Gonorrhoea in London: usefulness of first line therapies.

OBJECTIVES: To determine the true prevalence and patterns of resistance of Neisseria gonorrhoeae to antimicrobial agents used for therapy in London.
METHODS: A longitudinal study of a representative sample of isolates of N gonorrhoeae linked to demographic data of infected patients was undertaken. Isolates were collected from consecutive patients attending genitourinary medicine clinics in the North and South Thames regions of London during 3 months of each of 4 years, 1997-2000. Prevalence of plasmid mediated resistance to penicillin and chromosomally mediated resistance to penicillin and ciprofloxacin was determined by susceptibility testing. The association of antimicrobial resistance among gonococci with sexual orientation of the patient and country of acquisition of infection was determined.
RESULTS: Numbers of gonococcal isolates collected over the same time period between 1997-2000 have increased by 74%. Plasmid mediated resistance to penicillin was low but has risen above 5% in 2000. Chromosomal resistance to penicillin has fallen below the 5% level but total resistance to penicillin, plasmid and chromosomally mediated, was above 5% in all 4 years. The incidence of resistance and reduced susceptibility to the alternative therapeutic choice, ciprofloxacin, is low but numbers are increasing in each year. High level resistance, to both penicillin and ciprofloxacin, has generally been found among heterosexual men and is often acquired abroad. However, there is some evidence of a change to endemic spread in 2000.
CONCLUSIONS: This surveillance programme shows that the epidemiology of gonorrhoea in London is changing with increasing numbers and changing patterns of resistance. If gonorrhoea is to be controlled and targets set by the sexual health strategy are to be met, intervention with effective and appropriate antimicrobial agents is essential.