Isolation of respiratory syncytial and influenza viruses from the sputum of patients hospitalized with pneumonia.

Routinely collected sputum specimens from 100 adults hospitalized with pneumonia were frozen at -70 C until inoculation into Madin-Darby canine kidney, fetal tonsil, and esophageal epithelial cells. Six influenza A (H3N2) viruses, two respiratory syncytial viruses, three rhinoviruses, and nine herpes simplex viruses were recovered. Four patients with influenza virus and one with respiratory syncytial virus isolated had nosocomial pneumonia. Viral isolation from sputum specimens may aid the diagnosis of pneumonia of unclear etiology and merits further evaluation as a diagnostic tool and as an adjunct to influenza surveillance.