Aug. 7 (UPI) -- A new test for gonorrhea can determine whether those infected will respond successfully to the inexpensive oral antibiotic ciprofloxacin, according to a study published Friday by Clinical Infectious Diseases.
Once a common treatment of the sexually transmitted infection, the drug has been used less in recent years because of concerns the bacteria that causes the disease was becoming resistant to the medication.
In the study, the test identified 106 people infected with a strain of gonorrhea called wild-type gyrA serine, all of whom were cured after a single dose of oral ciprofloxacin, known commonly as Cipro, the researchers said.
"[Our] new lab can accurately predict drug resistance in gonorrhea, and by using that test we can safely treat many patients and partners with an oral antibiotic to slow resistance," study co-author Dr. Jeffrey Klausner, a professor of medicine in the division of infectious diseases at UCLA, told UPI.
The test gives doctors another choice to treat the sexually transmitted infection and could help slow the spread of drug-resistant gonorrhea, he said.
Gonorrhea is one of the most common drug-resistant infections worldwide, and growing resistance to available treatments is making it increasingly harder to treat, Klausner said.
Nearly 600,000 people are diagnosed with the sexually transmitted infection in the United States each year, the U.S. Centers for Disease Control and Prevention estimates.
As many as one in five cases are caused by bacteria resistant to ciprofloxacin, meaning the bacteria have evolved and no longer respond to the antibiotic, the CDC has said.
Ciprofloxacin was used to treat gonorrhea until 2007, when the CDC stopped recommending its use, Klausner said.
As a result, many of those infected are treated with antibiotic injections -- usually ceftriaxone -- that are expensive and can be painful, he said. About 1% of gonorrhea strains are resistant to ceftriaxone, according to the CDC.
But roughly 70% to 80% percent of gonorrhea infections in the United States still can be treated with ciprofloxacin, Klausner said.
"Using a pill instead of a shot would also make it easier and faster to treat sex partners of patients with gonorrhea because they don't have to come back in to the clinic for a shot, but can just go to a pharmacy to pick up the pill," said Klausner, who also is an adjunct professor of epidemiology at the UCLA Fielding School of Public Health.
The new test is designed to detect a particular genetic mutation in gonorrhea bacteria that makes it resistant to ciprofloxacin.
Ciprofloxacin is highly effective against infections without the mutation, Klausner said.
He and his colleagues have been working on the test since 2006, but the Clinical Infectious Diseases study marks the first time it's been tested on humans. Larger studies involving more patients with gonorrhea are needed, however, to confirm the accuracy of the test, they said.
"We hope that in the near future the test can be incorporated into a rapid 20-minute gonorrhea [screening] and the doctor and patient will know at that same visit if ciprofloxacin can be safely used, which will really accelerate the time to treatment and result in a decrease in the further spread of infection," Klausner said