Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a disease-causing organism that has been present in hospital settings since the 1960s. However, a genetically distinct strain of MRSA, called community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA), has emerged in recent years in community settings among healthy individuals. While this organism has been found to be less resistant to antibiotics, it is also more virulent and capable of causing a spectrum of illnesses. School nurses must be aware of the risk factors for this infection and understand its signs, symptoms, diagnostic testing, and management. With this knowledge, school nurses can help protect students, staff, and community members from this increasingly prevalent pathogen.
INTRODUCTION
Staphylococcus aureus is a microorganism that was first identified in the 1880s. Today it is the leading cause of infection among hospitalized patients in the United States (Noskin, Rubin, & Schentag, 2005). This organism grows best in moist, warm, dark environments. On human skin it is most often found in the nares, groin, and axilla. The antibiotic penicillin was discovered in 1941 and subsequently used to treat infections arising from staphylococcus aureus. By the 1960s, widespread use of penicillin led to antibiotic resistance, leading to the development and use of the antibiotic methicillin (Zetola, Francis, Nuermberger, & Bishai, 2005). Soon after that, methicillin-resistant Staphylococcus aureus (MRSA) became prevalent in hospital settings. MRSA is resistant to beta-lactam antibiotics, including penicillin, ampicillin, amoxicillin, methicillin, oxacillin, and dicloxacillin. This pathogen is also resistant to cephalosporins, carbapenems, and monobactams (Drews, Temte, & Fox, 2006).
Since the late 1990s, a genetically distinct strain of MRSA has emerged in community settings among healthy individuals who have not had contact with health care facilities (Rybak & LaPlante, 2005; Kendig, 2004). This new strain, called community-acquired MRSA (CA-MRSA), is seen primarily among healthy children and adults. Rates of infection from this organism continue to rise. Outbreaks of CA-MRSA infections have been seen among children and young adults (Drews, Temte, & Fox, 2006), particularly in day care centers and among student athletes who participate in contact sports, such as football and wrestling (Rybak & LaPlante, 2005).
Like MRSA, the CA-MRSA organism is colonized on the skin, mucous membranes, and nares of healthy people in the population. Because healthy immune systems and intact mucosa and skin prevent penetration of the organism, only a small percentage of those colonized actually develop the infection (Johnson & Saravolatz, 2005). However, colonized individuals can be asymptomatic carriers. Most often, CA-MRSA is transmitted from person to person by contaminated hands. People with persistent nasal colonization can also spread the infection via droplet transmission, particularly if they develop a respiratory infection (Calfee, Durbin, & Germanson, 2003). Such droplet transmission can lead to community-acquired pneumonia. CA-MRSA is also transmitted via contact with inanimate objects contaminated with body fluids containing the organism, which can survive for hours to days on these objects (Neely & Maley, 2000). Infection occurs when the bacteria enters the body and is not destroyed by the immune system.
CA-MRSA causes mild to severe skin and soft tissue infections. The infection is manifested locally by redness, warmth, induration, and pain. Systemically, individuals can experience general malaise, fever, chills, and night sweats. If the infection is not diagnosed promptly or treated inappropriately, life-threatening illnesses can result, including osteomyelitis, endocarditis, septic arthritis/bursitis, necrotizing pneumonia, necrotizing fasciitis, bacteremia, septic shock, and death (Jerome, 2005; Noskin, Rubin, & Schentag, 2005). Such advanced cases of CA-MRSA require hospitalization and aggressive medical intervention that can include surgical debridement and skin grafting (Naimi, LeDell, & Como-Sabetti, 2003).
While hospital-acquired MRSA harbors a gene that resists many antibiotics, the CA-MRSA strain is less resistant to antibiotics. CA-MRSA infections can be treated with most antibiotics other than beta-lactams and erythromycin (Zetola, Francis, Nuermberger, & Bishai, 2005; Chalrebois, Perdreau-Remington, & Kreiswirth, 2004). However, in contrast to MRSA, CA-MRSA produces a toxin that can lead to severe infection in otherwise healthy children and adults (Drews, Temte, & Fox, 2006). CA-MRSA strains also multiply much faster than hospital MRSA strains (Rybak & LaPlante, 2005). These factors have led to an increased prevalence of CA-MRSA nationwide (Jerome, 2005).
