Susceptibilities of Neisseria gonorrhoeae to fluoroquinolones and other antimicrobial agents in Hyogo and Osaka, Japan

Abstract

Objectives: Decreasing susceptibility of Neisseria gonorrhoeae to fluoroquinolones has been reported in several countries. Knowledge of local N gonorrhoeae susceptibilities to various antimicrobials is important for establishing a rational treatment strategy in each region.

Methods: Isolates of N gonorrhoeae from male urethritis patients attending four urological clinics in Hyogo and Osaka prefectures in Japan were collected during 2002. The MICs for nine antimicrobials: penicillin G, tetracycline, cefixime, ceftriaxone, levofloxacin, gatifloxacin, ciprofloxacin, moxifloxacin, and spectinomycin were determined for each isolate. All isolates were also tested for β lactamase producing profiles.

Results: Among the 87 isolates obtained, only one isolate was revealed to produce β lactamase. MIC₉₀ values for ciprofloxacin, levofloxacin, gatifloxacin, and moxifloxacin were over 8 μg/ml, over 8 μg/ml, 4 μg/ml, and 2 μg/ml, respectively. The proportion of isolates resistant to fluoroquinolones was over 60% (ciprofloxacin, 70.1%; levofloxacin, 65.5%; gatifloxacin, 70.1%). Chromosomally mediated penicillin and tetracycline resistance was identified in 12.6% and 33.3% of the isolates. MIC₉₀ values for cefixime and ceftriaxone and were 0.5 μg/ml and 0.0063 μg/ml. All isolates were sensitive to ceftriaxone and 90.8% of them were sensitive to cefixime. MIC₉₀ for spectinomycin was 32 μg/ml and all isolates were sensitive to it. Fluoroquinolone resistance correlated significantly with MICs for penicillin G but not tetracycline.

Conclusion: Ceftriaxone and spectinomycin demonstrated lower MICs and so are recommended for N gonorrhoeae. Susceptibilities of N gonorrhoeae should be monitored periodically by region.