Drug-resistant gonorrhea spreading in Ontario
Published Tuesday, September 20, 2011 8:34PM EDT
TORONTO - A new study raises concerns about the spread of drug-resistant gonorrhea in Ontario.
A strain of gonorrhea that responds poorly to the last class of drugs available to treat the bacteria is gaining ground among the strains spreading in the province, data presented Tuesday at an infectious diseases conference in Chicago suggest.
The strain wasn't seen in the province in 2005, but by May of this year made up 11 per cent of a representative sample of gonorrhea isolates tested by the provincial laboratory, Dr. Vanessa Allen of Public Health Ontario reported at the Interscience Conference on Antimicrobial Agents and Chemotherapy.
The majority of cases that have been spotted were in men in Toronto. But the strain has been seen elsewhere in the province as well as in other parts of Canada and around the globe, said Allen, a medical microbiologist.
New approaches to treating and controlling the sexually transmitted disease need to be adopted before the bacteria outsmarts all the drugs available to treat the infection, she suggested.
"There's a very imminent threat that there will be nothing left to treat this infection with. And unless we're very careful now, I really think that we're at risk of getting there sooner rather than later."
Public Health Agency of Canada confirmed Tuesday its experts are working on revised guidelines for testing and treating gonorrhea.
"The more aggressive we can be, the more chance we have of eradicating this drug-resistant clone," Allen said in an interview from Chicago.
On Monday, the Canadian Medical Association Journal warned in an editorial that the threat of widespread multi-drug-resistant gonorrhea demands an urgent public response.
"Without action, we are heading back to the pre-antibiotic era, with an escalation in the number of deaths from other multi-resistant organisms as well as rampant gonococcal infections," said the editorial, signed by several editors including journal editor Dr. Paul Hebert.
Known as "the clap" in bygone days, gonorrhea can be challenging to control because some people who are infected don't have symptoms. Curing the infection does not provide lifetime protection, as is seen with some diseases; a person can be reinfected with gonorrhea.
The bacteria are spread by sexual contact and infection can occur in multiple sites in the body. But doctors often don't look for signs of infection in places like the throat or anus, Allen said, which contributes to the number of cases that are missed.
In women, untreated gonorrhea can cause pelvic inflammatory disease which can lead to chronic pelvic pain and infertility. Babies born to women with gonorrhea may suffer from blindness or life-threatening blood infections. The bacteria can also cause infertility in men.
If the bacteria move to the blood or joints, infection can be fatal. Infection with gonorrhea increases one's risk of being infected with HIV; and HIV-positive people with gonorrhea can transmit HIV more easily to sexual partners.
In the era of antibiotics, gonorrhea infections have been easily treated. But the bacteria have rapidly and relentlessly developed resistance to all classes of the drugs that have been used against them, forcing public health experts like Allen to contemplate what would have been unthinkable in the heyday of antibiotics -- a return to the days when gonorrhea could not be treated.
Earlier this year the U.S. Centers for Disease Control reported that an increasing proportion of gonorrhea cases need to be treated with higher-than-normal levels of the main antibiotic used, cephalosporin. That's because standard doses aren't killing off the bacteria.
Allen noted that in Japan, doctors have had to resort to using an antibiotic delivered by intramuscular injection rather than in pill form because the pill -- cefixime -- is no longer effective.
British Columbia is thinking about recommending the same approach, Dr. Richard Lester, an infectious diseases specialist at the British Columbia Centre for Disease Control, said in an interview.
Lester said the BCCDC hasn't seen cases where cefixime failed to cure gonorrhea. But when bacteria recovered from patients are tested in the lab, in some cases higher-than-standard doses of drug are needed to kill the bacteria. That's a sign of growing resistance, he said.
"We're in the worried phase, but we're still in the prevention-of-a-disaster phase, hopefully," Lester said. He noted that B.C. has increased surveillance for gonorrhea resistance.
Ontario is still using the pill form of the drug, though Allen said Public Health Ontario expects to see the same problem arise here. But she said there has been a reluctance in Canada to move to use of the injectable form of the drug.
Another factor that is contributing to the problem and complicating efforts to assess how big it is comes from an unlikely source.
Widespread adoption about a decade ago of a new rapid test for gonorrhea is actually helping to mask the extent of the problem. The test is more popular with doctors and patients; results are more available more quickly and it tests urine, thereby eliminating the need to take a painful urethral swab.
But those swabs provided agencies like Public Health Ontario with pivotal information. Swabs allow labs to grow and isolate the actual bacteria causing an infection; urine tests just tell a doctor the bacteria are present. By growing bacteria, labs can study their genetic blueprints and test bacteria to see if they are susceptible to antibiotics.
Without bacterial isolates, a doctor treating a patient with gonorrhea has no way of knowing if the drugs being prescribed will be effective against the strain causing that particular infection. And public health labs like the one at Public Health Ontario have a harder time assessing how widespread the resistance problem is.
Allen thinks part of the answer may be following the lead of Britain, where doctors ask gonorrhea patients to come back so they can be tested to see if they have been cured. That's not currently policy in Canada.
"I think that's an interesting public health strategy because then you could make sure that these drug-resistant ones are picked up sooner rather than later," she said.
Unless public health experts can figure out ways to prolong the effective lifespans of the few remaining antibiotics that can be used against gonorrhea, the problem is going to get substantially worse, Allen suggested.
If these drugs fail, she said, "there's nothing currently available commercially to give."