Moraxella catarrhalis is a gram-negative human mucosal pathogen that is morphologically similar to Neisseria spp. It is found as a common commensal of the nasopharynx and can cause upper respiratory tract infections. The infection presents as otitis media or sinusitis in children and the exacerbation of chronic bronchitis in adults with chronic obstructive pulmonary disease (COPD).
Moraxella catarrhalis is expected to be resistant to beta-lactam antibiotics including penicillin, ampicillin, amoxicillin, and piperacillin [ATC: J01CE01J01CA04J01CA01J01CA12].