HIGH PREVALENCE OF NEISSERIA-GONORRHOEAE STRAINS WITH REDUCED SUSCEPTIBILITY TO FLUOROQUINOLONES IN JAPAN

Objective-To study the antibiotic susceptibility of Neisseria gonorrho eae strains isolated in Japan and, in particular, to examine the possi bility of emerging fluoroquinolone resistance. Materials and methods-S ixty-nine strains of Neisseria gonorrhoeae isolated in 1992 were teste d for susceptibility to 15 antibiotics including fluoroquinolones and were seroclassified. Twenty-seven strains isolated from 1981 to 1984 w ere also evaluated as controls. Results-The MIC90 values of norfloxaci n, ofloxacin, and ciprofloxacin against the isolates from 1992 were 2. 0, 1.0, and 0.5 mu g/ml, respectively. The MIC90 values of norfloxacin , ofloxacin, and ciprofloxacin against the isolates from 1981-84 (cont rols) were 0.25, 0.125, and 0.063 mu g/ml, respectively. These results indicate that the MIC90 values of norfloxacin, ofloxacin, and ciprofl oxacin against the strains from 1992 were 8-fold higher than those aga inst the strains from 1981-84. However, there were no significant diff erences in susceptibility to beta-lactams, tetracyclines, macrolides, and spectinomycin between the isolates from 1992 and those from 1981-8 4. The majority of the isolates belonged to the WII/WIII serogroup. Th ere was no relationship between fluoroquinolone resistance and serogro up. Conclusions-Fluoroquinolones have been used frequently as first-li ne therapy and have provided excellent clinical efficacy for gonococca l infections for the last several years in Japan. However, our data in dicate that a rapid decrease in the susceptibility of Neisseria gonorr hoeae to fluoroquinolones is occurring in our country.