Risk Factors for CA-MRSA
Hospital-acquired MRSA commonly occurs in people with the following risk factors: a history of current, recent, or long-term hospitalization; prolonged antibiotic use; and intravenous drug use. In contrast, factors associated with risk of CA-MRSA infection include the following: close skin-to-skin contact with a person infected with CA-MRSA, loss of skin integrity allowing entry of the bacteria into the body, contact with contaminated items and surfaces, crowded living conditions, sharing personal items, poor hygiene, having a history of ectopic dermatitis, and exposure to family members or friends who work in a health care setting (Campbell, Vaughn, & Russell, 2004). Several studies have identified a number of risk factors for CA-MRSA among student athletes. These include playing contact sports, experiencing skin abrasion and trauma, having a higher body mass index (BMI), participating in cosmetic body shaving, coming into physical contact with a person who has a draining lesion or is a carrier of MRSA, and sharing equipment that is not cleaned between users (Kazakova, Hageman, & Matava, 2005).
Assessment of CA-MRSA
Taking into account the risk factors for CA-MRSA infection, this diagnosis should be considered by the school nurse in all students who present with signs of skin and soft tissue infection. The school nurse has an even higher index of suspicion for CA-MRSA when providing care to those with persistent skin and soft tissue infections who have had a poor response to treatment with beta-lactam antibiotics (Rybak & La-Plante, 2005). School nurses must engage in careful surveillance of those students who have come into direct contact with CA-MRSA infected individuals. Also, a particular recommendation for the school nurse is to consult with local health departments to determine if there is a high prevalence of CA-MRSA in the local community (Kendig, 2004).
School nurses must engage in careful surveillance of those students who have come into direct contact with CA-MRSA infected individuals.
Students may initially seek consultation with the school nurse with complaints of having a sore attributable to a spider bite. The lesion, which often occurs spontaneously, may appear as a pimple or boil. It can be red, swollen, painful, and have purulent drainage. Particular attention is paid to students who have the following skin and soft tissue infections: pustular lesions, furuncles, carbuncles, deep folliculitis, abscesses, or infected wounds. All skin lesions should also be examined carefully for the following presentations: (a) cellulitis, in which the tissue is swollen, reddened, hot, and tender, (b) fluctuance, in which the presence of pus causes a soft, boggy feeling on palpating the skin, and (c) crepitus, in which the presence of air from gas-forming infection causes a crackling or grating feeling on palpating the skin (Zetola, Francis, Nuermberger, & Bishai, 2005). Such findings require immediate referral by the school nurse to the primary care provider or emergency department.
Diagnostic Testing and Management
Prompt diagnosis of CA-MRSA has often been limited because of a lack of awareness among providers about this organism as a cause of skin and soft tissue infection. In the past, skin infections have been treated with over-the-counter triple antibiotic ointment or with a standard course of oral antibiotics. Health care providers did not routinely order cultures to identify the organism and antibiotic susceptibility profile unless the infection appeared extensive or the initial treatment was unsuccessful. However, cultures and susceptibility testing need to be done with CA-MRSA infections as they cannot be diagnosed based solely on the appearance of the lesion (Zetola, Francis, Nuermberger & Bishai, 2005).
The majority of CA-MRSA infection is of mild to moderate severity and is treated in the outpatient setting. However, school nurses must be alert to the fact that even mild cases have the potential to develop into invasive infection. Students are classified as having a mild infection when they are afebrile with a relatively small (less than 5 cm) lesion. Incision and drainage of the lesion, without oral antimicrobial therapy, can be an adequate treatment strategy in some of these cases (Drews, Temte, & Fox, 2006).
The majority of CA-MRSA infection is of mild to moderate severity and is treated in the outpatient setting. However, school nurses must be alert to the fact that even mild cases have the potential to develop into invasive infection.
Students are classified as having a moderate infection when they have fever, stable co-morbidities, or abscesses greater than 5 cm in diameter. These students require oral antibiotic treatment. Incision and drainage is the initial step in the management of abscesses and furuncles that contain pus. Purulent material should be collected and sent for culture and susceptibility testing. If CA-MRSA is suspected, the student is empirically started on a non–beta-lactam antibiotic while culture results are pending. When the causative pathogen is identified by testing, treatment is adjusted based on these results (Kendig, 2004).
