Moving From East to West
Cephalosporin resistance has been emerging in Japan, and moving east and west from there, for at least a decade. In 1999 physicians in Kitakyushu in southern Japan saw two men with gonorrheal infections that had not responded to the usual doses of cephalosporins or related drugs. Within two years more resistant cases emerged. A clinic in Hawaii treated a man with the standard dose of cefixime—a cephalosporin that comes in oral form—but he returned because his symptoms had not gone away. The man said he had had two sex partners who came from Japan, both women. One woman could not be found; the other woman and the man were cured only after receiving higher than usual doses of several different drugs.
Rapid international travel allowed the resistance mutation to hopscotch the globe. Sweden found its first case of the less susceptible strain in 2002. By 2005 it was in England. In 2010 Norway identified its first cases, in men who had had sex with women while traveling in the Philippines and Spain. That same year a Swedish man who contracted gonorrhea after having sex with a woman in Japan could not be cured until he received four times the standard dose of ceftriaxone, an injectable cephalosporin that doctors used because oral cefixime no longer worked. “We may now be reaching the ceftriaxone [doses] for which complete bacterial eradication ... will be impossible,” warned the physicians who treated him in a February 2011 report.
Last July Japanese researchers announced at a meeting in Canada that they had found a gonorrhea strain in a Kyoto sex worker that was “highly resistant” to both ceftriaxone “and most other antimicrobials tested.” The infection was finally controlled with intravenous antibiotics, but experts say that was a one-time fix, impractical for most clinics. In March other researchers announced a similar case in France.
“We can’t go back to older antibiotics,” says Peter Leone, who is board chair of the National Coalition of STD Directors and medical director of North Carolina’s STD prevention program. “Once resistance emerges in gonorrhea, it is there for good. Cephalosporins are all we have left.”
Uncertain What Comes Next
Efforts to control STDs may have inadvertently accelerated the spread of resistance. For years standard practice has been to quickly identify an infection, dole out the appropriate treatment and then move on to the next patient. If symptoms return, the assumption has been that the patient was reinfected. Experts now say that such patients may in fact have harbored resistant bacteria that were never killed in the first place—bacteria that the patients possibly spread to others.
Physicians would not have recognized that they were dealing with increasingly resistant bacteria, because the rapid tests most commonly used to diagnose sexual infections cannot identify resistant organisms. Instead the tests look for a DNA segment that is unique to gonorrhea, destroying the bacteria in the process. Identifying resistance requires intact living bacteria that researchers can grow in a lab dish and expose to antibiotics to see which drugs work or do not.
Routinely testing patients for resistant strains with the culture tests instead of rapid tests would be costly and time-consuming. But in the February New England Journal editorial, lead author Gail Bolan, director of the CDC’s division of STD prevention, argues that it is necessary. She also recommends retesting patients after treatment to make sure the infection is gone.
Doctors who treat sexually transmitted infections say that although such changes are sensible, they are not easy. Collecting bacterial samples for analysis requires supplies that most offices do not keep on hand, says Melanie Thompson, executive director of the AIDS Research Consortium of Atlanta, which also does STD testing. “A health care provider who suspected a resistant case would have to recognize it,” she explains, “contact the CDC or state health department to report it, go about getting the materials and then get the patient back in to give a sample.”