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.
To assess the risk of clinical treatment failure of N. gonorrhoeae infections associated
with the use of cefixime.
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.
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.
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).
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.