Antibiotic-resistant phenotypes and genotypes of Neisseria gonorrhoeae isolates in Japan: identification of strain clusters with multidrug-resistant phenotypes.

OBJECTIVES

To determine the antibiotic susceptibility and the genotype distributions of N. gonorrhoeae isolates in Fukuoka, Japan, and to evaluate the specific associations between genotypes and antibiotic resistance.

METHODS

Antibiotic susceptibility testing and N. gonorrhoeae multiantigen sequence typing (NG-MAST) were performed on 242 and 239 N. gonorrhoeae isolates, respectively, in Fukuoka, Japan in 2008.

RESULTS

No isolates showed resistance to spectinomycin, ceftriaxone, or cefixime, although 34 (14.0%) and 149 (61.6%) isolates displayed decreased susceptibility to ceftriaxone (minimum inhibitory concentration range, 0.06-0.5 mg/L) and cefixime (minimum inhibitory concentration range, 0.06-0.5 mg/L), respectively. Furthermore, 171 (70.7%), 68 (28.1%), 39 (16.1%), and 1 (0.4%) isolates were resistant to ciprofloxacin, tetracycline, penicillin, and azithromycin, respectively. The 239 isolates were divided by NG-MAST into 67 sequence types (STs); the 4 most common STs were ST2958 (20.5%), ST4018 (7.5%), ST1407 (6.7%), and ST4487 (5.9%). ST2958 and ST1407 were characterized by a multidrug-resistant phenotype, whereas ST4018 and ST4487 presented a susceptible phenotype. Interestingly, ST1407, which is now common in Europe and Australia, was identified as a predominant ST in this study.

CONCLUSIONS

This is the first report combining N. gonorrhoeae antibiotic susceptibility testing with molecular typing by using NG-MAST in Japan. Although a large diversity in NG-MAST was identified, based on comparisons with the international data, the ST1407 with a multidrug-resistant phenotype currently seems to be circulating worldwide.