Emergence and genomic characterization of the ceftriaxone-resistant Neisseria gonorrhoeae FC428 clone in Chengdu, China

Abstract Objectives To verify the contribution of the globally disseminated Neisseria gonorrhoeae FC428 clone to the emergence of ceftriaxone resistance in Chengdu in south-west China during 2018. Methods Antimicrobial susceptibility of the N. gonorrhoeae isolates to six antibiotics was determined using the agar dilution method. A real-time PCR assay and WGS were used to identify the FC428 clone. Phylogenomic and molecular antimicrobial resistance analyses were conducted to characterize the transmission and evolution of related strains. Results Four out of 112 N. gonorrhoeae isolates were confirmed as the ceftriaxone-resistant FC428 clone. Phylogenomic analysis revealed that they resulted from multiple introductions and subsequent local transmissions. The strains have undergone further evolutions characterized by the accumulation of mutations in resistance-associated genes and/or the acquisition of plasmids encoding penicillin and tetracycline resistance genes. Conclusions The N. gonorrhoeae FC428 clone has spread to south-west China. Efforts should be made to enhance gonococcal antimicrobial surveillance to control further dissemination of this successful clone at both local and national levels.