Prevalence of and risk factors for quinolone-resistant Neisseria gonorrhoeae infection in Ontario.
BACKGROUND
Quinolone-resistant Neisseria gonorrhoeae has swiftly emerged in Canada. We sought to determine its prevalence in the province of Ontario and to investigate risk factors for quinolone-resistant N. gonorrhoeae infection in a Canadian setting.


METHODS
We used records from the Public Health Laboratory of the Ontario Agency for Health Protection and Promotion in Toronto, Ontario, and the National Microbiology Laboratory in Winnipeg, Manitoba, to generate epidemic curves for N. gonorrhoeae infection. We extracted limited demographic data from 2006 quinolone-resistant N. gonorrhoeae isolates and from a random sample of quinolone-susceptible isolates. We also extracted minimum inhibitory concentrations for commonly tested antibiotics.


RESULTS
Between 2002 and 2006, the number of N. gonorrhoeae infections detected by culture decreased by 26% and the number of cases detected by nucleic acid amplification testing increased 6-fold. The proportion of N. gonorrhoeae isolates with resistance to quinolones increased from 4% to 28% over the same period. Analysis of 695 quinolone-resistant N. gonorrhoeae isolates and 688 quinolone-susceptible control isolates from 2006 showed a higher proportion of men (odds ratio [OR] 3.1, 95% confidence interval [CI] 2.3-4.1) and patients over 30 years of age (OR 3.1, 95% CI 2.4-3.8) in the quinolone-resistant group. The proportion of men who have sex with men appeared to be relatively similar in both groups (OR 1.4, 95% CI 1.1-1.8). Quinolone-resistant strains were more resistant to penicillin (p < 0.001), tetracycline (p < 0.001) and erythromycin (p < 0.001). All isolates were susceptible to cefixime, ceftriaxone, azithromycin and spectinomycin.


CONCLUSIONS
During 2006 in Ontario, 28% of N. gonorrhoeae isolates were resistant to quinolones. Infections in heterosexual men appear to have contributed significantly to the quinolone resistance rate. Medical practitioners should be aware of the widespread prevalence of quinolone-resistant N. gonorrhoeae and avoid quinolone use for empiric therapy.
Ota
Kaede V
KV
Division of Microbiology, Pediatric Laboratory Medicine, The Hospital for Sick Children, 555 University Ave., Toronto, Ontario.
Jamieson
Frances
F
Fisman
David N
DN
Jones
Karen E
KE
Tamari
Itamar E
IE
Ng
Lai-King
LK
Towns
Lynn
L
Rawte
Prasad
P
Di Prima
Alessandro
A
Wong
Tom
T
Richardson
Susan E
SE
D000328:Adult; D000367:Age Factors; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D006069:Gonorrhea / Q000188:drug therapy* / Q000453:epidemiology; D018451:Homosexuality, Male / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D009344:Neisseria gonorrhoeae; D009864:Ontario / Q000453:epidemiology; D010406:Penicillins / Q000627:therapeutic use; D015995:Prevalence; D015363:Quinolones / Q000627:therapeutic use*; D012307:Risk Factors; D012737:Sex Factors; D055815:Young Adult
D000900:Anti-Bacterial Agents; D010406:Penicillins; D015363:Quinolones