title: Neisseria gonorrhoeae treatment failure and susceptibility to cefixime in Toronto, Canada.
abstract: OBJECTIVE
  Although cephalosporins are the cornerstone of treatment of Neisseria gonorrhoeae infections, cefixime is the only oral antimicrobial option. Increased minimum inhibitory concentrations (MICs) to cefixime have been identified worldwide and have been associated with reports of clinical failure.
  
  
  OBJECTIVE
  To assess the risk of clinical treatment failure of N. gonorrhoeae infections associated with the use of cefixime.
  
  
  METHODS
  A retrospective cohort study of culture-positive N. gonorrhoeae infections at a single sexual health clinic in Toronto, Canada, that routinely performs test of cure. The cohort comprised N. gonorrhoeae culture-positive individuals identified between May 1, 2010, and April 30, 2011, treated with cefixime as recommended by Public Health Agency of Canada guidelines.
  
  
  METHODS
  Cefixime treatment failure, defined as the repeat isolation of N. gonorrhoeae at the test-of-cure visit identical to the pretreatment isolate by molecular typing and explicit denial of reexposure.
  
  
  RESULTS
  There were 291 N. gonorrhoeae culture-positive individuals identified. Of 133 who returned for test of cure, 13 were culture positive; 9 patients were determined to have experienced cefixime treatment failure, involving urethral (n = 4), pharyngeal (n = 2), and rectal (n = 3) sites. The overall rate of clinical treatment failure among those who had a test of cure was 6.77% (95% CI, 3.14%-12.45%; 9/133). The rate of clinical failure associated with a cefixime MIC of 0.12 μg/mL or greater was 25.0% (95% CI, 10.69%-44.87%; 7/28) compared with 1.90% (95% CI, 0.23%-6.71%; 2/105) of infections with cefixime MICs less than 0.12 μg/mL, with a relative risk of 13.13 (95% CI, 2.88-59.72; P < .001).
  
  
  CONCLUSIONS
  The rate of clinical failure following treatment of N. gonorrhoeae infections with cefixime was relatively high at a Toronto clinic and was associated with elevated MICs.
authors.affiliation: Public Health Ontario Laboratories, 81 Resources Rd, Toronto, ON M9P 3T1, Canada. vanessa.allen@oahpp.ca
authors.forename: Vanessa G
authors.initials: VG
authors.lastname: Allen
authors.forename: Leo
authors.initials: L
authors.lastname: Mitterni
authors.forename: Christine
authors.initials: C
authors.lastname: Seah
authors.forename: Anuradha
authors.initials: A
authors.lastname: Rebbapragada
authors.forename: Irene E
authors.initials: IE
authors.lastname: Martin
authors.forename: Colin
authors.initials: C
authors.lastname: Lee
authors.forename: Heather
authors.initials: H
authors.lastname: Siebert
authors.forename: Lynn
authors.initials: L
authors.lastname: Towns
authors.forename: Roberto G
authors.initials: RG
authors.lastname: Melano
authors.forename: Donald E
authors.initials: DE
authors.lastname: Low
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D020682:Cefixime / Q000494:pharmacology* / Q000627:therapeutic use; D015331:Cohort Studies; D004352:Drug Resistance, Microbial; D005260:Female; D006069:Gonorrhea / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009344:Neisseria gonorrhoeae / Q000187:drug effects / Q000302:isolation & purification*; D009864:Ontario; D012189:Retrospective Studies; D012306:Risk; D017211:Treatment Failure; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D020682:Cefixime