Neisseria

Neisseria is a large genus of bacteria that colonize the mucosal surfaces of many animals. Of the 11 species that colonize humans, only two are pathogens, N. meningitidis and N. gonorrhoeae. Most gonoccocal infections are asymptomatic and self-resolving, and epidemic strains of the meningococcus may be carried in >95% of a population where systemic disease occurs at <1% prevalence. Neisseria species are Gram-negative bacteria included among the proteobacteria, a large group of Gram-negative forms. Neisseria diplococci resemble coffee beans when viewed microscopically. The genus Neisseria is named after the German bacteriologist Albert Neisser, who in 1879 discovered its first example, Neisseria gonorrheae, the pathogen which causes the human disease gonorrhea. Neisser also codiscovered the pathogen that causes leprosy, Mycobacterium leprae. These discoveries were made possible by the development of new staining techniques which he helped to develop.