Pharyngeal colonisation by Neisseria gonorrhoeae and Neisseria meningitidis in black and white patients attending a venereal disease clinic.

Pharyngeal colonisation by Neisseria gonorrhoeae and Neisseria meningitidis was studies in 2000 patients attending a venereal disease clinic. Of these patients, 64% were white and 36% were black. The incidence of gonococcal infections was highest in the period from June to August. The incidence of genital or rectal infections or both was higher in the black patients. Pharyngeal colonisation by gonococci was present in 1.3% of the patients. There was no significant associations between pharyngeal colonisation and the pharyngeal symptoms, race, sex, or marital state of the patients. Pharyngeal colonisation was more frequent in patients with gonococcal infections at other sites. However, in 40.7% of the patients with pharyngeal colonisation, the pharynx was the only culture-positive site. There was no significant difference in the auxotypes or in the antibiotic susceptibility of the pharyngeal and the rectal-genital isolates except in the susceptibility to spectinomycin. Our findings do not indicate that gonococci isolated from the pharynx differ significantly from gonococci isolated from rectal or genital sites. It was notable that meningococcal colonisation of the pharynx was significantly more frequent in the white patients. This may be a genetically determined phenomenon.