Phenotypic and genotypic characterization of penicillinase-producing strains of Neisseria gonorrhoeae.

Thirty penicillinase-producing Neisseria gonorrhoeae (PPNG) strains, 26 representing 9 serovars of the protein IB and 4 representing 2 serovars of the protein IA serogroup, had 10 different patterns when investigated by the restriction enzyme (RE) technique with Hind III enzyme. One RE pattern dominated, representing 11 strains with 6 different serovars of both the protein IA and IB serogroup. Identical serovars and RE patterns were found among 7 patients (3, 2 and 2, respectively) with positive epidemiology. The majority of the strains (24/30) were resistant to, or showed decreased sensitivity to, doxycycline with minimum inhibitory concentrations between 1 and 8 mg/l, consistent with the Far East origin. All the 30 PPNG strains showed by agarose gel electrophoresis to harbour a 2.8 Mdalton, a 4.4 Mdalton, as well as a 24.5 Mdalton plasmid, whereas the two non-PPNG strains had only the 2.8 Mdalton plasmid.