Characterisation by plasmid profiles, serogroups, and auxotypes of Neisseria gonorrhoeae from Harare, Zimbabwe

One hundred and fifty five strains of Neisseria gonorrhoeae were regrown from 216 freeze dried cultures originally isolated in Zimbabwe. The gonococci were from men (61 strains) and women (39 strains) attending a referral sexually transmitted diseases (STD) clinic, from women presenting for delivery at hospital with signs of sepsis (22 strains) or with an asymptomatic infection (16 strains), and from babies with ophthalmia neonatorum (17 strains). Seventy five of the 100 isolates from STD clinic patients and 29 of the 55 isolates from hospital patients were penicillinase producing N gonorrhoeae (PPNG). Two thirds of all PPNG strains contained the 24.5 megadalton conjugative plasmid. The 3.2 megadalton resistance plasmid, usually associated with PPNG strains originating in Africa, was present in only one third of the PPNG strains. The 2.6 megadalton cryptic plasmid was present in all strains. Prototrophic and proline requiring auxotypes predominated in both PPNG and non-PPNG strains. Arginine requiring auxotypes were found in four of the 16 isolates from asymptomatic women, whereas three of the 22 strains from women with puerperal sepsis and four of the 61 strains from men with urethritis required both proline and arginine. Fifty eight out of 66 PPNG strains with the 4.4 megadalton plasmid required proline compared with 22/38 PPNG strains with the 3.2 megadalton plasmid and 20 ofthe 51 non-PPNG strains. Three quarters (38/51) of non-PPNG strains belonged to serogroup WII/III as did 42/66 PPNG strains with the 4.4 megadalton plasmid but only 10/38 PPNG strains with the 3.2 megadalton plasmid. In all, 23 different strain types could be recognised on the basis of plasmid content, auxotype, and serogroup. There was, however, a high degree of homogeneity between PPNG and non-PPNG isolates.