ATLANTA, July 14 (UPI) -- Having beaten each antibiotic used against it over the last several decades, gonorrhea is now showing resistance to the primary drug currently used against it, according to a new report.
Although azithromycin is effective against gonorrhea, the U.S. Centers for Disease Control and Prevention reports the resistance to the drug has more than quadrupled over the course of the most recent reporting year, leaving experts concerned it will soon be ineffective, according to a report released today.
Gonorrhea rates have increased continuously for several years in the United States, with 350,062 cases reported in 2014, making it the second most common sexually transmitted infection in the country behind chlamydia. Rates have also increased in Europe, where the increase has been called "constant", and the rest of the world.
While rarely life-threatening, the infection can cause pelvic inflammatory disease in women, which can lead to infertility, ectopic pregnancy and chronic pelvic pain. The infection also can get into the blood stream to reach other parts of the body, and is also thought to facilitate HIV and AIDS infection.
The CDC's recommendation for treating gonorrhea is a combination therapy, pairing an oral dose of azithromycin with an injected dose of ceftriaxone, and is generally effective at clearing the infection because if one drug does not work against it, the other is expected to.
CDC experts are not surprised the bacteria, Neisseria gonorrhoeae, is evolving to resist the drug as it has against every other antibiotic used against it.
"We think the combination therapy can prolong the treatment efficacy, but we know eventually it will develop resistance," Dr. Robert Kirkcaldy, lead researcher on the new CDC report, told UPI. "What's happened with gonorrhea is it's a smart bug that mutates. It has sequentially knocked through [other antibiotics] like dominoes, and as the resistance has grown, the CDC has changed its guidelines."
The study on drug efficacy against gonorrhea, published with the agency's latest Morbidity and Mortality Weekly Report, is based on 5,093 isolates collected in 2014 at 27 STI clinics across the country and tested by the CDC.
Resistance to azithromycin increased from 0.6 percent in 2013 to 2.5 percent in 2014, a significant increase, though still behind the 25.3 percent resistance to tetracycline, 19.2 percent resistance to ciprofloxacin and 16.2 percent resistance to penicillin.
The CDC is working to increase resources on research for doctors to find faster ways of culturing and testing drugs against strains of the bacteria, though Kirkcaldy said funding and efforts to find new drugs need to be stepped up.
A big part of the problem, however, is the spread of the disease and increased screening, so that people who have gonorrhea can help prevent spread, methods for which come down to abstinence or proper use of condoms.
"This is a pattern that we did not expect to see," Kirkcaldy said of the significant increase in gonorrhea resistance, adding, however, that "the bug develops resistance though, and it's not a matter of if but when."