12–14 Burns associated with athletic surfaces such as turf or wrestling mats7,12,13 are associated with CA-MRSA infections, both near12 and distant to the site of injury.13 Infection tends to occur most often on extremities which are not covered by athletic apparel (elbow, forearm, knee, lower leg).1,12 Unfortunately, areas covered by clothing or protective equipment are also at risk following recent skin trauma due to shaving or abrasions.13 Shaving body areas other than the face (cosmetic shaving) has been shown to increase the risk of infection of areas covered by athletic equipment and clothing.13
The most common method of transmission is direct contact with contaminated individuals.7,8,12–14 A definitive relationship has been demonstrated between CA-MRSA cases and direct contact with infected individuals.7,8,12–14 Risk of infection is thought to be proportional to the frequency and duration of exposure to infected individuals. Prolonged contact usually occurs between athletes on the same team, as well as competitors from other teams who participate in sports with a greater duration of competition (football). This risk is less for athletic events with shorter durations (wrestling).7
American football,1,2,12,14,17–20,22 wrestling,7,20 and rugby8 have been commonly implicated in increased infection rates due to frequent close contact between athletes. Retrospective analysis of cases indicate the highest infection rates tend to occur with positions such as rugby forwards;8 American football linemen,12,14,17 cornerbacks, and wide receivers;13 and wrestlers7 where repeated direct contact occurs throughout competition and practices. It should be noted since CA-MRSA has a low incidence rate, analysis of infection rates by position or sport should be interpreted with caution. Community associated-MRSA has been proposed to be more common in individuals with a higher body mass index (BMI).12 Wrestlers tend to be affected equally across all weight classes7 which contrasts findings that CAMRSA has been associated with higher BMI.12 Findings related to higher BMI in American football may have been due to the association between position (i.e. linemen) and weight. Additionally, wrestlers may be at decreased risk due to strict guidelines involving participation in competition and management of skin infections and open wounds.27
Identification of the source of infection plays a critical role in limiting the spread and thorough management of CA-MRSA. As CA-MRSA infections become more common in athletics, it is possible that individuals who compete against each other could become independently infected with the same strains,12 thus increasing the difficulty to identify the source of infections.
Cases reported in non-contact sports have been associated with shared equipment in facilities such as the locker room or athletic training room.16,20 Even roommates of infected individuals have been shown to be at risk of infection.14,23,28 Cases of MRSA have also been reported in athletes who shared fencing equipment,20 razors,13 towels,12,20 and bar soap.14 Staphylococcus aureus has also been shown to be present in whirlpools and taping gel applicators.12 Common areas in athletic environments which may aid in the transmission of infections include treatment tables, benches, training equipment, and flooring (especially carpeted) in locker rooms, weight rooms, and athletic training rooms. However, other studies have failed to demonstrate a definitive link between MRSA cases and playing surfaces12 or sharing of equipment or facilities.1,2,13,19
The most common presentation of CA-MRSA is in the form of soft tissue lesions such as an abscess or cellulitis.5,6,12,14,15,29,30 Visual inspection offers several clues for identification of CA-MRSA (Figure 1 and and22). Clinically, the lesion and erythema are associated with pain that is out of proportion for the severity of the lesion. Other characteristic signs and symptoms include redness, swelling, warmth, and possible purulent discharge from the lesion site. Lesions are commonly mistaken for a spider bite,15,29 pimple, or boil.12,14 Occasionally, the diameter of the affected area can be as large as 5-7 cm.12
The increased prevalence of MRSA soft tissue infections found in the general population necessitates a low threshold for timely physician referral following the appearance of a lesion that presents with the aforementioned characteristics. The sports physical therapist should contact the physician to facilitate and ensure expedited care. Since recurrent infections are common12,13 the sports physical therapist should have an even lower threshold for physician referral for individuals with a history of CA-MRSA. In the event that the team physician or patient's primary care physician is unavailable for immediate consult, the patient should be directed to an urgent care facility. Until the wound has been formally diagnosed, MRSA should be suspected.
