Interrelationships of viral, mycoplasmal, and bacterial agents in uncomplicated pneumonia.

Minor viral respiratory infections have long been thought to play a role in the pathogenesis of bacterial pneumonia. Heffron (1) noted that the major evidence supporting this concept was supplied by the many studies in which a large proportion of patients reported symptoms of upper respiratory infection during the period preceding the onset of pneumonia. He concluded his consideration of this issue, however, with the statement that it was not clear that a virus infection is an essential prerequisite for the development of pneumonia in every instance or indeed possibly in any instance. Wood (2), on the other hand, stressed the importance of viral upper respiratory tract infections and the aspiration of infected secretions in the pathogenesis of pneumococcal pneumonia. Influenza is generally held to predispose to pulmonary bacterial infections, particularly with Diplococcus pneumoniae and Staphylococcus aureus (3). Rubeola is also known to be associated