ANTIBIOTIC SUSCEPTIBILITY PATTERNS AND PLASMID PROFILES OF PENICILLINASE-PRODUCING NEISSERIA-GONORRHOEAE STRAINS IN DURBAN, SOUTH-AFRICA, 1990-1993

Background and Objectives: The appearance of strains of Neisseria gono rrhoeae resistant, both chromosomally and plasmid-mediated, to penicil lin and other antibiotics makes this versatile pathogen difficult to t reat, There is, therefore, a need for surveillance of N. gonorrhoeae s trains to determine the efficacy of current therapeutic measures, Goal s: To survey the antibiotic susceptibilities and plasmid profiles of p enicillinase-producing N. gonorrhoeae strains isolated over a 4-year p eriod, Study Design: Penicillinase-producing N. gonorrhoeae strains we re detected by the chromogenic cephalosporin test, Minimum inhibitory concentrations to penicillin G, tetracycline, ceftriaxone, and ciprofl oxacin were determined using the E-test. Plasmid DNA was obtained by t he alkaline lysis method and profiles generated, Results: Penicillinas e-producing N. gonorrhoeae strains increased from 16.4% to 19.0% in th e period from 1990 through 1993, Although all strains were resistant t o penicillin, strains were susceptible to varying levels of ciprofloxa cin, ceftriaxone, and even tetracycline, All penicillinase-producing N . gonorrhoeae strains possessed, the 2.6-megadalton cryptic plasmid, a nd in addition 87.7% contained the 24.5-megadalton conjugative plasmid , Of the six known gonococcal beta-lactamase plasmids, the 4.4-megadal ton Asian and 3.2-megadalton African plasmids were predominant, The mo st prevalent plasmid profile contained the 2.6-megadalton cryptic, 24. 5-megadalton conjugative, and 4.4-megadalton Asian plasmids, Conclusio ns: To ensure effective treatment of gonorrhea, continued surveillance of the antimicrobial susceptibilities and plasmid profiles of penicil linase-producing N. gonorrhoeae strains is necessary.