TORONTO – Not every bug needs a drug.
That is the message many public health programs hope to deliver about responsible antibiotic use as more bacteria develop resistance to a host of medicines used in human and veterinary care.
Acquired resistance could make even common infections difficult, if not impossible to treat.
The third international conference since 1999 on this threat was held in Toronto Oct. 30-Nov. 2 where the 225 attendees agreed it is a complicated problem that needs to be turned around before some medicines lose their effectiveness.
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“When antibiotics were introduced, we really did think it was the end of the infectious disease era,” said Don Low of Mount Sinai Hospital and Ontario Public Health.
“We saw these drugs as the magic bullet (that) was going to solve a lot of our infectious disease problems and of course that wasn’t to be true. We saw a lot of misuse of antibiotics, overuse of antibiotics,” he said.
Prudent antimicrobial human and veterinary use was the theme of the event, but it was agreed no one knows the extent of the resistance problem around the world.
Still, human life expectancy has improved because of the ability to prevent and treat infections with better food, improved sanitation and use of antibiotics, said infectious disease specialist Jim Hutchinson of the Vancouver Island health authority.
“Everything pales in comparison to dealing with infections,” he said.
Before 1940, infections killed 6,000 children each year in Canada.
“We are fighting for the ability to keep our kids from dying,” he said.
At the moment, about 120 children die of infection each year.
Antimicrobials also improved life on the farm where an array of treatments were available to combat bacterial infections as well as prevent disease and promote growth.
However, many classes of antibiotics used in humans are also used in animals, including some of those considered by the World Health Organization to be critically important for humans.
There is a push to make these animal drugs only available with a veterinarian’s prescription to control their use and slow the potential to pass on resistance between species.
“This puts a lot of emphasis on the vet as a steward and we need to be aware of the veterinary profession living up to that,” said Scott McEwan of the University of Guelph.
The alarm was first sounded in the 1960s when salmonella showed resistance to certain drugs in the United Kingdom.
A further crisis emerged when bacteria showed resistance to powerful drugs like avoparcin and vancomycin in 1990. This precipitated a ban on antimicrobials for growth promotion in the EU.
“The countries that have a lot of agriculture do tend to have proportionately more use of antimicrobials in food animals than humans,” said Richard Reid-Smith, veterinary epidemiologist with the Public Health Agency of Canada.
Data collection an issue
Some countries do a better job of monitoring use. Denmark and Sweden have fairly sophisticated information because livestock medications are available by prescription only and the data is reported.
However, most countries do not do that and there are few standard operating procedures on how to collect this information.
Most on-farm record keeping systems are not designed for antimicrobial use data collection. Few ask how much was used or how many animals were treated and for what reason, said Reid-Smith.
However, surveillance on use is necessary to track trends and potential resistance issues, said David White of the United States Food and Drug Administration.
Continued surveillance of antimicrobial use will help address problems quickly, he said.
Evolution of bacteria toward multi-resistance is unstoppable at this point and after 50 years of use, science still does not know enough.
“We have a huge brain trust across this globe and we have not made much inroad,” he said.
The problem is everywhere, including the environment, said Agriculture Canada researcher Ed Topp.
Ten years ago, the Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS) led by the Public Health Agency of Canada started to monitor livestock and poultry from the farm to the retail sector. It tested the level of bacteria and potential for resistance to certain antimicrobials considered to be of high importance in human medicine such as ceftriaxone and ciprofloxacin.
Samples did isolate salmonella, campylobacter and E. coli in beef, pork and poultry but the levels of resistance to antibiotics was generally very low.
Collecting this information on a national basis is difficult and labour intensive, said Rebecca Irwin of the Public Health Agency, which helped develop CIPARS.
On-farm information is elusive with the exception of Quebec, where all livestock medication is only available with a veterinarian’s prescription.
“The reality is we have no clear mechanism to capture use information that was valid,” she said.
There is also a threat of budget cuts and the program is not collecting samples in all the provinces.
