Evidence for two distinct types of penicillinase-producing Neisseria gonorrhoeae

Since their recognition early in 1976, penicillinase (beta-lactamase)-producing Neisseria gonorrhoeae (P.P.N.G.) have been isolated in more than 15 countries. Most strains isolated in or epidemiologically linked with the Far East are relatively resistant to tetracycline in vitro, are phenotypically wild-type or proline-dependent auxotypes, and carry a plasmid with a molecular weight of 5800 000 (5-8 X 10(6)) daltons coding for beta-lactamase production. In contrast, P.P.N.G. epidemiologically linked with West Africa are more susceptible to tetracycline, require arginine for growth, and their gene coding for beta-lactamase synthesis is contained in a smaller 3-2 X 10(6) dalton plasmid. Moreover, 43% of the Far Eastern strains, but none of those from West Africa, have an additional 24-5 X 10(6) dalton conjugative plasmid which transfers the beta-lactamase R factor(s) to other gonococci. The presence of this conjugative plasmid may explain the relatively high prevalence of P.P.N.G. in certain areas of the Far East.