Pathogenicity of Branhamella catarrhalis.

Branhamella catarrhalis--a Gram-negative diplococcus--differs biochemically from other Neisseriaceae and possesses a specific protein with antigenic properties. Although scattered cases of meningitis and endocarditis have been reported since 1907, B. catarrhalis has been considered a non-pathogenic, pharyngeal commensal. However, relatively recent reports have shown B. catarrhalis to play a significant role in the etiology of otitis media and bronchopulmonary infections. Some reports also indicate a pathogenic role in sinusitis and longstanding cough in children, and in acute laryngitis in adults. B. catarrhalis is susceptible to co-trimoxazole, erythromycin, cephalosporins and tetracyclines. Most strains are also susceptible to penicillin, but the frequency of beta-lactamase producing B. catarrhalis has increased from 4% to 25% during the last six years (Sweden). First choice antibiotics in infections with penicillin-resistant strains would be erythromycin and co-trimoxazole.