Prevalence and persistence of Neisseria cinerea and other Neisseria spp. in adults.

Neisseria cinerea is a commensal Neisseria sp. which was first described in 1906 but was subsequently misclassified as a subtype of Branhamella catarrhalis. N. cinerea resembles Neisseria gonorrhoeae in both cultural and biochemical characteristics and, thus, may also have been misidentified as N. gonorrhoeae. Of 202 patients whose oropharynges were colonized by Neisseria spp., N. cinerea was isolated in 57 (28.2%) patients, including 25 (30.1%) of 83 women, 22 (23.9%) of 92 heterosexual men, and 10 (37.0%) of 27 homosexual men in Seattle, Wash., in 1983 to 1984. N. cinerea was isolated from the urethra of only one (1.1%) patient. The oropharynges of many individuals were colonized persistently by strains of N. cinerea and other Neisseria spp.