U.S. health officials have identified a cluster of gonorrhea infections that show sharply increased resistance to the last effective treatment available for the country's second most commonly reported infectious disease.
The findings from a cluster of Hawaii cases, presented Wednesday at a conference on prevention of sexually transmitted diseases, represent the first cluster of cases in the United States that have shown such decreased susceptibility to the double-antibiotic combination used when other drugs have failed. If the bacteria continue to develop resistance, that end-of-the-line therapy ultimately will fail, and an estimated 800,000 Americans a year could face untreatable gonorrhea and the serious health problems it causes, health officials said.
This latest news about antibiotic resistance came as world leaders gathered at an unusual meeting at the United Nations to address the rising threat posed by superbugs, microbes that can’t be stopped with drugs. Leaders adopted a joint declaration committing them to address the root causes of antimicrobial resistance, especially in human health, animal health and agriculture.
Nations called for better use of existing tools to prevent infections in humans and animals, including farmed fish. Norway's prime minister spoke about how her country has been vaccinating every single "baby salmon, just like small kids," and as a result, has cut antibiotic use in one of its principal foods and exports to virtually zero.
In the United States, drug-resistant gonorrhea already is one of the country's three most urgent superbug threats, according to the Centers for Disease Control and Prevention. In each case, as with other diseases such as pneumonia and tuberculosis, overexposure to antibiotics has allowed the particular germ to more rapidly develop resistance.
CDC warned this summer that evidence of gonorrhea's diminished vulnerability to one of the last-resort drugs, azithromycin, was emerging nationwide. But it said the other antibiotic, ceftriaxone, was still effective.
That's why the latest findings are so distressing for health officials. It means current treatment options are in jeopardy, said Gail Bolan, director of CDC's division of STD prevention. "What's unique about this cluster now identified in Hawaii is that these strains, we've really never seen before," she said.
Laboratory tests of the gonorrhea samples collected from seven people in Honolulu in April and May showed resistance to azithromycin at "dramatically higher levels" than typically seen in the United States, according to researchers from Hawaii's state health department. Five of the seven samples also showed increased resistance to ceftriaxone.
Hawaii is on the front line for antibiotic-resistant gonorrhea, health officials say, and monitors resistance patterns closely. So the state was able to catch this cluster of cases early. Although the patients were treated successfully with the recommended two drugs, and no other cases were identified, officials are worried that the resistance pattern and cluster indicate the strain was able to spread.
Many people don't actually know they're infected with gonorrhea because they have no symptoms. As a result, the disease goes undetected and untreated, which can cause a range of problems. Women risk chronic pelvic pain, life-threatening ectopic pregnancy and even infertility. And for both women and men, infection also increases the risk of contracting and transmitting HIV.
History has shown that gonorrhea bacteria have been able to outsmart and become resistant to a long list of antibiotics that includes penicillin, tetracycline, and fluoroquinolones. CDC has been closely monitoring early warning signs of resistance not only to azithromycin but also to cephalosporins, the class of antibiotics that includes ceftriaxone.
But officials now say there are no back-up options that are highly reliable, widely available, affordable and well tolerated. An oral antibiotic under development might offer a possible new treatment, researchers from Louisiana State University said at the CDC-sponsored conference in Atlanta. The drug was generally safe and effective in treating gonorrhea in a phase 2 clinical trial; those results will need to be confirmed in a large-scale clinical study.
The experimental drug works differently from any currently marketed antibiotic. It is a single-dose oral therapy and could be used as an alternative to a ceftriaxone injection. In the randomized controlled trial reported Wednesday, researchers treated 179 people with gonorrhea using the experimental drug alone (at two different dosages) or ceftriaxone alone. Virtually all the patients receiving the experimental drug were cured, they said. Every patient given ceftriaxone also was cured.
At the UN meeting in New York, antibiotic use in animals was a major focus. Norway long depended on antibiotics to protect farmed salmon from a bacterial fish disease, and the fish industry was concerned that "you couldn't have growth if you don't use antibiotics," Prime Minister Erna Solberg said.
But that turned out not to be the case, she said. In the late 1980s, scientists there developed an effective vaccine that has no side effects in humans. By 1994, fish farmers had made the switch from antibiotics to vaccination. For 15 years, farmers vaccinated the baby salmon by hand until better technology was developed, she said.
"We need an international ban on using antibiotics as growth improvement," she said. "To combat illness, yes, but not as growth improvement."
Participants welcomed what everyone agreed was long overdue attention to antimicrobial resistance. But several said declarations and "action plans" aren't enough without measurable goals and concrete targets.
At a fundamental level, antimicrobial resistance is a public health failure, some experts said. Governments need to accept that responsibility, stressed Joanne Liu, international president of Doctors Without Borders, which is known by its French acronym, MSF. "I am running out of options," she said. Too often, MSF doctors are treating children injured by war wounds who "end up dying from a bone infection weeks later," she said.
Martha Tellado, president and chief executive of Consumer Reports, said countries need to launch high-profile public awareness campaigns, and institutions such as hospitals need to be more transparent so consumers can be informed about drug-resistant outbreaks.
Martin Khor, executive director of the South Centre, an intergovernmental organization of developing countries, said there have been similar declarations to fight antimicrobial resistance in the past.
"For 40 years, governments have not stepped up enough to take a leadership role," he said. Developing countries need to be convinced of the seriousness of the issue, and their civil societies need to become engaged to exert pressure on elected officials. "If it comes from society, and society says to politicians, 'This is what we want you to do,' then it will create a political will," he said.