July 7, 2011 -- The CDC is warning that gonorrhea resistant to known antibiotic treatments could soon be a reality in the United States.
A report in Friday’s Morbidity and Mortality Weekly Report highlights gonorrhea's declining susceptibility to cephalosporins, which is the only remaining class of antibiotics available to treat the common sexually transmitted disease (STD).
While cephalosporin treatment failures have not been documented in the U.S., CDC officials say they are seeing “concerning trends” that suggest such failures are not far off.
“We do fear that based on what we are hearing around the world, we will see cephalosporin-resistant gonorrhea,” CDC Director of STD Prevention Gail Bolan, MD, tells WebMD. “We don’t know when this is going to happen, but the hope is that we have a few years to identify other treatments.”
Challenges of Gonorrhea Treatment
Bolan points out that since sulfonamides became the first successful gonorrhea treatment in the 1940s, emerging antibiotic resistance has been a frequent challenge.
“First we lost our ability to use sulfa drugs to treat gonorrhea and then we lost penicillin,” she says.
And in just the last decade, growing resistance to ciprofloxacin and other drugs in the class of antibiotics known as fluroquinolones led the CDC to recommend against their use for the treatment of gonorrhea.
Bolan says the pattern of resistance now emerging for the oral cephalosporin drug cefixime and the injectable cephalosporin ceftriaxone is strikingly similar to that seen with the fluroquinolones.
For both drug classes, the first reports of treatment failures came from Asia. The first evidence of declines in drug susceptibility in the U.S. have occurred on the West Coast.
The July 8 Morbidity and Mortality Weekly Report includes an analysis of cephalosporin susceptibility for nearly 6,000 test samples collected annually between 2000 and 2010. Drug susceptibility was analyzed based on minimum inhibitory concentrations (MIC), which is a measure of the lowest concentration of antibiotics needed to stop a bacterium’s growth in the lab.
Western U.S. Most Affected
The analysis revealed that:
- While the overall number of test samples that were found to have decreased susceptibility to cefixime was small, a concerning increase was seen in recent years -- from 0.02% in 2000 through 2006 to 0.11% in 2009 and 2010.
- Twelve of the 13 specimens from 2009-2010 with decreased susceptibility to cefixime were from men who have sex with men.
- The Western United States saw the biggest elevations in declining susceptibility; Hawaii had the biggest increases during the period (from 0% to 7.7%), followed by California (0% to 4.5%).
Suspicious Gonorrhea Should Be Cultured
Bolan warns that new antibiotics may soon be needed to effectively treat gonorrhea, but she says drug companies have shown little interest in developing such drugs.
The CDC is working with the National Institutes of Health (NIH) to identify effective drugs that may already be available and to study new ones.
And the agency is asking health care providers to follow current treatment guidelines, which require two antibiotics. The CDC also recommends that health care providers change their diagnostic practices if they suspect a patient might have treatment-resistant gonorrhea.
The CDC is recommending that cultures be performed on patients whose symptoms do not get better or return quickly following treatment if drug resistance is suspected.
The CDC is also asking health care providers to promptly report all suspected treatment failures to local or state health departments, and the agency is asking health departments to keep cultures on hand so that testing can be done quickly.
“Providers have always been on the front lines of this type of surveillance,” Hillard Weinstock, MD, of the CDC’s Division of STD Prevention, tells WebMD. “This is the way public health agencies find out what is going on in their communities.”