Branhamella catarrhalis has been recovered from various sites of infection in the respiratory tract. These include chronic otitis media, tonsillitis, adenoiditis and pneumonia. This organism was recovered in many of these infections mixed with other aerobic, facultative anaerobic and anaerobic bacteria. Increasing numbers of isolates of this organism have been noted to produce beta-lactamase. This may contribute to the high failure rate of penicillins in eradicating polymicrobial respiratory infections.