Bacterial and fungal pneumonias.

Bacterial pneumonias occur with increased frequency and can be associated with increased morbidity in the HIV-infected population compared with normals. The pathogens that most frequently cause community-acquired pneumonias are S. pneumoniae, H. influenzae, and occasionally S. aureus. These pneumonias usually respond to appropriate antibiotic therapy; however, patients diagnosed with bacterial pneumonias are at increased risk for subsequent episodes. Nosocomial pneumonias, by contrast, are usually caused by gram-negative organisms and have a high mortality. Fungal pneumonias also have an increased incidence in AIDS patients, and usually occur in the setting of disseminated disease. Infections caused by C. neoformans, H. capsulatum, and C. immitis often recur despite a good initial response to amphotericin B. Maintenance therapy with an antifungal agent is therefore recommended.