Summary of ceftriaxone-resistant Neisseria gonorrhoeae in Canada, 2017–24

Objective From 2017 to 2024, there were 16 cases of ceftriaxone-resistant gonorrhoea in Canada, 8 of which were isolated in 2024, including one XDR case. We describe the clinical and demographic details of all 16 cases and examine the phenotypic and molecular characteristics of each case. To investigate the relatedness of the cases both to each other and to international isolates, a phylogenetic tree was constructed. Methods All 16 ceftriaxone-resistant isolates underwent WGS and were compared to the international isolates. Antimicrobial susceptibility testing was completed by agar dilution following the CLSI protocol. Results Ceftriaxone MICs for the 16 isolates range between 0.25 and 2 mg/L. All cases were isolated from genital sites, and four cases were probable treatment failures. Ten of the cases were linked to international travel. Seven of the isolates were part of the NG-STAR ST 233 clonal complex. All 16 cases have penA alleles associated with cephalosporin resistance, including penA 60.001, penA 121.002, penA 237.001 and penA 294.002. Conclusion We summarize 16 cases of ceftriaxone-resistant gonorrhoea that were isolated in Canada from 2017 to 2024. We determined the penA allele type for each case and detected molecular markers associated with cephalosporin resistance. Local public health investigations and the genomic data for each case indicate that the strains did not spread further in the population. To date, ceftriaxone remains an effective treatment for gonorrhoea, but continued surveillance is required to ensure detection and thus prevent the further spread of ceftriaxone-resistant Neisseria gonorrhoeae in Canada.