Where are we at with antimicrobial resistance?

Vet Advice with Dr. Ron Clarke

Where are we at with antimicrobial resistance?

Antimicrobial resistance (AMR), often incorrectly labelled antibiotic resistance, has been the subject of immeasurable media attention through the past three decades. It’s a relentless rabble of potential health threats, what and who is to blame, and where do we go from here. AMR has spawned at least two generations, maybe three, of academic scrutiny, dissection, review and examination.

Opinions and problem-solving around AMR issues constantly shifts between paranoia and scientific reason. Concrete efforts to find lasting solutions to difficult problems seem to be going hopelessly astray. Take, for example, a 1999 article by Dr. David Price in Canadian Cattlemen trying to summarize what the issues around AMR really are measured against the recent press release from Agriculture and Agri-Food Canada with a headline stating: “New study finds antibiotic use in cattle not related to antimicrobial resistance in humans.”

As incredulous as this storyline released by Agriculture and Agri-Food Canada on March 5, 2020, may seem, I can only hope scientific scrutiny may offer a clearer description of what the study actually revealed. A sharper explanation of matters such as “phylogenetic relatedness” and “AMR phenotypes across the one-health continuum” is necessary. If not, the credibility of well designed and executed studies and a clearer understanding of very difficult topics will remain seriously flawed. Only one family of bacteria, Enterococcus sp., was subject to study. Although this particular family of bacteria is an important cause of infections in humans, it is much less important in cattle. Many important zoonotic infections were not part of the study or even mentioned (e.g. E. coli, campylobacter, salmonella, C. difficile, streptococcus). The role of a competent immune system is missing, as is the environmental potential of resistance transfer within a huge population of resident bacteria in soil and water that ultimately find their way into the AMR story and the One-Health continuum.

In 1999, Dr. Price stated very clearly that while abandoning low-level use of antimicrobials in finishing beef might improve beef’s image, resistant bacteria remained the real issue. Resistant bacteria do not evolve through the use of sub-therapeutic levels of antimicrobials in food-producing animals. To this end, agriculture had become the scapegoat when, in effect, AMR happens because of antimicrobial overuse and random mutation of bacteria in humans. New research seems to support this theory. Twenty years ago, Price postulated that bacteria resistant to animal antimicrobials that somehow develop resistance to human antimicrobials defy all evidence. Furthermore, it has not occurred in 50 years of commercial antimicrobial existence.

The harsh reality endured. Resistance to human antimicrobials arises through overuse in humans and much of that comes about because humans demand their use — needed or not.

Between 1955 and 1989, the FDA, the National Institute of Health and the National Academy of Science in the U.S. tried on nine occasions to ban low-level feeding of antimicrobials. All nine attempts failed because no definite reason could be found for their exclusion. In the end, we were told science failed to prove reasons adequate enough to proceed, but the disturbing perception that resistance could be transferred between animals and humans persisted. Scientists rewrote the chapters on regulatory directives and prudent antimicrobial use. Veterinarians bought in a reality that will someday stand as a crowning point of scientific laxity.

It’s time to revisit foundational principles of problem-solving:

  • First and foremost: accurately define the problem.
  • Look at all potential causes for the problem.
  • Using astute scientific methods, identify alternatives for approaches to resolve the problem.
  • Select an approach to resolve the problem.
  • Then plan to implement best alternatives.

We need to recognize a major difference exists between problem-solving (a method) and decision-making (a process). Problem-solving is an analytical aspect of thinking. It also uses intuition in gathering facts. Decision-making, on the other hand, is more of a judgment where, after thinking, one will take an appropriate course of action.

Looking back, little has really changed in twenty years. Our approach to managing antimicrobial resistance seems locked in a vacuum. The importance of livestock’s role in dealing with a serious human issue remains unresolved.

About the author


Dr. Ron Clarke

Dr. Ron Clarke prepares this column on behalf of the Western Canadian Association of Bovine Practitioners. Suggestions for future articles can be sent to Canadian Cattlemen ([email protected]) or WCABP ([email protected]).



Stories from our other publications