Methicillin-resistant Staphylococcus aureus or MRSA, are strains of bacteria that are resistant to penicillin and cephalosporin antibiotics. Before the 1990s, MRSA was a medical oddity. By the late 1990s, however, hospitals began to report the presence of MRSA more frequently. MRSA has also colonized some communities; however, these strains of resistant Staphylococcus aureus differ from those found in hospitals. The Centers for Diseases Control and Prevention reported in 2005 that more than 90,000 invasive MRSA infections occurred in the United States and more than 18,000 of these infections were associated with death. The CDC has provided the document, "Strategies for Clinical Management of MRSA in the Community" and, with the American Medical Association and Infectious Diseases Society of America, the CDC has published a MRSA treatment algorithm.
MRSA
Staphylococcus aureus is a common bacterium that frequently colonizes areas on the skin and nose. About 20 percent of people carry these bacteria without developing skin infections. It is not known, but is currently under study, what percentage of the population carries MRSA. Until recently, MRSA more often infected individuals that were immune compromised, but now MRSA-caused skin infections frequently affect young, healthy individuals and is a threat to the general public. The manifestations of MRSA infection are skin and soft tissue infections with the appearance of boils and abscesses. The severity of the infection ranges from mild to deep soft-tissue abscesses that require surgical removal. The CDC reports that rarely, MRSA has caused severe invasive infections, including necrotizing pneumonia, sepsis, musculoskeletal infections and necrotizing fasciitis.
Algorithm Summary
The first line of treatment for any skin infection is incision and drainage. The CDC recommends that a bacterial culture should be performed on the lesions if a patient has abscesses or purulent skin lesions, signs of systemic infection, or has a history of MRSA infection. The culture is used to determine whether the strain of Staphylococcus aureus is resistant to certain antibiotic treatments. The CDC reports that 90 percent of deep skin abscesses are successfully treated with incision and drainage alone. Penicillin or a cephalosporin antibiotic may be prescribed initially if the skin infection is greater than 5 cm in diameter or the person is immune compromised. The CDC recommends close patient follow-up and if the clinician determines the patient is not responding to conventional antibiotic treatment, the skin infection should be tested for antibiotic resistance and promptly treated with an antibiotic effective against MRSA.
Antibiotics
The CDC reports the drugs clindamycin, doxycycline, minocycline and linezolid are approved by the Food and Drug Administration for the treatment of skin infections caused by Staphylococcus aureus. The CDC also says that the fluoroquinolone antibiotics-ciprofloxacin and levofloxacin and the macrolides-erythromycin, clarithromycin, and azithromycine should not be used to treat MRSA skin infections because resistance is common or may rapidly develop.
Precautions
A potential complication of antibiotic treatment is clostridium difficile-associated disease, a severe gastrointestinal disorder. Some MRSA strains have already developed resistance to the available CDC-recommended antibiotics used to treat MRSA. The CDC further advocates more research on antibiotics to treat MRSA to establish optimal regimens for treatment and to define safety profiles.
Out-Patient Responsibility
The CDC recommends that patients with MRSA skin infections keep their wounds covered and dry, wash hands regularly and right after cleaning the wound, maintain good hygiene, do not share personal hygiene equipment, launder all clothing after each use, do not participate in activities that have skin-to-skin contact and clean surfaces that have skin contact with multiple individuals.
References
- Centers for Diseases Control and Prevention: Overview of Healthcare-Associated MRSA
- Centers for Diseases Control and Prevention: "Strategies for Clinical Management of MRSA in the Community"
- Centers for Diseases Control and Prevention: Outpatient Management of Skin and Soft Tissue Infections in the Era of Community-Associated MRSA
