Researchers have identified a new strain of gonorrhea that is resistant to cephalosporin, the only antibiotic that can be used to treat the disease. The new strain of gonorrhea, labeled H041, has only been found in a very few infections. But the strain has doctors worried for two reasons: First, it does not respond to treatment with any known antibiotic. Second, in the lab, it rapidly passed the genes for resistance to other strains of gonorrhea. The team wrote in their report abstract, “This is a large public health problem and the era of untreatable gonorrhea may now have been initiated.” The development may soon leave doctors powerless to treat second most common sexually transmitted disease (STD) in the world.
Japanese and European researchers presented their findings at the annual meeting of the International Society for Sexually Transmitted Diseases Research [http://www.isstdr.org/] on July 10, only three days after researchers from the U.S. Centers for Disease Control and Prevention (CDC) warned of the emergence of such a strain. Researchers from the U.S. Centers for Disease Control and Prevention (CDC) reported in the July 7 issue of the Morbidity and Mortality Weekly Report (MMWR), that forms of gonorrhea resistant to cephalosporins are emerging around the globe.
No cases of cephalosporin-resistant gonorrhea have been reported yet in the United States, but the report describes a troubling trend, said CDC researchers. Resistant bacteria are emerging in the same pattern as they did for fluoroquinolones. Widespread resistance to fluoroquinolones developed during the 1990s and early 2000s. In that case, resistant strains of gonorrhea were first seen in Asia, then Hawaii, then the United States.
If cephalosporin resistance becomes widespread, no known antibiotics will be available to treat gonorrhea.
An Overview of Gonorrhea
Gonorrhea is a sexually transmitted disease (STD) caused by infection with the bacterium Neisseria gonorrhoeae. Gonorrhea is the most common sexually transmitted disease in the United States. Gonorrhea is transmitted through any type of sexual contact, including vaginal, anal, and oral. It can also be passed from a woman to her baby during childbirth.
Worldwide and in the United States, gonorrohea is second most common sexually transmitted disease (STD) after chlamydia. The CDC estimates that nearly 700,000 cases of gonorrhea occur each year in the United States, although less than half of them are reported to the CDC. Worldwide, 62.35 million people were infected with gonorrhea in 1999. The highest rates of infection are in Latin America and the Carribean, Sub-Saharan Africa, and South and Southeast Asia.
Neisseria gonorrhoeae thrives in warm, moist environments such as the urethra, the mouth and throat, and the female reproductive tract (including the cervix, fallopian tubes, and uterus). The bacterium can also grow in the eyes. In women, gonorrhea is a leading cause of pelvic inflammatory disease, ectopic pregnancy, and infertility. In men, gonorrhea can lead to epididymitis, a painful swelling of the tube that joins the testicle to the vas deferens. Left untreated, epididymitis may lead to infertility. Unchecked, gonorrohea can affect joints or the blood, a serious and often life-threatening condition.
Gonorrhea also increases the risk of transmission of the human immunodeficiency virus (HIV), the virus that causes AIDS – in both directions. People with gonorrhea are more susceptible to HIV infection. Conversely, people with gonorrhea who are also infected with HIV can transmit HIV more easily than if they did not have gonorrhea.
Cephalosporins are the only class of antibiotics that remain effective against gonorrhea. Two cephalosporin drugs are used to treat gonorrhea: cefixime, a cephalosporin drug taken orally, and cefriaxone, an injectable cephalosporin medication.
Resistance is Increasing in the United States
For the CDC report, researchers analyzed nearly 6000 test samples for resistance to cephalosporins. They used a measure called minimum inhibitory concentrations (MIC) to determine whether the bacteria in the samples had developed resistance to cephalosporins. MIC is a way to measure how much of an antibiotic is needed to stop a bacterium from growing.
A very small percentage of samples showed increased resistance to cephalosporins. But researchers expressed concern about the increase in resistance since 2000. Increased resistance to cephalosporins grew from 0.2 percent in 2000 to 1.4 percent in 2010 for cefixime, and from 0.1 percent in 2000 to 0.3 percent in 2010 for ceftriaxone. Most of that increase occurred during the latter part of the decade. Resistance to cefixime rose from 0.02 percent during 2000-2006 to 0.11 percent during 2009-2010. Samples were not tests during 2007-2008.
Cepholosporin resistance was more prevalent among men who had sex with men. Geography also made a difference: rates fell along a west-to-east gradient. The greatest increases in resistance to cefixime were found in Hawaii (0% in 2000 to 7.7% in 2010), followed by California (0% in 2000 to 4.5% in 2010).
Can a Gonorrhea Pandemic be Averted?
Colloquially called “the clap” or “the drip,” gonorrhea has plagued humanity for nearly a thousand years or more. In 1167, the English Parliament signed into law an act that described symptoms similar to gonorrhea and called for a reduction in the “perilous infirmity of burning.”
It wasn’t until 1940, with the introduction of sulfa drugs, that gonorrhea could be cured. But the wily bacterium soon developed resistance to both sulfa drugs. During the 1980s, resistance to penicillin and tetracycline became widespread. By the turn of the century, gonorrhea had developed widespread resistance to ciprofloxacin and other drugs in the class of fluoroquinolones.
“The potential emergence of gonococcal cephalosporin resistance is of particular concern because the U.S. gonorrhea control strategy relies upon effective antibiotic therapy,” the CDC researchers wrote in an accompanying editorial note. The best ways to prevent the spread of gonorrhea is to use a condom with every sexual encounter, have sex only with one uninfected partner, and
Yet prevention resources are limited, and gonorrhea is a difficult infection to control, even with strong prevention messages. The researchers added: “In light of the diminished resources available to STD control programs and the past inability to prevent emergence of resistance, the eventual emergence of cephalosporin resistance appears likely.”
The CDC research team recommends that any person diagnosed with gonorrhea should be thoroughly evaluated and treated. Any disease that does not respond to initial treatment should be cultured and treated with an injection of 250 mg ceftriaxone and two grams oral azithromycin. All sex partners from the preceding two months should be tested, preferably with culture, and treated with the same regime. The CDC requested that all health-care providers who suspect treatment failures to report promptly to local and state health departments. The agency also asked agencies to keep cultures in stock so testing can be done quickly.
The CDC team emphasized the importance of prompt action on the part of clinicians, patients, and public health officials. “Actions undertaken now could delay the spread of cephalosporin-resistant strains and mitigate the public health consequences,” they wrote.
References
AVERT. STD Statistics Worldwide. http://www.avert.org/std-statistics.htm
Centers for Disease Control and Prevention. (Last update 5 April, 2011). Gonorrhea – Fact Sheet. Retrieved from http://www.cdc.gov/std/gonorrhea/stdfact-gonorrhea.htm
Centers for Disease Control and Prevention. (8 July, 2011) Cephalosporin Susceptibility Among Neisseria gonorrheae Isolates — United States, 2000-2010. MMWR. 60; (26); 873-877. Available at http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6026a2.htm
Sanger, W. (2010). A History of Prostitution. NY: Harper.