Detection of non-travel-associated, ceftriaxone non-susceptible Neisseria gonorrhoeae FC428-like harbouring the mosaic penA60 allele in Ontario, Canada.

BACKGROUND

This case report describes a young male with multidrug-resistant Neisseria gonorrhoeae infection acquired in Ontario, Canada with no travel history.

METHODS

Case follow-up was conducted following routine public health practice in Ontario. Antimicrobial susceptibility testing of the isolate was done by agar dilution. Strain typing and other molecular characterization was done by whole genome sequencing.

RESULTS

The patient was treated successfully with intramuscular ceftriaxone and oral azithromycin. Agar dilution testing demonstrated reduced susceptibility to all tested agents, except for azithromycin and spectinomycin, including non-susceptibility to ceftriaxone (minimum inhibitory concentration [MIC]=0.5 mg/L) and cefixime (MIC=2 mg/L), resistance to tetracycline (MIC=2 mg/mL) and ciprofloxacin (MIC=32 mg/L), and testing intermediate to penicillin (MIC=1 mg/L). Whole-genome sequencing revealed the isolate was closely related to the FC428 clone, which harbours the mosaic penA60 allele responsible for elevated MICs to extended-spectrum cephalosporins, such as ceftriaxone or cefixime, both currently recommended as first-line or alternative treatment options for uncomplicated anogenital gonorrhea infections in Ontario.

CONCLUSION

Identification of this case suggests previously unrecognized local transmission of this multidrug-resistant N. gonorrhoeae strain is occurring in Ontario and highlights the need for ongoing surveillance to monitor trends and inform treatment recommendations.