Abstract：bjective To investigate the susceptibility to ceftriaxone and the prevalence of NG-MAST genotypes of Neisseria gonorrhoeae in Guangdong, China. To explore the correlation between MIC and NG-MAST genotypes. Methods A total of 285 N. gonorrhoeae isolates were collected from 2010 to 2016 in Guangdong, China. The susceptibility of the isolates to ceftriaxone were tested using the agar dilution method recommended by CLSI. DNA was extracted by Qiagen commercial kit and NG-MAST was performed using the molecular typing method. Results All isolates were susceptible to ceftriaxone (CLSI standard: S≤0.25μg/mL) except one isolate (MIC 0.5μg/mL).
The proportion of Neisseria gonorrhoeae with MIC≥0.06μg/mL was 63.2%. The proportion of isolates with MIC≥0.06μg/mL in 2010 and 2016 was 70.6% and 44.4% respectively. A total of 166 genotypes were identified and 93 genotypes were new. The prevalent cluster included ST 568 (n=13), ST270 (n=9), ST421 (n=7), ST2288 (n=5), ST1731 (n=4), ST1766 (n=4), ST1866 (n=4), ST1870 (n=4), ST1053 (n=4), ST2318 (n=4), ST5990 (n=4), ST1614 (n=4), and ST1866 (n=3). Isolates with identical or similar genotypes have similar MIC to ceftriaxone. Conclusion Ceftriaxone and spectinomycin were recommended to be used for Gonorrhoea treatment in Guangdong. The prevalent diversity of N. gonorrhoeae genotypes suggested a fluctuation in sexual network in this region. The correlation between genotypes and MIC suggested that NG-MAST can be used as a genetic marker in the antibiotic susceptibility surveillance system.