Antimicrobial resistance of Neisseria gonorrhoeae in the municipality of Morón, Cuba: emergence of isolates with intermediate resistance to fluoroquinolones

Sir, Gonorrhoea remains a significant disease globally. The consequences of a high disease rate include a high incidence of complications and long-term morbidity, as well as increased HIV transmission. The emergence of antimicrobial resistance in Neisseria gonorrhoeae is a major obstacle in the control of gonococcal infections. In response to the increasing frequency of isolation of penicillinand tetracycline-resistant strains of N. gonorrhoeae, the WHO has recommended the use of fluoroquinolones or broad-spectrum cephalosporins for the primary treatment of uncomplicated gonorrhoea.1 In 1998, the Cuban Ministry of Public Health implemented the Syndromic Approach to sexually transmitted disease (STD) management, using 500 mg of single-dose oral ciprofloxacin as therapy in persons with urethral or vaginal syndromes in two Cuban municipalities: Camaguey and Santiago de Cuba, extending its use to the rest of the country late in 2001.2 In an attempt to identify the prevalent status of gonococcal resistance to antibiotics, the municipality of Moron, located in the north-east region of Cuba, joined the national monitoring network in 1999 as a participating territory. Forty-five isolates of N. gonorrhoeae were studied, recovered from 1100 symptomatic persons of both sexes in Moron between November 1999 and April 2000. The isolates were identified by standard laboratory techniques.3 Susceptibilities to penicillin, tetracycline, cefuroxime, ceftriaxone, cefotaxime, spectinomycin and ciprofloxacin were determined by disc diffusion, using GC agar base medium supplemented with 1% Vitox (Oxoid), as described by the NCCLS.4 The gonococcal reference strain ATCC 49226 was used as a control. The isolates were also tested for β-lactamase production by the iodometric method.3 Of the 45 strains, 25 (55.6%) were resistant and five (11.1%) exhibited intermediate resistance to penicillin. Of the 25 strains that were resistant to penicillin, 23 (92%) were penicillinase-producing N. gonorrhoeae (PPNG) strains. Forty per cent of isolates were tetracycline resistant and 8.9% exhibited reduced susceptibility. All strains were susceptible to cefuroxime, cefotaxime, ceftriaxone and spectinomycin. Interestingly, in our study 8.8% of isolates exhibited reduced susceptibility to ciprofloxacin. Three of these four gonococcal strains were also PPNG and resistant to tetracycline and the other was susceptible. This is the first documentation in a Cuban municipality or even a province in which more than one isolate of N. gonorrhoeae was detected displaying decreased susceptibility to the fluoroquinolones. Given that most strains of N. gonorrhoeae with diminished susceptibility to ciprofloxacin respond to recommended fluoroquinolones in single doses, ciprofloxacin 500 mg or norfloxacin 400 mg,5 the Cuban Programme for Control of STD will continue to recommend 500 mg of ciprofloxacin as therapeutic choice in the syndromic management of urethral/ vaginal syndromes in Moron. A limitation of this study is the small sample size. However, the high prevalence of gonococci with intermediate susceptibility to ciprofloxacin strongly indicates the need to continue monitoring the susceptibilities of gonococcal isolates to ciprofloxacin and other fluoroquinolones in this municipality. This might ensure that such strains do not become an endemic reservoir from which resistant strains and highly resistant strains may be selected, which has been reported in Asia and the Western Pacific Region.1,5 The proportion of gonococcal strains resistant to penicillin and tetracycline is too high in Moron, as in the rest of Cuba, to recommend these antibiotics for the treatment of gonorrhoea in this country.2,3,6