[1] Species of this genus (family Neisseriaceae) of parasitic bacteria grow in pairs and occasionally fours, and thrive best at 98.6 °F (37 °C) in the animal body or serum media.

Some functions of the type IV pili include: mediating attachment to various cells and tissues, twitching motility, natural competence, microcolony formation, extensive intrastrain phase, and antigenic variation.

Neisseria bacteria have also been shown to be an important factor in the early stages of canine plaque development.

N. meningitidis has a polysaccharide capsule that surrounds the outer membrane of the bacterium and protects against soluble immune effector mechanisms within the serum.

Unlike most other Gram-negative bacteria, which possess lipopolysaccharide (LPS), both pathogenic and commensal species of Neisseria have a lipooligosaccharide (LOS) which consists of a core polysaccharide and lipid A.

It functions as an endotoxin, protects against antimicrobial peptides, and adheres to the asialoglycoprotein receptor on urethral epithelium.

N. weaveri (strain NCTC 13585) has the smallest known genome with only 2,060 encoded proteins[9] although N. meningitidis MC58 has been reported to have only 2049 genes.

[8] Diseases caused by N. meningitidis and N. gonorrhoeae are significant health problems worldwide, the control of which is largely dependent on the availability and widespread use of comprehensive meningococcal vaccines.

Development of neisserial vaccines has been challenging due to the nature of these organisms, in particular the heterogeneity, variability and/or poor immunogenicity of their outer surface components.

These authors proposed that the over-representation of DUS in DNA repair and recombination genes may reflect the benefit of maintaining the integrity of the DNA repair and recombination machinery by preferentially taking up genome maintenance genes that could replace their damaged counterparts in the recipient cell.