Aspiration pneumonia, anaerobic infections, and lung abscess.

Anaerobic pleuropulmonary infections are common in the setting of aspiration. Treatment is with penicillin or in mixed infections, penicillin and other appropriate antimicrobial agents. Four syndromes are commonly recognized. Simple pneumonitis resolves promptly with antibiotic therapy. If treatment is delayed, simple pneumonitis may evolve into a more fulminant process of necrotizing pneumonia with a significant mortality despite antibiotic therapy. Lung abscess, typically a subacute or chronic infection, responds well to antibiotic therapy so long as the cavity is drained via the communicating bronchus. Empyema requires surgical drainage by either closed or open thoracostomy if resolution is to be achieved.