Branhamella Catarrhalis Respiratory Infections

Branhamella catarrhalis, a normal commensal of the oropharynx, is increasingly recognized as an important cause of bronchitis and bacterial pneumonia. Six patients with B. catarrhalis pneumonia documented by transtracheal aspirate or blood culture were studied, and 429 previously reported cases of B. catarrhalis bronchitis and pneumonia were reviewed. The mean age of patients with B. catarrhalis infection was 64.8 years, and preexisting chronic obstructive pulmonary disease was common. The typical clinical picture was that of purulent tracheobronchitis; patients with pneumonia were not severely ill and differed from those with bronchitis mainly by the presence of patchy lower-lobe infiltrates on chest roentgenogram. Fifty-three percent of reported strains produced beta-lactamase. Thirty-nine percent of the cultures were mixed, predominantly with Haemophilus influenzae and Streptococcus pneumoniae. The microbiologic, immunologic, and clinical features of B. catarrhalis infection, as well as the antimicrobial susceptibilities of this organism, were reviewed. The reasons for the lack of recognition of this common pathogen and possible solutions were considered.