Pneumonia is one of the leading causes of death in the United States. As health care has expanded into community settings, including outpatient clinics,
long-term care facilities, and dialysis centers, a new category of
pneumonia-health care-associated
pneumonia (HCAP)-has been defined. Bacterial resistance to
antibiotics is rising among
community-acquired infections, and the emergence of community-associated methicillin-resistant Staphylococcus aureus (MRSA)
infections, particularly the severe form of
necrotizing pneumonia mediated by USA 300 in young and healthy individuals, warrants attention. Although Streptococcus pneumoniae remains the most prevalent causative pathogen in community-acquired
pneumonia (CAP), S aureus
infections are increasingly being reported in community settings, especially in patients with HCAP. Recent surveillance of community-dwelling adults with
pneumonia admitted to United States hospitals has demonstrated a steady increase in S aureus isolates. Thus, MRSA should be considered in severe
pneumonia associated with
influenza-like symptoms, particularly when accompanied by
hemoptysis or
leukopenia. However, MRSA
pneumonia also can develop in the absence of preceding
influenza-like illness. Effective empiric
therapy for
pneumonia, whether CAP or HCAP, mandates selection of an agent with coverage against all likely pathogens. Failure to provide adequate initial antimicrobial coverage has been associated with an increased risk of death. The spread of resistant pathogens in the community challenges currently available
antimicrobial agents for effective treatment of MRSA-mediated
pneumonia. Approval of newer antimicrobials with MRSA activity may provide additional options for the management of
pneumonia. This article provides a review of the role of MRSA as a causative pathogen in CAP and HCAP.