Journal Review: As much as one-fifth of MRSA occurs in community
(Editor’s note: Methicillin-resistant Staphylococcus aureus is arising independently in American communities with striking speed. This month, we feature three recent reports documenting the emergence of community-acquired MRSA.)
As much as one-fifth of MRSA occurs in community
Nearly a quarter of patients hospitalized
Fridkin SK, Hageman JC, Morrison M, et al. Methicillin-resistant Staphylococcus aureus disease in three communities. N Engl J Med 2005; 352:1,436-1,444.
A surprising 8% to 20% of all methicillin-resistant Staphylococcus aureus isolates collected as part of a prospective population-based surveillance were not associated with traditional risk factors and were classified as community-associated MRSA, the authors report.
Most of the isolates were associated with clinically relevant infections that required treatment. The most common infections involved skin and soft tissues; however, 6% were considered invasive. Attributable mortality was low, but 23% of patients were hospitalized for these infections.
"The choice of appropriate antimicrobial agents for suspected S. aureus infections of skin and soft tissue in patients in the community must now take into account the emergence of community-associated MRSA," the authors report. Providers should be aware that several available antimicrobial agents should be effective in treating these infections.
They evaluated MRSA infections in patients identified from population-based surveillance in Baltimore and Atlanta and from hospital-laboratory-based sentinel surveillance of 12 hospitals in Minnesota. Information was obtained by interviewing patients and by reviewing their medical records. Infections were classified as community-acquired MRSA disease if no established risk factors were identified. From 2001 through 2002, 1,647 cases of community-acquired MRSA infection were reported, representing between 8% and 20% of all MRSA isolates.
The annual disease incidence varied according to site (25.7 cases per 100,000 population in Atlanta vs. 18.0 per 100,000 in Baltimore) and was significantly higher among persons less than two years old than among those who were two years of age or older, and higher among blacks than among whites in Atlanta. Six percent of cases were invasive, and 77% involved skin and soft tissue. The infecting strain of MRSA was often (73%) resistant to prescribed antimicrobial agents. Among patients with skin or soft-tissue infections, therapy to which the infecting strain was resistant did not appear to be associated with adverse patient-reported outcomes.
"Community-associated MRSA infections are now a common and serious problem," the authors concluded. "These infections usually involve the skin, especially among children, and hospitalization is common."
To avoid clinical complications from community-acquired MRSA infections, clinicians should now consider MRSA as a potential pathogen in patients with suspected S. aureus infections in the community setting. Clinicians should obtain appropriate material for bacterial culture. They should follow up on the results of susceptibility testing of all S. aureus isolates and recommend surgical drainage of infections when feasible.