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