Characteristics of Drug-Susceptible and Drug-Resistant Staphylococcus aureus Pneumonia in Patients with HIV.

Objectives: To examine predictors and outcomes of Staphylococcus aureus Pneumonia (SAP) in people with HIV compared with Streptococcus pneumoniae Pneumonia (SPP), and to compare Methicillin-Resistant S. aureus (MRSA) with Methicillin-Sensitive S. aureus (MSSA) pneumonias in this population.

Methods: We conducted a retrospective case-control study of HIV-infected patients admitted to a single center with culture-proven S. aureus or S. pneumoniae pneumonia. We identified patients through a computerized database, conducted structured chart reviews, and performed bivariate and multivariate analyses using logistic regression.

Results: We compared 47 SAP episodes in 42 patients with 100 SPP episodes in 93 patients. Use of any antibiotics prior to admission (OR=3.5, p=0.02), a co-morbid illness (OR=4.2, p=0.04), and recent healthcare contact (OR=12.0, p<0.001) were significant independent predictors of SAP. Patients with SAP were more likely to require intensive care (OR=2.7, p=0.02) and mechanical ventilation (OR=3.1, p=0.02), but not to die. MRSA was more common (57% of cases) than MSSA, but outcomes were not significantly worse.

Conclusions: Patients with HIV and SAP have worse outcomes than those with SPP. Clinicians should consider empiric antibiotic coverage for MRSA in patients admitted with HIV and pneumonia, given the high prevalence of MRSA. Further studies are warranted to examine morbidity differences between HIV-associated MSSA and MRSA pneumonia.