A small, uncomplicated area can be managed using over the counter topical antibacterial ointment (Neosporin), with close monitoring of the concerning lesion for up to 48 hours. The sports physical therapist should be able to gain a sense over 24-48 hours as to whether an area is progressing to something more concerning. Worsening signs or symptoms during the first 48 hours or failure of the lesion to improve within 48 hours warrants immediate physician referral. Any degree of either fluctuance (presence of pus), pronounced erythema, progressive warmth, or increasing pain should raise serious suspicion for infection, particularly in patients who may have been briefly hospitalized during their post-operative period. Surgical wounds should also be monitored in a similar manner.
During the initial management period, the sports physical therapist should stress the importance of wound management and suggest strategies to limit opportunities for exposure to other individuals. Education regarding personal hygiene such as frequent hand washing and daily bathing with antibacterial soap31 or an antimicrobial agent, such as povidone-iodine liquid soap or 4% chlorhexidine, should be encouraged.12,14,15,20,32 Athletes should be required to keep wounds clean and covered to decrease transmission between individuals.13,33 Failure to adequately cover wounds14,15 and multiple contacts with infected individuals further increase risk for infection.7,12 The sports physical therapist should also utilize frequent hand washing or the use of alcohol based gel before and after individual treatment sessions.
A critical step in the specific management of CA-MRSA is recognizing clinical differences between mild skin infections and CA-MRSA infected lesions. Unfortunately, early in the disease process, skin lesions may not present with signs and symptoms suggestive of CA-MRSA. Early intervention is necessary to prevent transmission and progression of infection. The first line of treatment for mild skin infections includes the use of either topical Mupirocin or oral antibiotics directed towards common skin flora.28,34 Topical antibiotics are useful for less severe infections. However, strains of CA-MRSA are resistant to numerous antibiotics, including commonly used beta-lactams, cephalosporins, macrolides, penicillins, and quinolones.5,10 Therefore, if the initial treatment with oral antibiotics is unsuccessful in eradicating pain, swelling, or erythema, the lesion should be excised, drained, and the fluid cultured to direct treatment based on antibiotic sensitivity.5,6,35
Systemic antibiotic use should be reserved for severe infections or mild to moderate infections that cover a large surface area. Large wounds may require hospitalization, surgical debridement, and intravenous antibiotics.17 It is recommended to use an antimicrobial agent that successfully treats a variety of gram positive bacterial infections.28,34 Antibiotics such as clindamycin, sulfamethoxazole/trimethoprim (SMX-TMP), ciprofloxacin, rifampin, vancomycin, or linezolid are appropriate treatment options.19,28,31,34 However, treatment with SMX-TMP and fluoroquinolones have been shown to be associated with higher recurrence rates and are not recommended as first line therapy.28 Most infections resolve in 10 days with appropriate treatment.12 Infections that do not respond to initial treatment regimens or recur should be treated with another group of antibiotics based on antibiotic sensitivity.12,13,30
Obtaining nasal cultures from individuals who may have been exposed to CA-MRSA to determine the presence of infection is questionable.19 Approximately 35% of asymptomatic individuals carry MSSA3,25 and less than 10% of asymptomatic individuals carry MRSA.12–14,25 A positive nasal culture may warrant the use of topical mupirocin if deemed necessary by the treating physician. Topical mupirocin is applied to the nares prophylactically for 5 days to 4 weeks to prevent or limit the spread of infection,19,20,28,30,36 but may not entirely reduce the risk of infection since infection can occur regardless of a positive nasal culture.19
The management of CA-MRSA begins with prevention. Reports of CA-MRSA cases tend to be relatively isolated, yet individuals have been diagnosed in numerous athletic settings.7,8,12–14,18–20 Although CA-MRSA cannot be entirely prevented, best practice measures can be employed to reduce the risk among athletes. The National Athletic Trainers' Association (NATA) and the Centers for Disease Control (CDC) have outlined recommendations (Tables 2 and and3,3, respectively) for the prevention and management of CA-MRSA.20,33 One retrospective study was able to demonstrate a decreased rate of infection after implementing a variety of prevention strategies.17 Future research should determine the effectiveness of these recommendations.
