Branhamella catarrhalis, a respiratory tract pathogen.

Branhamella catarrhalis, formerly regarded as an oropharyngeal commensal, has more recently been implicated as an opportunistic pathogen in the respiratory tract. This report describes the isolation of B. catarrhalis from two consecutive samples of empyema fluid and also from sputum in thirteen cases of lower respiratory tract disease, where the isolate was considered to be etiologically significant. The antibiotic therapy required to treat such infections is discussed.