Microbiology
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.
Syndromes
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 organism 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.
Treatment
They always make beta-lactamases.
Third-generation cephalosporin OR quinolone OR tetracycline OR amoxicillin/clavulanate OR trimethoprim/sulfamethoxazole or azithromycin or clarithromycin or second-generation cephalosporin.
Notes
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