Options running out for gonorrhea treatment
Although there have been no documented treatment failures in the United States, untreatable gonorrhea might become a reality in this country, according to a new report from the Centers for Disease Control and Prevention (CDC).1 Time is of the essence in determining a new course of action. An international research team has just discovered a strain of gonorrhea resistant to all available antibiotics.2
The research team reported its findings at the July 2011 annual conference of the International Society for Sexually Transmitted Disease Research in Quebec City, Canada. The scientists have been able to successfully identify a heretofore-unknown variant of the bacterium that causes gonorrhea, Neisseria gonorrhoeae. By examining the new strain, now dubbed H041, investigators have been able to identify the genetic mutations responsible for the bacterium's extreme resistance to all cephalosporin-class antibiotics, the last remaining drugs still effective in treating the sexually transmitted infection (STI).
"Cephalosporins are our last line of defense for treating gonorrhea, and as far as I'm aware, no new antibiotics are in the research pipeline," says Bob Kirkcaldy, MD, MPH, medical officer in the CDC's Division of STD Prevention and author of the CDC report. "This is why CDC is calling on both public and private partners to make finding new treatment solutions a high priority."
Gonorrhea control relies heavily on antibiotics, and researchers need to identify new effective drugs or drug combinations, Kirkcaldy observes. There are existing efforts to study existing antibiotics to see if they are safe and effective for the treatment of gonorrhea, one which includes a collaboration between the National Institutes of Health and the CDC. "However, we can't predict the results of the current studies, so additional studies of drugs or drug combinations are urgently needed," says Kirkcaldy.
Public health on lookout
The CDC reports notes the highest level of resistance to cephalosporins, regardless of sexual partner, was found in the Western region of the United States, particularly Hawaii and California, as well as in men who have sex with men in all regions.
The new data outlines what state and local health departments have been seeing on the front lines: that highly untreatable gonorrhea is near, said William Smith, executive director of the Washington, DC-based National Coalition of STD Directors, in a statement following the CDC report. "There are currently no new drugs in development for this infection," said Smith. "If this last class of drugs fails, we will have no definitive treatment options for gonorrhea."
Since 1986, the CDC's Gonococcal Isolate Surveillance Project routinely has monitored gonorrhea drug susceptibility by collecting samples from men with urethral gonorrhea at STD clinics in about 30 U.S. cities. The project has been able to detect the disease's resistance to many classes of antimicrobials once recommended for treatment. Quinolone-resistant Neisseria gonorrhoeae strains are widely disseminated throughout the United States and the world, and as a result, quinolones are not recommended for the treatment of gonorrhea.
Use the latest CDC guidelines for treatment. For uncomplicated gonococcal infections of the cervix, urethra, and rectum, the recommended regimens are
- ceftriaxone 250 mg intramuscular injection in a single dose; or if not an option:
- cefixime 400 mg orally in a single dose;
- or single-dose injectable cephalosporin regimens, plus azithromycin 1g orally in a single dose OR doxycycline 100 mg orally twice a day for seven days.3
In addition, CDC officials ask that healthcare providers obtain cultures to test for decreased susceptibility from any patients with suspected or documented gonorrhea treatment failures. Clinicians also should report any suspected treatment failure to local or state public health officials within 24 hours to help ensure that any future resistance is recognized early.4
The CDC is calling for state and local health departments and other laboratories to maintain culture capacity so that antibiotic resistance testing can be quickly performed and reported. If antibiotic resistance testing cannot be performed locally, facilities should identify and partner with other labs that can perform such testing, CDC officials note. The agency asks health departments to develop local response plans and immediately notify the agency of treatment failures. Laboratories also should report isolates with decreased susceptibility to cefixime or ceftriaxone to local or state public health officials, CDC officials state.4
- Centers for Disease Control and Prevention (CDC). Cephalosporin susceptibility among Neisseria gonorrhoeae isolates United States, 2000-2010. MMWR 2011; 60:873-877.
- Ohnishi M, Unemo M, Golparian D, et al. The new superbug Neisseria gonorrhoeae makes gonorrhoea untreatable? First high-level ceftriaxone resistance worldwide and public health importance. Sex Transm Infect 2011. Doi:10.1136/sextrans-2011-050109.121.
- Centers for Disease Control and Prevention. Sexually transmitted diseases treatment guidelines, 2010. MMWR 2010; 59(RR12); 1-110.
- Centers for Disease Control and Prevention. Antibiotic Treatment of Gonorrhea. Fact sheet. Accessed at http://www.cdc.gov/nchhstp/Newsroom/docs/Antibiotic-Treatment-of-GC-fact-sheet.pdf.