New genetic test could slow growth of antibiotic-resistant gonorrhea

A swab of a gonorrhea strain.
A swab of a gonorrhea strain.
Nathan Reading/Flickr Creative Commons

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A UCLA professor says he has created a genetic test that can determine which gonorrhea patients can be treated with an antibiotic that has fallen out of favor, an innovation that could help slow the spread of resistance to a medication that is commonly used to treat the disease.

The test was developed by Dr. Jeffrey Klausner, who teaches medicine and public health at UCLA. It reveals which patients have a type of gonorrhea that can be treated with ciprofloxacin, or Cipro, which the Centers for Disease Control and Prevention stopped recommending in 2007 due to growing resistance to the drug.

The test also can determine whether a patient has developed resistance to Cipro, says Klausner, who points to studies showing that Cipro is highly effective in such cases.

The CDC currently recommends treating gonorrhea with two antibiotics – a shot of ceftriaxone and a pill, azithromycin. Public health experts say they have detected growing resistance to azithromycin.

"People are … essentially treated with a sledgehammer," Klausner says. "It would be much better if we could do smarter treatment and treat them on the basis of the susceptibility or the genetic characteristics of the infection they actually have."

Providers began using the lab test at UCLA's two hospitals, two emergency departments and about 150 primary care clinics in Nov. 2015. 

Klausner compared treatment of gonorrhea during the eleven months before UCLA started using the test and the eight months afterward. He found that after implementation of the test, the use of Cipro increased from zero to 34 percent of cases, according to a report in the journal Clinical Infectious Diseases.

"You increase resistance by giving people drugs that don't effectively treat them," Klausner says. "We're not going to drive further resistance by treating susceptible cases of gonorrhea with Cipro."

"We need to be able to use the best drug for the infection that the patient has and not just one-size-fits-all," he adds.

KPCC asked the CDC whether it supports using a genetic test to determine the best treatment for individual cases of gonorrhea and whether it backs the idea of doctors treating patients with Cipro when appropriate.

The agency said in a statement that the current body of evidence regarding "trends in antibiotic susceptibility and signs of emerging resistance ...  supports the use of dual therapy with azithromycin and ceftriaxone. This treatment remains effective and can help stave off resistance to both antibiotics."

The CDC added that "the limited number of treatment options available underscores the need for the development of new antibiotic agents. CDC encourages research and innovation to determine what safe and effective combination therapies could also be made available."

Klausner says he would like to see other health systems use his test before treating gonorrhea cases. He's also hopeful that researchers will develop similar tests to determine if other older antibiotics could be used to treat the infection.

"The more choices we have, the better we'll be able to control this epidemic of drug-resistant gonorrhea," he says.

Gonorrhea is the second most commonly reported disease in the country, according to the Centers for Disease Control and Prevention.