Detection of penicillinase-producing Neisseria gonorrhoeae

Abstract

The estimated annual global number of gonococcal infections in the 1960s was 60 million, and during the 1970s this rose to approximately 200 million. Since its introduction in 1944, penicillin has been widely and successfully used in the treatment of gonorrhoea, although strains of Neisseria gonorrhoeae with decreased susceptibility of penicillin have been recognised since 1958. The effective therapeutic dosage of penicillin has been increased steadily to cope with chromosome-mediated increasing resistance of the gonococcus. Higher doses of penicillin, given together with probenecid to enhance blood levels, has maintained the balance in favour of penicillin. However, in 1976 penicillinase-producing N. gonorrhoeae (PPNG) strains emerged. Epidemiological data, including plasmid analysis, suggest that there are two separate endemic zones of infection, one in South-east Asia and the other in West Africa, while in recent years the prevalence of PPNG has increased markedly in certain parts of Europe. Although the majority of infections with PPNG reported in the United Kingdom are acquired in South-east Asia and West Africa, in 1979 41 patients (39% of the total infections with PPNG strains) contracted their infections in the United Kingdom. As the prevalence of PPNG strains increases, routine testing of all gonococcal isolates for penicillinase-production becomes more important. With low prevalence, such tests have been restricted to those isolates with reduced sensitivity to penicillin, or isolates from cases of penicillin treatment failure. Of the tests used by laboratories to detect PPNG isolation, a choice has to be made.