The Neisseriaceae are a family of '' Pseudomonadota'', within the '' Neisseriales'' order of ''

Betaproteobacteria ''Betaproteobacteria'' are a class of Gram-negative bacteria, and one of the six classes of the phylum '' Pseudomonadota'' (synonym Proteobacteria). Metabolism The ''Betaproteobacteria'' comprise over 75 genera and 400 species. Together, they ...

''. While many organisms in the family are mammalian commensals or part of the normal

flora Flora (: floras or florae) is all the plant life present in a particular region or time, generally the naturally occurring (indigenous (ecology), indigenous) native plant, native plants. The corresponding term for animals is ''fauna'', and for f ...

, the genus '' Neisseria'' includes two important human pathogens, specifically those responsible for gonorrhea (caused by'' N. gonorrhoeae'') and many cases of

meningitis Meningitis is acute or chronic inflammation of the protective membranes covering the brain and spinal cord, collectively called the meninges. The most common symptoms are fever, intense headache, vomiting and neck stiffness and occasion ...

("meningococcal meningitis", caused by'' N. meningitidis''). As a group, the ''Neisseriaceae'' are strictly aerobic and

Gram-negative Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. Their defining characteristic is that their cell envelope consists ...

, occur mainly in pairs ( diplococci), and typically do not have

flagella A flagellum (; : flagella) (Latin for 'whip' or 'scourge') is a hair-like appendage that protrudes from certain plant and animal sperm cells, from fungal spores ( zoospores), and from a wide range of microorganisms to provide motility. Many pr ...

References

Bacteria of Medical Importance
in ''Todar's Online Textbook of Bacteriology''. * * {{Authority control Betaproteobacteria