Branhamella catarrhalis infections.

Branhamella (Moraxella) catarrhalis is responsible for a significant number of bronchopulmonary infections in adults, as well as otitis media and sinusitis in children. This gram-negative diplococcus is indistinguishable from Neisseria gonorrhoeae on gram-stained smear. Many strains of the organism produce beta-lactamase and are resistant to the penicillins and other beta-lactam antibiotics. When B. catarrhalis is the probable pathogen, a beta-lactamase-resistant antibiotic is the initial drug of choice in both adults and children.