Correlation between in vitro Quinolone Susceptibility of Neisseria gonorrhoeae and Outcome of Treatment of Gonococcal Urethritis with Single-Dose Ofloxacin

Since the introduction of quinolones for treating gonococcal urethritis, we have used single-dose ofloxacin as the first-line antibiotic for 12 years in Hong Kong with much success. In 1990, we documented a trend of decreasing ofloxacin susceptibility of gonococci. Because of an increasing incidence of treatment failure, which we encountered with emergence of quinolone-resistant Neisseria gonorrhoeae, the initial treatment regimen for all cases of acute gonococcal urethritis was stepped up from 400 to 600 mg of ofloxacin in November 1995. The increased dosage appeared satisfactory in terms of patients' responses, until further clusters of treatment failures again began to appear around mid-1996. This retrospective study examined case records of all patients with culture-proven gonococcal urethritis seen in our sexually transmitted disease (STD) clinics and studied the correlation between pretreatment susceptibility of gonococci and outcome of treatment with single-dose ofloxacin therapy.