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

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 beta lactamase producing profiles. RESULTS Among the 87 isolates obtained, only one isolate was revealed to produce beta lactamase. MIC90 values for ciprofloxacin, levofloxacin, gatifloxacin, and moxifloxacin were over 8 microg/ml, over 8 microg/ml, 4 microg/ml, and 2 microg/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 microg/ml and 0.0063 microg/ml. All isolates were sensitive to ceftriaxone and 90.8% of them were sensitive to cefixime. MIC90 for spectinomycin was 32 microg/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.