Methicillin-resistant Staphylococcus aureus: a new community-acquired pathogen?

PURPOSE OF REVIEW: The main goal of this review is to describe the emergence of methicillin-resistant Staphylococcus aureus (MRSA) as a community pathogen. RECENT
FINDINGS: Community-acquired MRSA has emerged as an important infection in the community setting. It has primarily been associated with skin and soft-tissue infections, but can also cause severe pulmonary infections, including pneumonia and empyema. Community-acquired MRSA is typically more susceptible to a wider class of antibiotics than healthcare-associated MRSA. Community-acquired MRSA is also more virulent compared with healthcare-associated MRSA isolates. Community-acquired MRSA usually contains the gene encoding Panton-Valentive leukocidin, which is a toxin that creates lytic pores in the cell membranes of neutrophils and induces the release of neutrophil chemotactic factors that promote inflammation and tissue destruction. The optimal antibiotic treatment for Panton-Valentive leukocidin-positive community-acquired MRSA is unknown; however, antibiotics with activity against MRSA and the ability to inhibit toxin production may be optimal (linezolid or clindamycin for susceptible isolates).
SUMMARY: Clinicians should be aware of the emergence of community-acquired MRSA as an important cause of serious infections arising in the community setting. Appropriate antibiotic therapy should be initiated as soon as infection with this pathogen is suspected.