Effectiveness of norfloxacin and ofloxacin for treatment of gonorrhoea and decrease of in vitro susceptibility to quinolones over time in Rwanda

Abstract

Objective-To study the effectiveness of single-dose norfloxacin and of loxacin in the treatment of gonococcal urethritis in men, and to monitor in vitro antimicrobial susceptibility to these antibiotics over time. Setting-Centre Médico-Social de Bilyogo, Kigali, Rwanda. The only clinic in Rwanda using quinolones for the treatment of gonorrhoea. Method-As part of a monitoring progranume, men with gonococcal urethritis were evaluated after treatment with norfloxacin (800 mg) in 1986 and 1987, and after treatment with of loxacin (400 mg) in 1989. Results-Neisseria gonorrhoeae was eradicated from the urethra from 96.0% (1891197) and from 97-1% (1661171) men treated with norfloxacin and ofloxacin, respectively. Overall 38-2% of the pretreatment isolates produced penicillinase (PPNG isolates) and 20-4% (441216) of the tested non-PPNG isolates were chromosomally resistant to penicillin (MIC k220 mgIl). Resistance to tetracycline and thiamphenicol was common in both PPNG and non-PPNG and increased considerably in 1989. All isolates were susceptible to kanamycin, spectinomycin, ceftiaxone, norfloxacin, ofloxacin and ciprofloxacin. However, a higher number of isolates recovered in 1989 showed decreased susceptibility to the quinolones. Treatment failure occurred more often in subjects with isolates having MIC values k0-06 mg/L of norfloxacin (p = 0.006). Seven out of 13 patients who did not respond to therapy had no signs nor symptoms of urethritis. Conclusion-Quinolone antibiotics are now indicated as a first line treatment of gonorrhoea in countries with a problem of antimicrobial multiresistance. However, antimicrobial susceptibility to the quinolones may decrease rapidly, and close monitoring of the in vitro susceptibility of N gonorrhoeae and the clinical effectiveness of the antibiotics is imperative.