The Centers for Disease Control and Prevention (CDC) reported yesterday that the bacterium that causes gonorrhea, the second most common sexually transmitted disease (STD) in the United States, is growing increasingly resistant to its primary recommended treatment.
In a study published in the CDC's Morbidity and Mortality Weekly Report (MMWR), researchers said isolates of Neisseria gonorrhoeae collected in 2014 showed that rates of resistance to the antibiotic azithromycin quadrupled from 2013.
Because gonorrhea has become increasingly resistant to several other antibiotics that have been used to treat it, the CDC recommends that gonorrhea infections be treated with a combination of azithromycin (taken orally) and ceftriaxone (injected).
'Need for immediate action'
In a total of N gonorrhoeae 5,093 isolates collected in 2014 as part of a nationwide surveillance program, the percentage that were resistant to azithromycin rose to 2.5%, up from 0.6% in 2013, while resistance to cefixime rose from 0.4% to 0.8% and resistance to ceftriaxone remained at 0.1%.
The CDC says it's unclear whether the numbers are temporary or mark the beginning of a trend. But the study's authors warned that the emergence of resistance to both azithromycin and ceftriaxone "would complicate gonorrhea treatment substantially."
"The increases are cause for concern and highlight the need for immediate action on a number of fronts to ensure that our ability to treat people with gonorrhea stays intact," corresponding author Robert Kirkcaldy, MD, MPH, of the CDC's Division of STD Prevention, told CIDRAP News.
Kirkcaldy said it's important to note that there haven't been any treatment failures yet in the United States, but he suggested a sense of urgency is warranted.
"Because history shows us that resistance to our current antibiotics will develop, it is critical that we take steps now by strengthening our surveillance efforts, identifying new treatment options, and ensuring local STD prevention services are available to those who need them," Kirkcaldy said.
Concerns over gonorrhea becoming untreatable
The CDC said that more than 350,000 US gonorrhea cases were reported in 2014, although it estimates that there are as many as 800,000 cases each year. Among men, rates of gonorrhea infection have been steadily rising since 2009.
The sexually transmitted pathogen spreads through unprotected vaginal, oral, and anal sex, and can infect both men and women. It generally causes infections in the genitals, rectum, and throat, and pregnant women can pass the infection along to their newborns during childbirth. Serious and permanent health problems can emerge if the disease goes untreated.
Prevention of gonorrhea transmission relies on prompt detection and effective antimicrobial treatment. But since the beginning of the antimicrobial era, gonorrhea has exhibited a capacity to mutate and develop resistance to the drugs used to treat it, sometimes over the span of only two decades.
In the current study, 25% of the isolates tested were resistant to tetracycline, while 19% were resistant to ciproflaxin and 16% were resistant to penicillin. That's why public health experts say the development of resistance to the current treatment is so troublesome.
"It is a worry," said Ruth Lynfield, MD, Minnesota state epidemiologist and medical director at the Minnesota Department of Health. "As we continue to lose classes (of antibiotics), we're worried we'll have untreatable gonorrhea."
The CDC said that doctors should continue to treat gonorrhea with the dual therapy of azithromycin and ceftriaxone, as it is believed that most strains of the infection will respond to one of the drugs if they are resistant to the other. Doctors are encouraged to avoid the use of azithromycin on its own, since that could encourage further resistance.
In September 2015, doctors in Leeds, England, confirmed several cases of gonorrhea resistant to azithromycin, prompting an investigation by British health officials.
See also:
Jul 15 CDC MMWR report
