Concern regarding cefixime failure rate in gonorrhea patients

Jan 9 2013

By Helen Albert, Senior medwireNews Reporter

Results from a Canadian study add to those of prior studies suggesting that resistance of Neisseria gonorrhoeae to the cephalosporin antibiotic cefixime is increasing worldwide.

The researchers, led by Vanessa Allen (University of Toronto, Ontario), say that these results are concerning as cefixime is the only oral cephalosporin currently recommended for treatment of gonorrhea due to N. gonorrhoeae resistance to many previously used antibiotics.

Allen and team tested the efficacy of oral cefixime treatment in 291 Canadian individuals with culture-positive N. gonorrhoeae identified between May 2010 and April 2011. Of 133 individuals who returned for "test of cure" after treatment, 13 had a positive culture for N. gonorrhoeae and nine (6.8%) were considered to have clinical treatment failure.

Increases in the minimum inhibitory concentration (MIC) of an antibiotic needed to prevent growth of an organism are known to be a precursor to full blown antibiotic resistance.

Recent reports from Asia and Europe have shown an association between failure of cefixime treatment and organisms with an MIC of 0.12 µg/mL or greater.

Allen and colleagues found that the rate of cefixime failure was 25.0% in patients with an MIC of 0.12 µg/mL or greater compared with 1.9% in those with an MIC below 0.12 µg/mL in their cohort. This translated to a significant 13.13-fold increased risk for treatment failure in gonorrhea patients with an MIC of 0.12 µg/mL or above.

"In light of the increases in cefixime MICs among isolates of N. gonorrhoeae across North America, this study offers preliminary clinical data to support the recent Centers for Disease Control and Prevention [CDC] recommendations that cefixime is no longer optimal first-line therapy for the successful treatment of gonorrhea," write the authors in JAMA.

"New antibiotics for treating gonococcal infections are needed," emphasize Robert Kirkcaldy (CDC, Atlanta, Georgia, USA) and co-authors in an accompanying editorial.

"The threat of drug-resistant gonorrhea is increasing and has reached North America. Clinicians, drug developers, and public health professionals must act now."

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