Encapsulated gram negative diplococci.
Normal flora. Humans are the reservoir.
Quadrivalent vaccine prevents disease by serogroups A/C/W-135/Y.
Occurs in outbreaks particularly in crowded settings.
Colonizer and cause of invasive disease:
Generally of little significance when cultured from nonsterile sites e.g. genital, pharynx.
Prophylaxis may be required for close contacts and healthcare workers.