Identification of multidrug-resistant Neisseria gonorrhoeae isolates with combined resistance to both ceftriaxone and azithromycin, China, 2017–2018

The growing multidrug-resistant Neisseria gonorrhoeae is a serious global threat to gonococcal therapy. During 2017–2018, we identified a rare multidrug-resistant (ceftriaxone and azithromycin) strain (GC250) and four strains (GC185, GC195, GC196 and GC249) with both resistance to ceftriaxone and decreased susceptibility to azithromycin. All strains belonged to NG-STAR ST1143, including the mosaic penA-60.001, which is closely related to ceftriaxone resistance. The characterization of antimicrobial resistance (AMR) determinants and phylogenetic analysis showed these five strains were closely related to internationally spreading ceftriaxone-resistant N. gonorrhoeae FC428, but with higher azithromycin MIC. Findings here demonstrated that this clone not only initiated clonal expansion in China, but acquired azithromycin resistance.