Azithromycin-resistant Neisseria gonorrhoeae isolates in Guangzhou, China (2009–2013): coevolution with decreased susceptibilities to ceftriaxone and genetic characteristics

BMC Infectious Diseases

Research Article

Ri-Dong Yang¹  Xing-Dong Ye¹  Ping Li¹  Chao Bi¹  Xiao-Dong Li¹  Yan-Hua Liang¹  Jing-Yao Liang¹  Xiao-Xiao Chen¹  Xi-Bao Zhang¹  Wen-Ling Cao¹ 

[1] Institute of Dermatology, Guangzhou Medical University, 510095, Guangzhou, PR China;Department of Dermatology, Guangzhou Institute of Dermatology, 56 Hengfu Road, 510095, Guangzhou, PR China;

关键词: Neisseria gonorrhoeae;    Azithromycin;    Antimicrobial resistance;    NG-MAST;   

DOI  :  10.1186/s12879-016-1469-3

 received in 2015-10-22, accepted in 2016-03-14,  发布年份 2016

来源: Springer

【 摘 要 】

BackgroundThe recent emergence of azithromycin-resistant (AZM-R) N. gonorrhoeae isolates that have coevolved decreased susceptibility to extended-spectrum cephalosporins has caused great concern. Here we investigated the prevalence of decreased susceptibility to ceftriaxone (CROD) in AZM-R isolates and genetically characterized AZM-R isolates in Guangzhou, China from 2009 to 2013.MethodsThe minimum inhibitory concentration (MIC) of AZM and ceftriaxone was determined using an agar-dilution method. All AZM-R isolates were screened for mutations in 23S rRNA, mtrR and penA genes and genotyped using N. gonorrhoeae multi-antigen sequence typing (NG-MAST).ResultsOf the 485 identified N. gonorrhoeae isolates, 445 (91.8 %) were isolated from male urethritis subjects, and 77 (15.9 %) were AZM-R (MIC ≥ 1 mg/L), including 33 (6.8 %) with AZM low-level resistant (AZM-LLR, MIC = 1 mg/L) and 44 (9.1 %) with AZM middle-level resistant (AZM-MLR, MIC ≥ 2 mg/L). Significantly more CROD (MIC ≥ 0.125 mg/L) showed in AZM-MLR isolates (43.2 %, 19/44) as compared with that in AZM-LLR isolates (18.2 %, 6/33) (p < 0.05). For the 23S rRNA, mtrR, penA or combined 23S rRNA/MtrR/penA mutations, no significant difference was found between AZM-LLR isolates and AZM-MLR isolates (P > 0.05); similar results were detected between combined AZM-LLR/CROD isolates and combined AZM-MLR/CROD isolates (P > 0.05). No mutation A2059G or AZM high-level resistant (AZM-HLR, MIC ≥ 256 mg/L) isolate was detected. Among 77 AZM-R isolates, 67 sequence types (STs) were identified by NG-MAST, of which 30 were novel. Most STs were represented by a single isolate.ConclusionsThe AZM-R together CROD isolates are now present in Guangzhou, China, which deserve continuous surveillance and the mechanism of concurrent resistance needs further study.

【 授权许可】

CC BY   
© Liang et al. 2016