Friday, April 20, 2012
Public health officials are sounding the alarm on the growing threat of multi-drug resistant gonorrhea. What will it take to turn the tide against gonorrhea, the second most commonly reported communicable disease in the United States?
"Though there is no evidence yet of treatment failures in the United States, trends in decreased susceptibility coupled with a history of emerging resistance and reported treatment failures in other countries point to a likelihood of failures on the horizon and a need for urgent action," says Judith Wasserheit, MD, MPH, professor and vice chair of the Department of Global Health at the University of Washington in Seattle and co-author of a new analysis of the emerging threat..sup.1
Gonorrhea is the second most commonly reported communicable disease in the United States. The Centers for Disease Control and Prevention (CDC) estimates that more than 700,000 persons in the United States get new gonorrheal infections each year..sup.2 Neisseria gonorrhoeae, the bacteria that causes the sexually transmitted infection (STI), is wily in its resistance to antimicrobial agents. It developed resistant to sulfanilamide in the 1940s, penicillins and tetracyclines in the 1980s, and fluoroquinolones by 2007. Third-generation cephalosporins are the first-line treatment options now recommended by the CDC..sup.3
Drugs losing ground
The effectiveness of cephalosporins for treating gonorrhea is decreasing rapidly, warns the CDC..sup.4
Researchers with the CDC's Gonococcal Isolate Surveillance Project have reported a 17-fold increase in elevated minimum inhibitory concentrations, which serve as a measure of drug susceptibility. In the past, national treatment recommendations have been changed to focus on other effective drugs when resistance to drugs has increase; however, there are no other drugs available to successfully treat the infection.
"The bottom line is that gonorrhea is a very complex bacteria, and we've seen it evolve and become resistant to every antibiotic recommended for treatment over the years," says Gail Bolan, MD, director of the CDC's Division of STD Prevention. "In the past, CDC has kept pace with this evolving organism, monitoring for trends in susceptibility and changing treatment guidelines as needed because we had alternative antibiotics to use.
However, public health officials are at an impasse, since there are no new drugs in development, and new options are urgently needed, says Bolan, who serves as lead author of the current analysis. "CDC is working with the National Institutes of Health on a randomized controlled trial to see how effective different combinations of existing drugs are at treating gonorrhea," says Bolan. "We hope to have findings of the trial by next year."
Resistance testing key
Action must take place at all levels of government, as well as public and private research and development entities, to prevent untreatable gonorrhea, says Bolan. One important piece of that response is the need for state health departments and other public and private labs to maintain or re-build the ability to culture and test for resistance, she states. If testing cannot be performed locally, departments should partner with labs that can perform resistance testing, notes Bolan.
The CDC is working with states to build culture capacity through a multi-step process, report Bolan. The first step involves identification of which states have capacity to perform gonorrhea culture. The CDC has worked with the Association of Public Health Laboratories in conducting a survey to identify those sites. Survey findings indicate that only about 5% of the gonorrhea tests performed by surveyed public health labs were culture tests, she notes.
"We also are planning further investigations to find out which states have labs with culture capacity," says Bolan. "We are currently providing technical assistance to labs in areas where gonorrhea prevalence is high to help them re-establish culture capacity."
The CDC also is reaching out to clinicians via state sexually transmitted infection (STI) directors to make sure clinicians are aware of local and nearby labs that offer culture tests, says Bolan. the federal agency is working with local and state STI control programs to develop local response plans in case cephalosporin resistance emerges in their area.
In the meantime, the first priority for clinicians is to treat all cases of gonorrhea with the most effective regimen..sup.1 A 250-mg intramuscular dose of ceftriaxone is considered the most effective treatment in curing gonococcal infections at genital and extragenital sites. One gram of azithromycin also should be given orally to cover other copathogens and to provide another antimicrobial with activity against N. gonorrhoeae at a different molecular target, the current analysis states.
Bolan GA, Sparling PF, Wasserheit JN. The emerging threat of untreatable gonococcal infection. NEJM 2012; 366:485-487.
Centers for Disease Control and Prevention. Gonorrhea -- CDC Fact Sheet. Atlanta, 2011. Accessed at http://www.cdc.gov/std/Gonorrhea/STDFact-gonorrhea.htm (http://www.cdc.gov/std/Gonorrhea/STDFact-gonorrhea.htm).
Centers for Disease Control and Prevention. Sexually transmitted
diseases treatment guidelines, 2010. MMWR 2010; 59(RR 12); 1-110.
Centers for Disease Control and Prevention (CDC). Cephalosporin susceptibility among Neisseria gonorrhoeae isolates -- United States, 2000-2010. MMWR 2011; 60:873-877.
"Threat up for gonorrhea that is multi-drug resistant." Contraceptive Technology Update 1 May 2012. Health Reference Center Academic. Web. 20 Apr. 2012.
Gale Document Number: GALE|A286520714