Introduction to Neisseriaceae
All pathogenic aerobic gram-negative cocci belong to the Neisseriaceae family, which is composed of 5 genera:
Of these, Neisseria includes the most important human pathogens:
Numerous saprophytic Neisseriaceae commonly inhabit the oropharynx, vagina, or colon but rarely cause human disease.
Moraxella catarrhalis causes otitis media in children, sinusitis in people of all ages, and exacerbations of COPD, sometimes community-acquired pneumonia in adults, and infrequently bacteremia. Over half a dozen other Moraxella sp and the related Kingella kingae cause infections in the CNS, respiratory tract, urinary tract, endocardium, bones, and joints.
Humans are the only reservoir of Neisseria, and person-to-person spread is the prime mode of transmission. Both N. meningitidis (meningococcus) and N. gonorrhoeae (which causes gonorrhea), can exist in an asymptomatic carrier state. Carrier states are particularly important with meningococcus because of its association with epidemics.