Gonorrhoeae (Neisseria gonorrhoeae)
Gonorrhea, an infection caused by Neisseria gonorrhoeae, has been nationally notifiable since 1924 and remains the second most commonly reported bacterial sexually transmitted infection in Canada. Untreated infections can lead to complications for both sexes, with more severe consequences for women. A serious, common complication affecting women is pelvic inflammatory disease, which can lead to chronic abdominal pain, infertility, and ectopic pregnancy. In men, untreated infections can result in epididymitis and rare cases of infertility. An uncommon complication of gonorrhea is the spread of infection to the blood stream and joints3. Like other non-ulcerative STIs, gonorrhea can increase the risk of HIV acquisition and transmission possibly by increasing the concentration of cells in genital secretions. These cells can serve as targets for HIV thereby increasing the risk of acquiring and/or transmitting the virus2b.
While reported rates of gonorrhea infections in Canada continue to rise in both sexes, the increase is being driven by women in more recent years.
- From 1991 to 1997, male and female rates of gonorrhea infection decreased dramatically; following 1997, sex-specific rates increased at a gradual pace until 2008 (Figure 5).
- In 2008, 12,723 cases of gonorrhea infections were reported nationally, corresponding to a rate of 38.2 per 100,000 (Figure 5). The overall rate increased by 116.5% since 1999 (17.6 per 100,000).
- Between 1999 and 2008, reported rates in both sexes increased over time. Rates in males increased by 95.1% (from 22.0 to 42.9 per 100,000) and in females by 151.1% (from 13.3 to 33.5 per 100,000) (Figure 5).
- More recently, the reported rate has stabilized in men, while continuing to increase in women. From 2007 to 2008, the reported rate increased by 1.4% in men and by 12.2% in women.
Figure 5: Reported Rates of Gonorrhea by Sex and Overall, 1991 to 2008, Canada
Reported rates of gonococcal infections in 2008 were highest in the younger population.
- People under 30 years of age accounted for the majority (71.5%) of reported cases in 2008. This is in contrast with infectious syphilis, in which the same age group accounted for only 26.3% of reported cases.
- The highest reported rate of gonorrhea infections in women was in 15 to 19 year olds (186.6 per 100,000) and 20 to 24 year olds (166.3 per 100,000) (Figure 6). The highest reported rate in men was in 20 to 24 year olds (165.4 per 100,000) followed by 25 to 29 year olds (122.5 per 100,000) (Figure 6).
Figure 6: Reported Rates of Gonorrhea by Sex and Age Group, 2008, Canada
Reported rates of gonococcal infections increased consistently over time across age groups in both males and females aged 15 and older.
- In males, the greatest absolute increase in reported rates of gonococcal infections was seen in 20 to 24 year olds (Figure 7). The rate increased from 70.0 per 100,000 in 1999 to 165.4 per 100,000 in 2008.
- Although reported rates in older men remained low compared to other age groups, substantial increases were seen since 1999, especially in men aged 60 and older. Reported rates in senior men increased by 99.5% from 2.0 per 100,000 in 1999 to 4.0 per 100,000 in 2008 (Figure 7).
Figure 7: Reported Rates of Gonorrhea in Males by Age Group, 1999 to 2008, Canada
- In women, the greatest absolute increase in reported rates of gonococcal infections was seen in 15 to 19 year olds. The rate increased from 79.5 per 100,000 in 1999 to 186.6 per 100,000 in 2008 (Figure 8).
Figure 8: Reported Rates of Gonorrhea in Females by Age Group,
1999 to 2008, Canada
- Although reported rates in older women remained low compared to other age groups, substantial increases were seen since 1999, especially in women aged 30 to 39. The rate in 30 to 39 year olds increased by 287.4% (from 7.7 to 29.9 per 100,000) (Figure 8).
While the reported rates were highest in Nunavut and the Northwest Territories, the Prairie Provinces have seen substantial increases between 1999 and 2008.
- In 2008, the highest number of gonorrhea cases was reported in Ontario, followed by Alberta and Québec (Table 2). However, reported rates were highest in the Northwest Territories and Nunavut, followed by Manitoba, and Saskatchewan (Table 2).
- Between 1999 and 2008, the greatest increase in reported rates was in Saskatchewan, with an increase of 346.6% (Table 2). While the increase in Newfoundland and Labrador seems large at first glance, the overall number of reported cases remains small (Table 2).
Table 2: Reported Cases and Rates1 of Gonorrhea by Province/Territory,
1999 and 2008, Canada
||Number of Cases
||Rate per 100,0003
||Rate Change (%)
1 Rate change calculated using unrounded values.
2 Nunavut did not officially become a territory until 1999; prior to 1999, data for Nunavut was combined with Northwest Territories. Rate change for NT was not calculated since 1999 rates are not comparable with 2008 rates due to the creation of Nunavut.
* The rate change cannot be quantified.
3 Bolded rates indicate rates above national average.
- In 2008, the national male-to-female rate ratio was 1.3:1, reflecting that more males than females were reported with gonococcal infections (Table 3). However, this average masks variations across the country. In four jurisdictions (Prince Edward Island, Manitoba, Saskatchewan and Yukon Territory), more cases were reported in females than males.
Table 3: Male-to-Female Ratio of Reported Rates of Gonorrhea by Province/Territory, 2008, Canada
||Male-to-Female Rate Ratio
||1.3 : 1.0
||1.8 : 1.0
||1.3 : 1.0
||0.7 : 1.0
||0.8 : 1.0
||1.4 : 1.0
||1.8 : 1.0
||1.1 : 1.0
||1.1 : 1.0
||0.3 : 1.0
||0.7 : 1.0
||1.0 : 1.0
||1.0 : 1.0
Uncomplicated gonorrhea can be treated with single dose oral or injectable antibiotics. The challenge arises when resistant strains are treated with antibiotics to which the bacteria have decreased susceptibility. When this occurs, there is increased likelihood of transmission due to treatment failure and the development of adverse sequelae unless the resistant organism is identified and treated appropriately. Gonococcal resistance to penicillin, erythromycin and tetracycline is long established, while ciprofloxacin resistance has developed more recently4-6. None of these antibiotics are currently recommended as preferred treatments in the Canadian Guidelines on Sexually Transmitted Infections1b.
- Canadian gonococcal resistance surveillance is a collaborative effort between the National Microbiology Laboratory (NML) at PHAC and provincial and territorial laboratories.
- Submission to the NML of gonococcal isolates that have decreased susceptibility to at least one antibiotic is voluntary and not standardized across the country.
- Further, the shift from culture to Nucleic Acid Amplification Test (NAAT) has created challenges in monitoring resistance as specimens available for testing are becoming more limited.
- Antibiotics tested for gonococcal resistance at the NML include penicillin, tetracycline, spectinomycin, erythromycin, azithromycin, ciprofloxacin, cefixime and ceftriaxone.
- Using the most current data available for 2007, 30.2% of cultured strains demonstrated resistance to ciprofloxacin, up from 2.4% in 2003 (Figure 9).
- While azithromycin is one of the drugs included for surveillance, less than 1% of tested strains show resistance each year.
- In 2007, 0.2% of cultured strains demonstrated resistance to azithromycin. Note that these strains were from three jurisdictions and the overall numbers were low.
Figure 9: Antimicrobial Susceptibility of Neisseria gonorrhoeae Strains Tested in Canada, 1999-2007
* Percentages are calculated using the number of all GC cultures tested in each province, including susceptible and resistance cultures, as the denominator.
There are no resistant strains for spectinomycin, cefixime, and ceftriaxone.
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