Cefixime for N. gonorrhoeae produced high treatment failure in Toronto
A sexual health clinic in Toronto reported high clinical failure after treatment with cefixime for Neisseria gonorrhoeae infections, researchers reported in The Journal of the American Medical Association.
“This study is the first demonstration of a relatively high rate of clinical failure associated with the use of cefixime for the treatment of gonorrhea in North America and Europe,” Vanessa Allen, MD, MPH, medical microbiologist and infectious diseases specialist at Public Health Ontario, told Infectious Disease News. “Isolates with cefixime minimum inhibitory concentrations (MICs) of 0.12 mcg/mL were associated with a 25% rate of clinical failure within our cohort, suggesting a need for the reevaluation of clinical breakpoints.”
In August, the CDC updated its gonorrhea treatment guidelines and recommended that cefixime (Suprax, Lupin Pharmaceuticals) no longer be used because of increased reports of resistance. It currently recommends ceftriaxone and injectable cephalosporin, combined with azithromycin or doxycycline. If cefixime is used, patients need to have a test of cure.
Allen and colleagues conducted a retrospective cohort study of patients who attended a single clinic from May 1, 2010, to April 30, 2011. As per the Public Health Agency of Canada Sexually Transmitted Guidelines during the study period, patients with suspected or confirmed N. gonorrhoeae infections received 400 mg cefixime.
Of the 291 patients, 133 patients returned for a test of cure. Thirteen of these patients had cultures positive for N. gonorrhoeae at the repeat test, and nine were classified as treatment failures. Among those who returned for the test of cure, the rate of clinical treatment failure associated with cefixime was 6.77% (95% CI, 3.14-12.45). All nine patients were treated successfully, six with 250 mg ceftriaxone and three with 800 mg cefixime.
When the cefixime MIC was 0.12 mcg/mL or higher, the rate of clinical treatment failure was 25%. If the MIC was 0.12 mg/mL or lower, the rate of clinical treatment failure was 1.9%.
“The CDC and WHO suggest that a drug should no longer be used as empiric therapy when more than 5% of isolates demonstrate resistance,” Allen said. “If 0.12 mcg/mL is deemed to be a more appropriate resistance breakpoint, many regions in the United States have already reached that threshold according to the most recent data from the Gonococcal Isolate Surveillance Program.”
Allen said that this study provides evidence to support the recommendation that cefixime no longer be used for gonorrhea treatment. However, resistance to ceftriaxone, the last recommended gonorrhea treatment, is also on the rise, she said.
“Proactive and novel strategies to prevent, diagnose and treat gonorrhea are required,” Allen said. “These include combination antimicrobial therapies, increased use of culture and routine test of cure, particularly when suboptimal therapy is used.”
Disclosure: Allen reports no relevant financial disclosures.
Vanessa Allen, MD, MPH, can be reached at Public Health Ontario Laboratories, 81 Resources Road, Toronto, ON, M9P 3T1; email: Vanessa.firstname.lastname@example.org.