Community-acquired bacterial pneumonia requiring admission to hospital

Patients who develop bacterial pneumonia in the community often require admission to acute-care hospitals. Knowledge of the incidence of pneumonia due to different pathogens that are brought into an institution from the community may play a role in determining the patterns of infecting organisms responsible for hospital-acquired pneumonia. For 1 year, we prospectively reviewed the records of patients admitted to our 1000-bed community hospital with community-acquired bacterial pneumonia (CABP). Patients had clinical signs and symptoms, positive radiologic findings, and pure cultures of potential pathogens from sputum, blood, pleural fluid, lung aspirate, lung biopsy, or transtracheal aspirate. Pneumonia due to Legionella pneumophila was diagnosed by serum indirect fluorescent antibody (IFA) titer greater than or equal to 1:256 and clinical signs and symptoms along with response to erythromycin. Of 204 patients with bacterial pneumonia, the following pathogens were implicated: Streptococcus pneumoniae, Haemophilus species, L. pneumophila, Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, oral anaerobic bacteria, Psuedomonas aeruginosa, Serratia marcescens, and others. Most patients were more than 50 years of age and many had evidence of underlying pulmonary disease. The etiology of CABP may not be as predictable as in the past. Empiric antimicrobial therapy for CABP should include agents with activity against the pathogens prevalent in the community.