Neisseria gonorrhoeae treatment failure to the recommended antibiotic regimen-Quebec, Canada, 2015-19

Abstract

Objective: To describe Neisseria gonorrhoeae treatment failure to the recommended antimicrobial regimens (azithromycin, cefixime and ceftriaxone). Methods: Our study was a longitudinal analysis of treatment failures from an observational open cohort of gonococcal infection cases collected in Quebec, Canada (n=2547) between September 2015 and December 2019. Epidemiological and clinical data were collected using a self-Administered questionnaire, direct case interviews and chart reviews. Antimicrobial susceptibility testing was performed using the agar dilution method. To be retained as a treatment failure, cases must have had (i) a laboratory-confirmed gonococcal infection; (ii) a documented treatment; (iii) a positive test of cure (TOC) performed within a defined period and (iv) no sexual contact (vaginal, oral or anal), even protected with a condom, between the beginning of treatment and the positive TOC. A broader definition, including suspected cases, was also examined. Results: Among 1593 cases where a TOC was performed, 83 had a positive TOC: 11 were retained as treatment failure, and 6 were considered suspected cases (overall=17/1593; 1.1%). Possible explanations for retained or suspected treatment failure included resistance to the antibiotics used for treatment (n=1), pharyngeal infection (n=9, of which 5 had been treated with ceftriaxone and 4 with other regimens); and azithromycin monotherapy (n=1). Some cases had more than one potential explanation. Conclusions: Treatment failure occurred in 1.1% of cases of Neisseria gonorrhoeae infection for which a TOC was performed, including some cases of pharyngeal infection treated with ceftriaxone.