Antimicrobial Susceptibility Evaluation and Multiple-Locus Variable Number Tandem Repeat Analysis of Neisseria gonorrhoeae Isolates in China in 2012.

OBJECTIVE: This study aimed to gain information on the antimicrobial susceptibility and molecular epidemiological typing of Neisseria gonorrhoeae (NG) isolates in China in 2012.

METHODS: A total of 244 NG isolates were consecutively recovered from patients with uncomplicated gonorrhea attending sexually transmitted disease clinics in 3 Chinese cities-Guangzhou, Nanjing, and Tianjin-in 2012. Neisseria gonorrhoeae susceptibilities to penicillin and tetracycline were examined by detecting penicillinase-producing NG (PPNG) and high-level tetracycline-resistant NG, and NG susceptibilities to ciprofloxacin, spectinomycin, ceftriaxone, and cefixime were determined using an agar dilution method. Neisseria gonorrhoeae isolates were typed by multiple-locus variable number tandem repeat analysis. We conducted a χ analysis to compare clusters with Bonferroni correction and Kruskal-Wallis test.

RESULTS: Neisseria gonorrhoeae isolates gathered from the 3 cities differed significantly in the prevalence of tetracycline-resistant NG (P < 0.001) and NG treated with ceftriaxone with a minimum inhibitory concentration of 0.125 mg/L or higher (P < 0.001). The analysis of the combination of the 7 variable number of tandem repeats loci for all of the 244 isolates yielded 110 multiple-locus variable number tandem repeat analysis types falling into 5 clusters. Cluster III was associated with PPNG, whereas cluster II was associated with non-PPNG (P < 0.05) and NG treated with ceftriaxone with a minimum inhibitory concentration of 0.125 mg/L or higher (P < 0.05).

CONCLUSIONS: Antimicrobials that can be used with confidence to treat NG infection currently in China include ceftriaxone and spectinomycin, but not penicillin, tetracycline, ciprofloxacin, and cefixime. Moreover, some of the resulting clusters were associated with PPNG and NG with decreased ceftriaxone susceptibility.