[Epidemic of penicillinase-producing, tetracycline-resistant gonococci; risk factors for their spread].

Objective: To assess whether the 1989 epidemic of tetracycline-resistant (TRNG) and penicillinase-producing Neisseria gonorrhoeae (PPNG) was caused by a small number of imported strains, and what the risk factors for infection were.

Design: Retrospective.

Setting: The National Institute of Public Health and Environmental Protection (NIPHEP).

Method: A total of 1257 questionnaires were sent to the 5 microbiological laboratories which had contributed most to the number of isolates sent to NIPHEP, in order to obtain additional information of all patients infected in 1989 and 1990 with PPNG. Of all these patients the results of quantitative sensitivity testing, auxotype, serotype and plasmid pattern of the PPNG were obtained.

Results: The questionnaire response was 1047/1257 (83.3%). A part of the isolates from the non-responders was included in the study. Determinations were performed in 1185 PPNG isolates (94.3%). In 1988 and 1989 an increase of TRNG among PPNG was observed. The PPNG isolates in 1989 (n - 472) and 1990 (n = 713) from 5 laboratories in Amsterdam. Rotterdam and The Hague, showed that the epidemic was caused mainly by the spread of three strains. NR/IB-6, PRO/IA-3 and PRO/IA-6. The introduction probably took place in The Hague in 1988 and import from abroad could not be confirmed. The TRNG risk was increased for men and women over 40 years and for men from The Hague and Rotterdam having contacts with prostitutes; the latter did not apply to Amsterdam. For women, a Turkish or Latin American nationality increased the TRNG risk.

Conclusion: Because of the continuing threat of developing resistance and the instability of microbiological characteristics of gonococci, a continuous national surveillance is necessary, including information about risk factors for infection with resistant gonococci, to improve the control of the infection.