Antimicrobial Susceptibility of Ertapenem in Neisseria gonorrhoeae Isolates Collected Within the China Gonococcal Resistance Surveillance Programme (China-GRSP) 2018

Wen-Qi Xu,1,2 Xiao-li Zheng,1,2 Jing-Wei Liu,1,2 Qian Zhou,1,2 Xiao-Yu Zhu,1,2 Jin Zhang,1,2 Yan Han,1,2 Kai Chen,1,2 Shao-Chun Chen,1,2 Xiang-Sheng Chen,1,2 Yue-Ping Yin1,2 1STD Reference Laboratory, Institute of Dermatology and Hospital for Skin Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, People’s Republic of China; 2STD Reference Laboratory, National Center for Sexually Transmitted Diseases Control, Chinese Center for Disease Control and Prevention, Nanjing, People’s Republic of ChinaCorrespondence: Yue-Ping YinSTD Reference Laboratory, Institute of Dermatology and Hospital for Skin Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, People’s Republic of ChinaTel/Fax +86 258 547 8024Email yinyp@ncstdlc.orgPurpose: This study aimed to determine the minimum inhibitory concentrations (MICs) of ertapenem on Neisseria gonorrhoeae collected from eight Chinese provinces in 2018.Methods: The MICs of ertapenem on 503 Neisseria gonorrhoeae isolates (415 isolates selected randomly and 88 isolates selected with preference) were measured using the agar dilution method. For comparison, the MICs of ceftriaxone and azithromycin were detected.Results: Among 415 randomly selected isolates, the MIC range for ertapenem was from ≤ 0.008 mg/L to 0.5 mg/L. The corresponding MIC50 and MIC90 were 0.06 and 0.125 mg/L, respectively. Twelve of 415 isolates (2.9%) exhibited MIC values ≥ 0.25 mg/L, and only one isolate (0.2%) had a MIC of 0.5 mg/L. By comparing all 503 tested isolates, a correlation of r = 0.487 (P < 0.001) between ertapenem and ceftriaxone MIC was observed, and the correlation between MICs of ertapenem and azithromycin was low (r = − 0.12, P = 0.007). In 24 ceftriaxone-decreased susceptibility isolates, four isolates (16.7%) showed a MIC ≥ 0.25 mg/L for ertapenem. In 85 azithromycin resistant isolates, three isolates (3.5%) showed a MIC ≥ 0.25 mg/L for ertapenem.Conclusion: T