Session: Poster Session: Community-MRSA in Hospitals Worldwide
Tuesday, October 28, 2008: 12:00 AM
Room: Hall C
Background: Methicillin-resistant Staphylococcus aureus (S. aureus [SA]) (MRSA) pneumonia is a major cause of hospital-acquired pneumonia in the US. The importance of MRSA in community-acquired pneumonia (CAP) remains unclear, however. We address this issue in this study. Methods: We retrospectively identified all patients with SA CAP admitted to a large US urban teaching hospital between January 2005 and December 2007. Patients were identified based on a discharge diagnosis of pneumonia and (within 48h of admission): (1) positive SA culture (blood or sputum); (2) positive chest X-ray; and (3) signs/symptoms of pneumonia. Patients with healthcare-associated pneumonia (HCAP) were excluded, using established criteria (eg, recent hospitalization, hemodialysis). Patients were designated as having MRSA or methicillin-susceptible SA (MSSA) based on initial culture. Initial (ie, empiric) antibiotic therapy was designated as appropriate vs inappropriate based on whether it provided coverage for MRSA or MSSA, as appropriate. Results: A total of 116 patients with SA CAP were identified. Mean (SD) age was 60 (17) years; 85 patients (73%) were nonwhite. Prevalence of comorbidities (eg, diabetes, heart disease, chronic respiratory disease) was high (>20%). Fifty-two patients (45%) had positive MRSA cultures; USA-300 accounted for 42% of MRSA strains. Only 9 MRSA patients (17%) had vancomycin MIC values <1 mcg/ml by E-test. Patients with MRSA were more likely to be male (71% vs 47% for MSSA; p=.014); no other differences were noted. Initial antibiotic therapy was more often inappropriate in patients with MRSA (23 [44%] vs 12 [19%] for MSSA; p=.004). Conclusion: MRSA is a common finding in patients with SA CAP; almost one-half of these patients receive initial antibiotic therapy that is inappropriate.