Penicillinase producing gonococci: a spent force?

Abstract

Though the incidence of gonorrhoea caused by penicillinase producing Neisseria gonorrhoeae (PPNG) strains at St Mary's Hospital rose rapidly from 1980 to reach 6.2% in 1982, it declined in 1983 (8.6%) and in 1984 (6.5%), a trend that has continued in 1985. The use of penicillinase stable antibiotics or more effective contact tracing are unlikely to be responsible for this recent decline. We have always isolated very few PPNG strains from homosexual men, and the possible effects of the acquired immune deficiency syndrome (AIDS) on sexual behaviour in this group is therefore unlikely to be relevant. We have seen a steady increase in the proportion of PPNG strains carrying the 4.4 megadalton penicillinase plasmid (67% of PPNG strains in 1984). Strains carrying both the 4.4 megadalton plasmid and the 24.5 megadalton conjugal plasmid were very common in 1982, but since then have declined in importance. PPNG strains carrying the 3.2 megadalton plasmid have become less common, and the presence of the 24.5 megadalton plasmid in these strains has not apparently led to their wider dissemination in the community. Whereas the basic pattern of PPNG auxotypes has changed little, since 1982 we have isolated an increasing number of mixed auxotypes with nutritional requirements other than just proline. PPNG strains carrying the 4.4 megadalton plasmid seem to be more resistant to erythromycin, tetracycline, and streptomycin than those carrying the 3.2 megadalton plasmid. Spectinomycin resistance has only occurred in strains carrying the 4.4 megadalton plasmid.