Streptococcus zooepidemicus (group C) pneumonia in a human.

Lancefield group C streptococcal pneumonia appeared in a previously healthy young adult. The patient apparently acquired the infection while caring for her sick horse, and experienced a gradual onset of the illness. There was rapid accumulation of pleural fluid and empyema requiring open drainage. Group C pneumonia cannot be distinguished from classic group A pneumonia on clinical grounds. Beta-hemolytic streptococci isolated from sputum, transtracheal aspirates, pleural fluid, or blood of patients with pneumonia should be grouped by the precipitin method of Lancefield or one of its more rapid modifications.