Gonorrhea guide: Etiology and epidemiology

On this page

• Etiology
• Epidemiology
• Surveillance of antimicrobial resistance in gonorrhea
• References

Etiology

Neisseria gonorrhoeae is a Gram-negative diplococcus^{Footnote 1}. This highly infectious bacterium colonizes and infects genital mucosa and it may also infect extragenital sites, including the oropharyngeal, conjunctival and anorectal mucosae^{Footnote 2}.

N. gonorrhoeae can develop antimicrobial resistance (AMR) rapidly and has developed resistance to every class of antimicrobial used to treat it^{Footnote 3Footnote 4}; some of these antibiotics (sulphonamides, penicillins, tetracyclines) are ineffective and are no longer used.

Travel-related ceftriaxone-resistant gonorrhea isolates have been reported in Canada ^{Footnote 5Footnote 6} and isolates with decreased susceptibility to cephalosporins (cefixime and ceftriaxone) continue to emerge. Resistance to azithromycin is increasing and treatment failures have been reported in Canada and around the world.

Epidemiology

Gonorrhea is the second most commonly reported sexually transmitted infection (STI) in Canada, with a gradual and steady increase in reported cases of gonorrhea since 2012^{Footnote 7}. In 2021, 32,192 cases of gonorrhea were reported in Canada for a rate of 84.2 cases per 100,000 people. The reported rate of gonorrhea doubled between 2012 and 2021, with rates higher among males than females. In 2021, gonorrhea rates were highest among females aged 15 to 29 years old and males aged 20 to 39 years old^{Footnote 8}.

It is important to note that as asymptomatic gonorrhea infections may be undiagnosed and underreported, reported case counts and rates of gonorrhea may underestimate the true prevalence of gonorrhea in Canada^{Footnote 9 Footnote 10}.

More information

Local epidemiological information: Consult your public health unit.

National epidemiological information:

• Notifiable Diseases Online
• STBBI surveillance resources and publications
• Report on sexually transmitted infection surveillance in Canada, 2019
• Report on the Enhanced Surveillance of Antimicrobial-Resistant Gonorrhea (ESAG): Results from 2018 to 2021

Global epidemiological information:

• Enhanced Gonococcal Antimicrobial Surveillance Programme (EGASP): Surveillance report 2022
• Report on global sexually transmitted infection surveillance, 2018

Surveillance of antimicrobial resistance in gonorrhea

Gonococcal antimicrobial resistance: A global health challenge

Antimicrobial-resistant N. gonorrhoeae is a significant global public health challenge^{Footnote 3}, posing a serious threat to effective treatment of gonococcal infections and raising the possibility of infections becoming untreatable in the future^{Footnote 11}. Surveillance of AMR in N. gonorrhoeae is crucial to monitor trends and inform efforts to prevent and control its spread.

In 2020, approximately 90% of gonorrhea cases were diagnosed using Nucleic Acid Amplification Testing (NAAT). As a result, fewer samples are available for susceptibility testing, making it difficult to generate an accurate picture of drug resistance^{Footnote 11}.

Azithromycin resistance and decreased susceptibility to cephalosporins among N. gonorrhoeae isolates have been on the rise in Canada. In 2021, 7.6% of N. gonorrhoeae isolates were resistant to azithromycin, surpassing the 5% cut-off recommended by the World Health Organization^{Footnote 12Footnote 13}.

Treatment failures have also been reported with the use of third generation oral^{Footnote 14Footnote 15} and injectable cephalosporins. Cases of gonorrhea with high-level resistance to both ceftriaxone and azithromycin have been reported in Canada, the United Kingdom, Australia and Hawaii^{Footnote 6Footnote 16Footnote 17}.

In Canada, multidrug-resistant cases of gonorrhea have decreased considerably between 2017 (12.2%) and 2021 (7.8%)^{Footnote 13}. N. gonorrhoeae was shown to be resistant to ciprofloxacin, erythromycin, penicillin, and tetracycline^{Footnote 13}.

Gonococcal Antimicrobial Surveillance Programme

Since 1985, the Gonococcal Antimicrobial Surveillance Programme (GASP - Canada) has operated as a passive national surveillance program. GASP - Canada plays a crucial role in investigating treatment failures, outbreaks, and antimicrobial resistance though antimicrobial susceptibility testing and molecular characterization on N. gonorrhoeae isolates obtained from cultures^{Footnote 12}.

Enhanced Surveillance of Antimicrobial-Resistant Gonorrhea

The Enhanced Surveillance of Antimicrobial-Resistant Gonorrhea (ESAG) program integrates epidemiologic and treatment failure data into existing laboratory-based monitoring of antimicrobial-resistant N. gonorrhoeae. ESAG information enables early identification of drug-resistant gonorrhea and assists in identifying appropriate and effective treatment, which helps prevent its spread.