The terms "antimicrobials" or "antimicrobial agents" simply refer to all types of natural and synthetic drugs which may kill or slow down the growth of microorganisms. These include antibiotics, anti-fungals, and household disinfectants. Antimicrobial agents are widely used for the treatment and prevention of human and animal diseases, and in the agriculture industry they are also used to promote growth.
Antimicrobial Resistance (AMR) occurs when a specific antimicrobial drug is ineffective in killing or slowing down the growth of a targeted microorganism. Development of resistance stops or reduces the effectiveness of antimicrobial agents intended to treat human/animal infections caused by microbial pathogens. The emergence of AMR threatens our ability to fight human and animal diseases with potentially serious public health implications. This could narrow the line of defense against bacterial infections to only a few antibiotics and increase health care costs.
Cross-resistance to an antimicrobial drug may develop when bacteria associated with animals treated with one drug, develop resistance to other drugs of the same family.
The association between the use of household disinfectants/antiseptics that contain antibacterial agents and the development of AMR has been widely reported. Widespread use may lead to increased emergence of resistance in microorganisms. Resistance may develop not only against the disinfectants, but cross-resistance to antimicrobials used in human medicine may also appear.
There have been recent reports of antimicrobial-resistant bacteria in or on some meat but little is known about the extent of any such contamination. The National Integrated Surveillance System for Antimicrobial Resistance being developed by Health Canada's Laboratory for Food-borne Zoonoses will monitor the development of antimicrobial resistance in zoonotic pathogens. Information from these surveillance and research activities is crucial to dealing with the possible spread of antimicrobial resistant bacteria to humans through the food supply.
The use of antimicrobial drugs in agriculture is a contributing factor in the emergence of resistant pathogenic bacteria. However, there are other significant factors, such as the overuse and inappropriate use of antibiotics in human medicine.
Antimicrobials are prescribed and used therapeutically for the treatment of animal diseases. Antimicrobials are also added to the feed of food-producing animals to promote growth, to increase feed efficiency, and to prevent infections.
A fundamental knowledge gap associated with the AMR issue is the lack of appropriate surveillance data. For this reason, Health Canada's Laboratory for Food-borne Zoonoses (LFZ) is working to develop a national integrated surveillance system to track antimicrobial use and the spread of AMR in agri-food and aquaculture. Preliminary steps have been undertaken to develop the necessary infrastructure for surveillance. Health Canada's Veterinary Drugs Directorate (VDD), the Bureau of Microbial Hazards and the Bureau of Chemical Safety of the Food Directorate, as well as the Laboratory for Food-borne Zoonoses are working together undertaking research and surveillance activities.
In Canada, the regulation of agricultural antimicrobials is the shared responsibility of Health Canada's Veterinary Drugs Directorate (VDD) and the Pest Management Regulatory Agency (PMRA). In turn, the Feeds Section of the Canadian Food Inspection Agency (CFIA) ensures compliance of the manufacturing and sale of livestock feeds medicated with these antimicrobials.
The issue of antimicrobial resistance, and the development of an evidence-based and comprehensive regulatory policy on the same is considered one of the highest priorities for the Veterinary Drugs Directorate of Health Canada.
The 1997 consensus conference on Controlling Antimicrobial Resistance: An Integrated Action Plan for Canadians, led to the establishment in 1999 of The Advisory Committee on Animal Uses of Antimicrobials and Impact on Resistance and Human Health. On June 28, 2002, the Committee submitted its final report to Health Canada's Veterinary Drugs Directorate (VDD). The Committee's role was to provide advice and assistance to Health Canada in the development of policy options related to animal uses of antimicrobial agents. In addition to the financial support and secretariat services provided to this Committee, VDD has been spearheading a variety of other activities aimed at developing a strategic policy framework on AMR. Some of these initiatives are:
Due to the complexity of the issue it was essential that we establish the capacity required to address AMR. We now have the specific expertise and competencies in place. We have established an infrastructure to collect new data that will be essential to the development of AMR policies and action plans. Health Canada's Veterinary Drugs Directorate (VDD) is leading the federal interdepartmental efforts on both the science and policy aspects of Antimicrobial Resistance and has carefully reviewed comments received from stakeholders on the final Report of the Advisory Committee on Animal Uses of Antimicrobials and Impact on Resistance and Human Health. VDD's proposed response to the 38 recommendations contained in this Report was released in December 2002. Prior to making final decisions on the implementation of any of the recommendations put forward by the Advisory Committee,VDD is planning to hold a consultation process early in 2003 to ensure that stakeholders views are taken into consideration.
The use of antimicrobial growth promotants (AGPs) in food-producing animals and the possible contribution to resistance in human pathogens is a subject of intense international debate within the scientific community and in the animal health industry. The Veterinary Drugs Directorate of Health Canada is responsible for the approval of veterinary antimicrobials in Canada and is supporting surveillance activities to evaluate possible public health impacts of the use of AGPs. Evidence from the surveillance data is currently being collected and analyzed and will be crucial in the development of new policies and approaches.
Health Canada is aware that the use of four antimicrobials to promote growth (tylosin, spiramycin, bacitracin, and virginiamycin) in farm animal production has been banned in the European Union. These AGPs were banned for this purpose because of their structural similarity to antimicrobial drugs used in human medicine. Other countries, including Canada are reviewing available data and considering similar approaches.
Antibiotics remain the most powerful weapons against disease-causing bacteria in veterinary and human medicine. They are also being used to promote growth in animals. Researchers are studying a number of alternatives to antimicrobial uses in food-producing animals.
AMR is recognized as a global public health issue requiring urgent and concerted action by individuals, governments, physicians, veterinarians, farmers, pharmaceutical industries, as well as national and international public health organizations. You can take some of the following precautions:
microorganisms that can be killed or stopped from growing by antibiotics
alteration or change in the genetic material