Spectinomycin as initial treatment for gonorrhoea.

The prevalence of penicillinase producing Neisseria gonorrhoeae at this hospital increased exponentially from less than 0.5% in 1978 to 6.5% of all isolates in 1982. In January 1983 first line treatment for uncomplicated heterosexual anogenital gonorrhoea was therefore changed from ampicillin and probenecid to spectinomycin. This subsequently cured 95% of cases seen at the Praed Street Clinic. Although there was an initial fall in the monthly isolation rate of penicillinase producing N gonorrhoeae after the introduction of spectinomycin, this was not maintained. The exponential increase in the prevalence of the strain did slow in 1983, rising to only 8.7%. This, however, may have reflected a general decline in the rate of increase of penicillinase producing N gonorrhoeae throughout Britain. The failure to influence the prevalence of penicillinase producing N gonorrhoeae to any great degree may have been due in part to spectinomycin resistance in both penicillinase producing and non-penicillinase-producing N gonorrhoeae. All of the isolates appeared identical, apart from the presence of the 4.4 megadalton plasmid in penicillinase producing N gonorrhoeae, but they could not be linked epidemiologically. Changing treatment in only one of the many venereal diseases clinics in London, where patients have open access to all such clinics, is unlikely to affect the prevalence of penicillinase producing N gonorrhoeae. This has probably been more important than spectinomycin resistance in limiting the effectiveness of spectinomycin in reducing the prevalence of the strain.