Infectious Disease Compendium



gram-negative diplococcus. M. atlantae, M. catarrhalis, M. lacunata, M. nonliquefaciens, M. osloensis, M. phenylpyruvica and others. (PubMed Review)

Epidemiologic Risks

Part of life. More often found in children, only 1-3% of adults will be carriers.


M. catarrhalis: Otitis (20%) (PubMed), sinusitis, URI, exacerbation of COPD (second cause), occasionally pneumonia in patients with COPD. Non catarrhalis spp. only rarely cause infections.

Most common organsim isolated in laryngitis in adults.

Moraxella lacunata: blepharoconjunctivitis in humans.

Moraxella bovis: keratoconjunctivitis in swine. Look out for the pig with the red eyes. It hasn't been crying.


They always make beta-lactamases.

Third generation cephalosporin OR quinolone OR tetracycline OR amoxicillin/clavulanate OR trimethoprim/sulfamethoxisole or azithromycin or clarithromycin or second generation cephalosporin.


The big problem with this organism is 80-90% now make a beta lactamase; probably isn't important in COPD exacerbation; probably is important in pneumonia.

Osler died of this organism, or so I have read.

Last update: 05/05/18