Molecular screening to track ceftriaxone-resistant FC428-like Neisseria gonorrhoeae strains’ dissemination in four provinces of China, 2019 to 2021

BackgroundThe global dissemination of ceftriaxone-resistant <i>Neisseria gonorrhoeae</i> FC428-like strains poses a public health concern. To assess and follow their spread, establishing effective antimicrobial resistance (AMR) surveillance systems is essential.AimThis study aimed to track ceftriaxone-resistant FC428-like strains in parts of China, using a molecular screening tool.MethodsSamples were collected from Sichuan, Zhejiang, Shanghai, and Guangdong provinces between 2019 and 2021. We employed a rapid molecular tool - the high-resolution melting analysis-based FC428 (HRM-FC428) assay, to screen for FC428-like strains. All FC428-like strains detected were further characterised by genotyping and PCR-sequencing.ResultsOf 1,042 tested samples, 44 harboured the <i>penA</i>-60.001 allele linked to ceftriaxone resistance, revealing a 4.2% prevalence of FC428-like strains. The HRM-FC428 assay additionally uncovered six strains with mosaic <i>penA</i>-195.001 or <i>penA</i>-232.001 alleles, both bearing the A311V mutation, a ceftriaxone resistance marker. During the study, the prevalence of FC428-like strains among overall samples appeared to increase, with rates of 2.8% (11/395) in 2019, 4.2% (16/378) in 2020, and 6.3% (17/269) in 2021. Some strains' sequence types (ST)s were identified across provinces (e.g. ST1903, ST1600) and most strains (24/44) were ST1903, an ST also reported in other regions/countries, suggesting local evolution and global transmission.ConclusionOur work underscores the value of culture-independent antimicrobial resistance monitoring and validates the use of molecular diagnostic tools, like the HRM-FC428 assay for this purpose. This study offers insights into the complex landscape of ceftriaxone-resistant <i>N. gonorrhoeae</i>, emphasising the importance of continued surveillance and global collaboration to mitigate this growing public health threat.