Neisseria meningitidis
Neisseria meningitidis, often referred to as the meningococcus, is a Gram-negative bacterium that can cause meningitis and other forms of meningococcal disease such as meningococcemia, a life-threatening sepsis. The bacterium is referred to as a coccus because it is round, and more specifically a diplococcus because of its tendency to form pairs.
| Neisseria meningitidis | |
|---|---|
| Scanning electron micrograph of a single N. meningitidis cell (colorized in blue) with its adhesive pili (colorized in yellow). The scale bar corresponds to 1 µm. | |
| Scientific classification | |
| Domain: | Bacteria |
| Phylum: | Pseudomonadota |
| Class: | Betaproteobacteria |
| Order: | Neisseriales |
| Family: | Neisseriaceae |
| Genus: | Neisseria |
| Species: | N. meningitidis |
| Binomial name | |
| Neisseria meningitidis Albrecht & Ghon 1901 | |
About 10% of adults are carriers of the bacteria in their nasopharynx. As an exclusively human pathogen, it is the main cause of bacterial meningitis in children and young adults, causing developmental impairment and death in about 10% of cases. It causes the only form of bacterial meningitis known to occur epidemically, mainly in Africa and Asia. It occurs worldwide in both epidemic and endemic form.
N. meningitidis is spread through saliva and respiratory secretions during coughing, sneezing, kissing, chewing on toys and through sharing a source of fresh water. It has also been reported to be transmitted through oral sex and cause urethritis in men. It infects its host cells by sticking to them with long thin extensions called pili and the surface-exposed proteins Opa and Opc and has several virulence factors.