High Prevalence of Ceftriaxone-Resistant Neisseria gonorrhoeae in Hanoi, Vietnam, 2023-2024

Abstract

Ceftriaxone resistance in Neisseria gonorrhoeae is an escalating global health concern, threatening the efficacy of empiric treatment. In the Asia-Pacific region, a rapid surge in ceftriaxone resistance has been observed, primarily associated with the penA-60.001 allele. This study, conducted in Hanoi, Vietnam between 2023 and 2024, analyzed 352 N. gonorrhoeae isolates and found a 27% prevalence of ceftriaxone resistance. Whole-genome sequencing identified that resistance was predominantly driven by the mosaic penA-237.001 allele, with a smaller contribution from penA-60.001. The high prevalence of resistance and the emergence of new alleles underscore the urgent threat to ceftriaxone as an empiric treatment option.

Keywords: Asia, Southeastern; antimicrobial resistance; ceftriaxone; gonorrhea; whole-genome sequencing.

Figure 1.

Phylogenetic relatedness of 90 Neisseria gonorrhoeae isolates from Hanoi, Vietnam with ceftriaxone alert values (minimum inhibitory concentrations ≥ 0.125 mg/L). A, ML tree (midpoint rooted) of 90 isolates collected at Hanoi Medical University Hospital between January 2023 and June 2024. In addition, 6 well-characterized N. gonorrhoeae reference isolates were included in this panel: 5 WHO reference strains, WHO D, WHO Q (2018, UK), WHO R (FC428, 2015, Japan), WHO X (H041, 2009, Japan), and WHO Y (F89, 2010, France), and 1 ceftriaxone-resistant strain (F92) linked to Vietnam (2022, France). The ML tree is based on 2088 SNP differences detected across the whole core genome of the isolate panel and was visualized using iTOL version 6.9.1. MLST are annotated on the ring around the ML tree and penA alleles are depicted as symbols on the branch leaves. Separate ML phylogenetic trees of isolates belonging to clade 1 (B) based on 706 core SNPs and clade 2 (C) based on 367 core SNPs are depicted to provide higher granularity. D, A median joining tree of clade 1. Each circle represents a unique genome, and the size of the circle is proportional to the number of isolates sharing that genome. Hatch marks on the edges connecting the genomes represent the number of SNPs between genomes. Node color corresponds to penA alleles. Abbreviations: ML, maximum likelihood; MLST, multilocus sequence type; SNP, single-nucleotide polymorphism; WHO, World Health Organization.