• Introduction
• Treatment
• Eradication of Carriage
• Infection Control Measures
• Conclusion

Introduction

Staphylococcus aureus (SA) is a bacterium commonly found on the skin or anterior nares in the nose of healthy individuals. Although SA often colonizes humans without causing disease, it can be responsible for minor to life-threatening infections of the skin, bone, blood, heart valves, and lungs. SA is easily spread by contact with the skin of a person infected or colonized with the bacteria. SA can also be acquired from the hands of health care workers or inanimate objects that have been in contact with a person carrying the organism.

Nursing homes and other long-term care facilities have been identified as reservoirs of MRSA. Over the past decade, MRSA has also emerged as a cause of skin and soft tissue infections in the community. Most MRSA infections are minor infections of the skin that take the form of pustules, furuncles or boils. Generally, these conditions are mild, self-limited, and do not require aggressive treatment. Not surprisingly, this organism is now being increasingly recognized as a cause of infections in residents of jails and prisons. In the correctional setting, staphylococcal skin lesions have often been mistakenly attributed to spider bites. In reality, spiders rarely bite people, and most of the bites are inconsequential.

Once community-associated methicillin-resistant SA (CA-MRSA) has a foothold in a correctional facility, it is likely to remain there indefinitely. For every identified colonized or infected inmate or staff member, there are many who are not identified. Control of outbreaks relies upon reducing the bacterial load in a facility by treating identified cases, decreasing the likelihood of bacteria being passed between individuals, and decreasing the size of the inoculum when bacteria are transmitted.

Penicillin resistance in SA is due to the production of beta lactamase, an enzyme that breaks down penicillin's beta lactam ring and renders the drug inactive. Within a few years of the first clinical use of penicillin in the 1940s, resistance due to beta lactamases was identified. Within a year of the introduction of the semisynthetic, beta lactamase-stable, penicillin methicillin in 1960, MRSA strains were identified. By the 1990s, over half of SA isolated in some hospitals were MRSA.

Methicillin resistant strains are resistant to all beta lactam antibiotics, including penicillins and cephalosporins. In addition, MRSA strains often carry plasmids that lead to resistance to aminoglycosides, fluoroquinolones, macrolides, and chloramphenicol. Many MRSA strains are susceptible to trimethoprim-sulfamethoxazole, clindamycin, and rifampin. Virtually all SA are fully susceptible to vancomycin. However, the first clinical isolate of SA with reduced susceptibility to vancomycin was reported from Japan in 1996. The first documented case of infection caused by vancomycin-resistant S. aureus (VRSA) (vancomycin MIC >32 µg/mL) in a patient in the United States was reported in 2002.

Even though SA infection may be suspected, cultures and sensitivities are required to confirm the diagnosis of MRSA. Empirical treatment can be based upon the antibiotic susceptibility pattern of organisms circulating within the facility. Cultures should be obtained even during outbreaks. Cultures should also be obtained if a patient fails to respond to treatment. The infection control officer or the infection control committee should review patient records for appropriateness of diagnosis and treatment.

Treatment

The indiscriminate use of antibiotics can lead to increased drug resistance and should be discouraged. In many cases, drainage and appropriate wound care will suffice. If used, antibiotics should be selected that are known to be effective against MRSA. Trimethoprim-sulfamethoxazole (Bactrim, Septra) in a dose of one double-strength tablet twice daily is usually effective in patients who have MRSA. Some clinicians also add rifampin in a dose of 600 mg once daily. Due to the rapid development of resistance, rifampin should not usually be used alone to treat infections due to SA. For more serious infections, vancomycin, linezolid, daptomycin, and quinupristin-dalfopristin may be used.

Vancomycin has been used for many years for the treatment of SA and MRSA. Concerns about vancomycin include hypersensitivity reactions, a histamine release syndrome (red man syndrome) related to rapid infusion, lack of availability of an oral formulation for the treatment of systemic infection, concerns about the development of vancomycin resistant enterococcus, and concerns about the emergence of vancomycin resistant staphylococcus aureus (VRSA) and strains with reduced sensitivity to vancomycin (VISA).

Eradication of Carriage

SA and MRSA are commonly found in the anterior nares of otherwise healthy asymptomatic individuals. Routine eradication of this carriage is neither efficacious nor recommended. In some cases of recurrent active disease, clearance of the organism from the nose can be beneficial. Mupirocin calcium 2% ointment (Bactroban) applied to both anterior nares bid for 5-7 days, is commonly used for this purpose.

