Antimicrobial susceptibility of Neisseria gonorrhoeae isolated in Durban, South Africa.

One hundred and forty clinical isolates of Neisseria gonorrhoeae were screened for production of penicillinase by the intralactam strip method and chromogenic cephalosporin test. Minimum inhibitory concentrations (MICs) of penicillin, ampicillin, tetracycline, cefoxitin, cefuroxime, cefotaxime, sulphamethoxazole-trimethoprim (ratio 19/1), and spectinomycin, were measured for 100 strains by the agar dilution method. Seven (5%) of the 140 isolates were identified as penicillinase producing N gonorrhoeae (PPNG). The MICs of penicillin for the seven PPNG strains ranged from 0 X 25 mg/1 to 2 mg/1. Of the 93 non-PPNG strains, 80 (86%) were fully susceptible to penicillin with MICs ranging from 0 X 0037 mg/1 to 0 X 06 mg/1 and 13 (14%) were of intermediate penicillin resistance with MICs greater than or equal to 0 X 125 mg/1. Of the 100 isolates tested, 86% were fully susceptible to tetracycline with MICs of less than 1 mg/1. No spectinomycin resistant strains were encountered in this study. All gonococcal strains were susceptible to the cephalosporins tested as well as to sulphamethoxazole-trimethoprim.