Viridans streptococcal pulmonary parenchymal infections.

Pulmonary parenchymal infections were caused by viridans streptococci in two patients. Pleural empyema and lung abscess occurred in a previously healthy adult; an uncomplicated pneumonia developed in an immunocompromised host. In the first case, the diagnosis was ascertained by percutaneous lung abscess aspiration, transtracheal aspiration, and thoracentesis culture findings. In the second case, the diagnosis was established by transtracheal aspiration culture results.