Athletes should be encouraged to use liquid antibacterial soap (3% hexachlorophene or 4% chlorhexidine) for showers immediately after practice and frequently wash hands. Clinicians should also be encouraged to wash hands thoroughly with soap or utilize an alcohol based hand sanitizer, both before and after treatment sessions. Attention to meticulous wound cleanliness and care should be rigorously emphasized. Universal precautions should be employed when treating open skin wounds, which may serve as a reservoir of infection. All wounds should be appropriately covered during and following competition at all athletic events.
Techniques to reduce the frequency of abrasions should be employed, although the use of elbow and knee pads may facilitate infection due to moisture retention conducive to bacterial growth.13 It is recommended that disposable, adhesive mesh strips (Figure 3) be firmly secured to the skin in order to prevent wounds that occur via contact from either playing surfaces or other competitors. Skin irritation may develop in a subset of athletes with sensitive skin secondary to removal of the mesh on a daily basis. Therefore, the decision to use an adhesive mesh should be made on an individual basis.
The practice of sharing personal hygiene products (soap, razors) and sports equipment should also be discouraged. Individual or disposable towels should replace community towels commonly used at practices and games. Towels used in the clinic should be washed in hot water (> 71°C) using detergent and chlorine bleach after each use.32
Athletes should be required to shower immediately following practice before entering the sports medicine clinic or athletic training room. Equipment such as treatment tables and weight room benches should be cleaned and disinfected appropriately after use with a commercial product that contains anti-viral and anti-microbial substances, such as CaviCide® (Unimed-Midwest, Inc., Burnsville, MN).37 Pillow cases and other treatment table linens should be changed following individual treatment sessions and washed in a similar manner as towels. Proper disinfection techniques should also be employed for hydrotherapy (whirlpool) areas. Circulating tubs should be cleaned with an Environmental Protection Agency (EPA) registered disinfectant. The cleaning solution is circulated in the spa for 10 minutes, followed by a rinse with water, and finally air-dried.a37 Non-circulating tubs should be scrubbed, rinsed and drained, sprayed with an EPA registered disinfectant, allow to sit for 10 minutes, rinsed with water, and air-dried.37 Traditional pools, Jacuzzi spas, and exercise pools (Hydroworx or Swimex) use chlorine or ultrasonics to filter and disinfect the pools. Sports physical therapists should be cautious of an athlete with open skin wounds who uses pools. Turbulence can cause skin debridement and subsequent use of towels can produce a source of cross-contamination.
Secondary to the potent virulence and potential adverse sequelae, CA-MRSA is reportable in many states. Outbreaks in confined environments should be closely monitored, but ethical concerns and issues exist when reporting communicable diseases. Individuals and teams may fear the negative stigma associated with a communicable disease.14 Also, the consequences resulting from restricted participation may have implications on win/loss records, and current and future financial incentives (scholarships and contracts) for participation in athletic events. Ultimately, the sports medicine team should determine the time for return to participation that ensures safety of the athlete with CA-MRSA, teammates, and other competitors.
Research regarding CA-MRSA in athletic environments is relatively limited and retrospective designs are typically used to describe prevalence rates and treatment strategies. Due to low incidence rates, systematic tracking using large database programs such as the NCAA Injury Surveillance System (ISS) may help determine treatment and prevention effectiveness. Community associated-MRSA is increasingly prevalent in athletic settings. The sports physical therapists must be aware of risk factors, differential diagnosis, optimal timing for referral, and treatment strategies, while working closely with certified athletic trainers and team physicians. Due to rapid transmission and adverse sequelae of infection (hospitalization, surgery, death), cases of CA-MRSA should not be minimized. Ultimately, prevention is the greatest defense and all members of the sports medicine staff should utilize universal precautions when treating athletes, maintain clean environments within commonly shared areas, encourage proper hygiene practices, and discourage sharing of personal items such as razors, soap, and towels.