Nosocomial pneumonia in adult general medical and surgical patients at Christchurch Hospital

Aims. To determine the incidence, microbial cause, and outcome of nosocomia l pneumonia in adult general medical and surgical patients at Christchurch Hospital. Methods. A one-year prospective study of consecutive patients developing no socomial pneumonia in a university-affiliated hospital. Expanded diagnostic laboratory testing was undertaken to identify the microbial cause of pneum onia. Results. We recruited 126 patients, which represented an incidence of 6.1 p er 1000 admissions. Only 52 (41%) patients submitted sputum that satisfied the cytological screening criteria for testing. A microbial cause was ident ified in 47 cases (37%): the most common was Legionella spp. (sixteen cases ), followed by Influenza A (six cases) and Staphylococcus aureus (four case s). We did not identify an environmental source of the Legionella species. Fourteen patients (11%) died as a consequence of pneumonia and nearly all o f these had significant comorbidity. Renal impairment, alcohol excess, and severity of pneumonia were the most powerful predictors of a fatal outcome by univariate analysis. Conclusions. In most patients we did not identify a microbial cause of pneu monia; when we did, Legionella species were the most common, although this micro-organism has a long incubation period so some subjects may have acqui red it before admission. These results guide preventative efforts, diagnost ic testing and selection of: antimicrobial therapy for nosocomial pneumonia in our hospital.