Infection Control Measures

Once CA-MRSA infections are identified, personnel at all levels and in all disciplines in the facility need to be informed and to participate in control measures. Factors that may have contributed to outbreaks of MRSA in jails and prisons in the U.S. include poor hygiene, restricted access to medical care, uninformed medical staff, and failure to diagnose MRSA infections because of infrequent culture collection. Risk factors for MRSA that have been identified in jails and prisons have included skin lacerations, prolonged incarceration, previous antimicrobial use, self-draining of boils, performing one's own dressing changes, washing clothes by hand, sharing clothing or linen, and sharing soap.

Hygiene can be improved by patient education, improving access to soap and bathing, maintaining an adequate supply of dressing materials, and following appropriate laundry procedures. Materials coming into the laundry may be contaminated with CA-MRSA. Laundry workers must be provided with protective equipment and instructed regarding its use. CA-MRSA has the potential to produce toxins and cause food-poisoning, so special care should be exercised in carrying on "routine" daily review of workers for infections at the time of an outbreak. Access to medical care can be improved by eliminating co-payment requirement for contagious conditions, maintaining sufficient clinical staff to ensure prompt access to care, and establishing 24/7 urgent care for serious medical conditions. All correctional employees should be educated about the importance of prompt evaluation and treatment of infectious conditions. Furthermore, clinicians should be reminded to culture all skin and soft tissue infections and to not attribute skin lesions to insect bites.

CA-MRSA survives well on particularly warm, moist surfaces. Proper cleaning techniques, which should be reviewed with team supervisors, reduce the bacterial load, especially when antimicrobial cleaning agents (most often those containing quaternary ammonium compounds) are used. Facilities with CA-MRSA outbreaks should establish cleaning schedules and log their cleaning activities as part of their overall facility quality improvement activities.

A physical review of all units can therefore be very helpful in reducing opportunities for bacterial transfer. Surfaces that become easily contaminated require special attention, such as toilet seats, sinks, bathtubs, weight room equipment, etc. that are often in direct contact with skin. Frequent use of antimicrobial products can leave a residual film that can reduce the surface load of bacteria over an extended period of time. Hand washing is the most effective way to reduce transmission of CA-MRSA. The practice of leaving a towel next to a sink should be avoided, as shared towels provide perhaps the best transfer medium of all for CA-MRSA. Paper towels should be used instead.

Terminal disinfection should be employed in housing areas and is especially important during CA-MRSA outbreaks. Materials that cannot be sanitized should be discarded. Except for patients with secretions that cannot be controlled and are likely to contaminate the environment (including prisoners who intentionally spread contamination), no special separate housing is necessary.

If inmates understand how CA-MRSA is transmitted, they are more likely to practice good hygiene and protect themselves from transmission. Inmates should be educated about personal hygiene and advised to avoid touching other individuals' wounds or wound drainage. Inmates should be provided regular access to soap, showers, and sinks. Clinical staff should follow standard precautions while providing wound care. Infection control measures can never be overemphasized; even in the hospital setting many healthcare professionals neglect hand washing. In an effort to improve hand hygiene, the use of alcohol-containing antiseptic scrubs is increasingly being encouraged. However, security concerns may lead to these particular disinfectants not being universally embraced in the correctional setting. During outbreaks prisoners need to be encouraged to present possible CA-MRSA lesions to health services personnel for examination. Barriers to health care should be reviewed and lowered or eliminated during outbreaks. For example, during a CA-MRSA outbreak a facility could waive co-payment for evaluation of skin problems.

Conclusion

An aggressive approach to the management of MRSA can be effective. In Indiana, one moderately large facility was reporting approximately 40 cases of CA-MRSA per month when basic outbreak measures were implemented; within six weeks the outbreak was terminated. In another facility, a maximum-security setting, an alert physician noted an association between infections and new tattoos. The facility was briefly locked down and searched. With confiscation of the contaminated tattoo works, the outbreak was terminated. A particularly severe outbreak occurred in one Indiana jail. It was discovered that inmates were self-inoculating in order to get a ride out of the facility to a hospital. The high-load inoculation resulted in very aggressive infections and one prisoner nearly died. In other correctional settings, intensive efforts to control MRSA have not been as effective.

The involvement of experts in infection control and infectious diseases can be useful in both managing individual patients and establishing protocols specific to the unique needs of each facility. Correctional facilities experiencing outbreaks of MRSA should seek assistance from their local and state health departments. MRSA outbreaks can be reported to CDC (TEL: 800-893-0485) through state departments of corrections and state health departments. Preventing MRSA disease in inmates might be an important measure for preventing MRSA in the community outside the correctional facility.

Dean Rieger, M.D., M.P.H., is Medical Director at Indiana Department of Corrections. He has nothing to disclose.

Joseph Bick, M.D., is Chief Medical Officer at California Medical Facility. He has nothing to disclose.