Genotypes and phenotypes of beta lactamase producing strains of Neisseria gonorrhoeae from African countries.

The phenotypes and genotypes of 26 beta lactamase (penicillinase) producing strains of Neisseria gonorrhoeae (PPNG) from African countries were investigated. Using the restriction enzyme technique nine different restriction enzyme patterns were found, two of them in 15 strains. Of the 26 strains, 16 belonged to serogroup WI (containing protein type IA) and 10 to serogroup WII/III (containing protein IB). Among the IA strains four different serovars were represented, whereas six serovars were found among the IB strains. Five different auxotypes were identified, of which proline requiring (found in 12 strains) and prototrophic (found in 10 strains) dominated. Twelve strains harboured a 4.4 megadalton as well as a 24.5 megadalton plasmid. A 3.2 megadalton plasmid was found in 14 strains, one of which also harboured a 24.5 megadalton plasmid. The 2.8 megadalton cryptic plasmid was present in all 26 strains. The MICs of doxycycline ranged from 0.25 to 2.0 mg/l; the MIC 50% for WI strains was 0.25 mg/l and for WII/WIII strains 1.0 mg/l. A total of 10 different combinations of restriction enzyme pattern, serovar, auxotype, and plasmid were seen in the 16 WI strains compared with eight such combinations in the 10 WII/WIII strains. As expected, the restriction enzyme technique and serological classification gave better differentiation than plasmid profiles and susceptibility to doxycycline. More relevantly, however, these techniques also compared favourably with auxotyping. When the different systems were combined, the sensitivity was greatly increased.