Clinical and economic outcomes in patients with community-acquired Staphylococcus aureus pneumonia

While the clinical and economic consequences of S. aureus pneumonia in healthcare settings have been well documented, much less is known about community-acquired S. aureus pneumonia (CAP).

We retrospectively identified all patients admitted to a large US urban teaching hospital between January 2005 and May 2008 with pneumonia and positive blood or respiratory cultures for S. aureus within 48 hours of admission. Patients with suspected healthcare-associated pneumonia (HCAP) were excluded from the study sample, using established criteria (eg, recent hospitalization, admission from nursing home, hemodialysis). Patients were designated as having methicillin-resistant (MRSA) or methicillin-susceptible (MSSA) CAP based on initial S. aureus isolates. Initial therapy was designated "appropriate" vs. "inappropriate" based on expected susceptibility of the organism to the regimen received.

We identified a total of 128 CAP patients with S. aureus isolates; mean (standard deviation [SD]) age was 60 (17) years. A total of 55 patients (43%) had initial cultures positive for MRSA. Patients with MRSA CAP were more likely to receive inappropriate initial therapy (24 [44%] vs. 13 [18%] for MSSA; P = 0.002). Approximately 25% of all patients underwent surgery for pneumonia, 69% received mechanical ventilation, 79% were admitted to intensive care unit (ICU), and 24% died in hospital. Mean (SD) length of stay was 17.0 (15.7) days, and total hospital charges averaged $127,922 ($154,605) per patient; there were no significant differences between patients with MRSA vs. MSSA CAP.

Outcomes are poor, hospital stays are long, and costs of care are high in patients with S. aureus CAP, and do not differ between those with MRSA vs. MSSA.