Gonorrhea is putting up increasing resistance to the last antibiotic class highly effective against it, the CDC has again warned.
The prevalence of gonorrhea resistant to the cephalosporin cefixime (Suprax) was just 0.1% in 2006 but had jumped 17-fold to 1.7% as of mid-2011, Gail A. Bolan, MD, director of sexually transmitted disease prevention at the CDC in Atlanta, and colleagues reported.
That rate is up from 1.4% in 2010, as the CDC reported last year when it first warned about cephalosporin resistance.
The CDC has typically changed gonorrhea treatment recommendations once the prevalence of resistance tops 5% in its surveillance of infections, but there aren’t any agents left to switch to, Bolan’s group wrote in a perspective article in the New England Journal of Medicine.
“It is time to sound the alarm,” they wrote. “There is much to do and the threat of untreatable gonorrhea is emerging rapidly.”
Because of resistance to other classes, the CDC currently recommends only third-generation cephalosporins for gonorrhea treatment. This class of drugs remains highly effective against most gonorrhea strains U.S. clinicians are likely to see, and should still be used, the group noted.
The most effective strategy for gonorrhea at genital and other sites, they said, is a 250 mg intramuscular dose of ceftriaxone (Rocephin) plus 1 g of the oral macrolide antibiotic azithromycin (Zithromax, Zmax), which fights gonorrhea bacteria through a different molecular target and also covers other copathogens.
Clinicians had gotten away from dual treatment with the advent of more sensitive tests for chlamydia, which often accompanies gonorrhea, Bolan noted.
“Now we feel we need to go back to dual therapy,” she said in an interview with MedPage Today.
She drew an analogy to combination therapy for tuberculosis, which has both extensively drug-resistant varieties (XDR) as well as a “totally” drug-resistant form of tuberculosis reported last month by researchers in India.
For gonorrhea, the tetracycline antibiotic doxycycline “seems less preferable,” the group added, “since gonococcal strains with decreased susceptibility to cefixime currently exhibit tetracycline resistance as well.”
Oral cefixime should be used only if ceftriaxone can’t be, they recommended. If neither will work because a patient is allergic to cephalosporins, 2 g of azithromycin is the only alternative.
Action to expand this armamentarium is necessary, Bolan’s group argued.
“Investing in rebuilding our defenses against gonococcal infections now, with involvement of the health care, public health, and research communities, is paramount if we are to control the spread and reduce the consequences of cephalosporin-resistant strains,” they wrote.
Neisseria gonorrhoeae has a track record of resistance:
- To sulfanilamide in the 1940s
- To penicillins and tetracyclines in the 1980s
- To fluoroquinolones by 2007
The patterns of resistance across the country and demographic groups for cephalosporins mirrors those seen when resistance to fluoroquinolones emerged, Bolan and colleagues noted.
The biggest increases in cephalosporin resistance were in the western United States (from 0.2% in 2006 to 3.6% in 2011) and among men who have sex with men (from 0.2% to 4.7%).
Clinicians should be vigilant for cases in which cephalosporin treatment has failed, retesting patients who show persistent or recurrent symptoms soon after treatment and reporting cases to local or state health departments.
The high-risk groups should get retesting regardless of apparent treatment success, the researchers recommended.
“Clinicians caring for men who have sex with men, especially on the West Coast or in Hawaii, should consider performing a test of cure with a culture or a nucleic acid–amplification test one week after treatment, particularly if cefixime is administered,” they wrote.
Bolan reported having no conflicts of interest to disclose.
Primary source: New England Journal of Medicine
Bolan GA, et al “The emerging threat of untreatable gonococcal infection” N Engl J Med 2012; 366: 485-487.