A microbiological study of failed penicillin therapy for gonococcal urethritis in Durban.

Seventy-five men presenting with persistent urethral discharge after penicillin therapy were investigated for sexually transmitted pathogens during July - September 1987. The major aetiological agent isolated was Neisseria gonorrhoeae (58 patients (77.3%]. Penicillinase-producing N. gonorrhoeae (PPNG) accounted for 58.6% of 58 isolates. Chlamydia trachomatis was detected in 10.7% of patients and Trichomonas vaginalis in 14.7% of patients. When there is a high prevalence of PPNG, the use of penicillin as a first-line agent for therapy should be discontinued in favour of an agent active against PPNG and non-PPNG strains. Furthermore, in view of the relatively high prevalence of T. vaginalis, patients returning with persistent urethral discharge should be investigated and treated for infection with this protozoan.