Treatment choices for mild-moderate infection include clindamycin, trimethoprim-sulfamethoxazole, or a fluoroquinolone. Doxycycline and minocycline are other antibiotics that may be prescribed by the provider; however, these antibiotics are avoided in children younger than eight years of age (Bell, 2006). School nurses are cognizant of the most common side effects of antibiotics, including nausea, diarrhea, rash, and allergic reaction.
Students with severe CA-MRSA skin and soft tissue infections include those with large or multiple furuncles, abscesses, cellulitis, systemic disease, and those with medical comorbidities who are at high risk for serious complications. These students are hospitalized and receive intravenous antibiotic therapy. Vancomycin is generally considered the drug of choice for severe CA-MRSA infections. Surgical intervention and infectious disease consultation may also be necessary (Rybak & LaPlante, 2005).
Infection Control Considerations
Infection control is an essential component of school nursing practice. Several strategies can be instituted to decrease the incidence of CA-MRSA in the school setting. In general, personal hygiene is essential. Hands are the main source of transmission of infection; therefore, hand washing is the most important way to prevent the spread of infection. Students participating in school athletic programs are encouraged to shower with soap and hot water after participating in contact sports or after sharing exercise or athletic equipment. Students should be discouraged from sharing personal items such as soap, towels, razors, and clothing or uniforms that can be contaminated with CA-MRSA. Gym teachers, athletic coaches and trainers must establish a cleaning schedule for shared equipment. The surfaces of shared equipment should be washed before and after each use with a disinfectant such as Hibiclens, bleach, or a commercial household disinfectant. To decrease transmission, a towel or layer of clothing can be used as a barrier between the body and surfaces of shared equipment such as benches and exercise machines (Cohen, 2005).
The school nurse must use contact precautions with all students suspected of CA-MRSA infection; this includes using gloves and cleaning all potentially contaminated surfaces. The school nurse’s examination room must be carefully cleansed with a diluted bleach solution or an Environmental Protection Agency (EPA)-registered disinfectant designed for general housekeeping purposes. All direct care items and potentially contaminated surfaces should be cleaned and disinfected after the student is examined. Drainage from CA-MRSA wounds is highly infectious. The school nurse should wear clean, nonsterile gloves when implementing wound care or doing dressing changes. After contact with the student, gloves must be removed, followed by hand washing with an antimicrobial agent. Students are taught to keep infectious lesions covered with clean, dry bandages.
To reduce the potential of spreading CA-MRSA to others, students with this infection are excused from gym class, athletic practice, and competitions until the lesion is healed (Cohen, 2005). Some authors recommend that coaches inspect the skin of exposed and infected athletes prior to athletic participation (Kazakova, Hageman, & Matava, 2005). This can be done in collaboration with the school nurse, who can monitor skin integrity and healing from the time of diagnosis. Members of the school community recognize that these recommendations may lead some students to be hesitant to report signs of an infection. Nevertheless, coaches and school nurses must emphasize to students the importance of reporting suspicious skin lesions and complying with treatment and infection control recommendations. School nurses are in an ideal position to educate teachers, coaches, parents, and students about the strategies to manage CA-MRSA infection. Helpful resources for such teaching are available on the Centers for Disease Control and Prevention Website at the following link: http://www.cdc.gov/ncidod/dhqp/ar_mrsa_ca_public.html.
. . . coaches and school nurses must emphasize to students the importance of reporting suspicious skin lesions and complying with treatment and infection control recommendations.
Table 1 lists additional information that can be provided to staff, students, and families in order to prevent the spread of CA-MRSA infections. In addition to these measures, school nurses should report cases of CA-MRSA to the local health department and carefully monitor for this infection among other students in the school.
CONCLUSION
The emergence of CA-MRSA infections is an additional threat to the growing global public health crisis of antimicrobial resistance. Efforts to control MRSA infections can no longer depend only on surveillance, infection control efforts, and cautious antibiotic prescribing practices within the hospital setting. Proactive education, aggressive diagnostic efforts, and effective treatment for CA-MRSA infections will not only improve care but also protect other individuals, health care providers, and the community from this increasingly prevalent pathogen. Early detection and treatment of CA-MRSA is essential in preventing the spread of infection to others in the community.