For Your Information: Antimicrobial Resistance
The term antimicrobial refers to both natural and synthetic substances like antibiotics and disinfectants which can kill or inhibit the growth of microorganisms. Antimicrobial Resistance (AMR) occurs when an antimicrobial substance, or agent, is no longer effective in killing or inhibiting the growth of a particular microorganism.
Antimicrobial substances are widely used in human and veterinary medicine for the treatment and prevention of microbial infections and are also used for feed efficiency and to promote growth in animals in the agri-food industry.
The probability of an organism developing resistance increases with the length of time it is exposed to an antimicrobial agent. Bacterial strains are able to develop resistance to antimicrobial agents. Resistant bacterial strains survive and reproduce, transferring resistance to future generations and possibly to other microorganisms.
For example, a common bacterium, Salmonella, is often transmitted from animals to humans through the food chain. The emergence and dissemination of resistant Salmonella is of particular concern. Direct links have been made in some instances between veterinary antimicrobial use and the development of resistance in humans.
AMR is an important public health issue worldwide. The growth and proliferation of resistant bacteria may outpace our ability to control their effect on our health.
The increasing occurrence of AMR poses a threat to our ability to fight human and animal infections, and has potentially serious public health implications. Effective antibiotics could become fewer in number. This could make treatment more challenging and may increase health care costs.
AMR is a deeply debated subject, not only in Canada, but also internationally. There are varied opinions, perceptions and approaches involved in assessing and managing this issue. It is imperative that any decisions taken by the Government of Canada in this regard are based on the most accurate interpretation of available scientific evidence from a Canadian perspective.
AMR can develop because of any one or combination of several of the following reasons:
1. Use in agri-food industries to treat specific diseases, or to prevent illness and promote growth.
- Resistant organisms can be transmitted through food, water or direct contact with animals. They may sometimes be transferred from animals to human pathogens.
- Sometimes broad-spectrum drugs are prescribed by veterinarians, when a better practise would be to wait for test results so they can target a particular organism with the most effective narrow-spectrum drug available.
- Low doses of antibiotics in feed for growth promotion may alter the gut flora by eliminating certain bacterial species. This can allow antimicrobial resistant germs to take over.
- Cross resistance can develop when animals treated with one drug develop resistance to others of the same class of drugs.
- Another cause can be attributed to importation and use of non-approved drugs or drugs used in an extra-label manner.
2. Over-use and/or inappropriate use of antibiotics in human medicine:
- Some health care professionals prescribe antibiotics to treat viral infections which do not respond to drugs for bacterial infections.
- They may also inappropriately use broad-spectrum antibiotics when a better practise would be to wait for test results to determine, and target a particular organism with the most effective narrow-spectrum drug available.
- Individuals stop taking antibiotics after symptoms are alleviated but before the entire dose is completed.
3. Use of antibacterial cleaning products such as community or household disinfectants or antiseptics and personal hygiene products.
- Industry produces and markets a number of disinfectants for hand and surface cleanliness, resulting in the frequent and unnecessary use of products that contain antimicrobials. In fact, overuse of antibacterial cleaning products in the home, community and in health care facilities may lead to increased development of resistance in common microorganisms.
4. Environmental contamination caused by the use of cleaning and disinfectant products as well as veterinary antimicrobial drugs for use in farm and veterinary practice. The following are some examples of how this occurs:
- Inappropriate disposal of antimicrobial agents may contribute to the increase of antimicrobial-resistant bacteria and the spread of AMR in the environment.
- Factory effluents, as well as industrial and private use of antimicrobial agents, sprays and pesticides, and run-off of these agents or microorganisms from farms may contaminate air, soil and water.
- Ground water contamination through urine and manure from farm animals that have been exposed to antimicrobial drugs.
Health Canada is continuing to assess potential risks and options to minimize risks and maximize benefits to Canadians and promote judicious use of antimicrobials. Here are some actions you can take:
- If you are prescribed antibiotics, ask your physician if:
- you are being treated for a viral or a bacterial infection;
- an antibiotic is beneficial to your health; and
- if there is an alternative treatment that would work.
- you are being treated for a viral or a bacterial infection;
- Always take the full dose of antibiotics for the prescribed duration for bacterial infections even if infections or symptoms disappear earlier.
- Before using over-the-counter antibiotics, consult with your physician/pharmacist.
- Limit the use of products that claim to fight bacteria or are labelled as antimicrobial. Plain soap and water or a mild bleach solution is usually adequate for cleaning your home.
- Dispose of unused or outdated drugs in toxic waste drives or return them to the pharmacy - do not flush them down the waste system.
- Do not consume milk, cheese, poultry and other meats that have been contaminated at source, or that have not been prepared from properly pasteurized products
If you handle livestock:
- Ensure that your farm management practices contribute to a clean and safe environment.
- Practice improved hygienic conditions on the farm to avoid the use of antibiotics.
- Using antimicrobials in animal feed may not be necessary to improve the health of livestock. Make sure it is clear to you what antimicrobials are in your feed formulation and why they are there. It is not clear from the scientific literature that all in-feed antimicrobials are efficacious in today's modern livestock-rearing facilities.
- Follow specific label instructions for animal medications; use drugs only as necessary for the animals and treatments that are specified.
Health Canada, while increasing educational and outreach activities on the AMR issue, is also spearheading a variety of activities including research, surveillance and policy development, as follows:
- dedicated staff for AMR policy development within the Veterinary Drugs Directorate (VDD);
- VDD chairs and coordinates the interdepartmental AMR policy committee comprising of representatives from Health Canada, the Canadian Food Inspection Agency, Environment Canada and the Department of Fisheries and Oceans.
With multi-stakeholder groups:
- created and supported the Advisory Committee on Animal Uses of Antimicrobials and Impact on Resistance and Human Health;
- held consultation meetings with stakeholders on risk management options to address the human health risks associated with AMR;
- relies on expert scientific advice relating to the assessment of risks and benefits of using antimicrobial agents in food-producing animals; and
- provides financial support for the activities of the Canadian Committee on Antibiotic Resistance (CCAR).
- worked with federal and provincial partners and other interested stakeholders to finance the development of the Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS) being led by Health Canada's Guelph Lab. This surveillance system was established to monitor trends in the development of AMR and to collect antimicrobial use information from human and animal sources. The first annual CIPARS report was released in March 2004.
- Health Canada provides expertise to, and shares information with a number of organizations including the FAO (CODEX Committee on Residues of Veterinary Drugs in Food), and with the Center for Veterinary Medicine (Food and Drug Administration in the US);
- Health Canada's VDD represents the Government of Canada on the International Cooperation on Harmonization of Technical Requirement for Registration of Veterinary Medical Products (VICH) working groups on a variety of issues, including AMR. The VICH Expert Working Group on Antimicrobial Resistance has finalized work on Guideline 27, the guidance document, Pre-approval Information for Registration of New Veterinary Medicinal Products for Food-producing Animals with Respect to Antimicrobial Resistance.
In addition, several research projects are being undertaken to assess the association between antimicrobial use and resistance. The results of these assessments will enable the evaluation of resistance and the potential impact on human health. This will help us to gain more knowledge, as well as the ability to develop rapid diagnostic tests and new products for the specified length of time.
Research is underway and knowledge is increasing. As it becomes available, we will continue to post new information about AMR and our policies to address this issue on our Web site:
Health Canada is working to make public participation part of policy development related to public health issues such as AMR. If you would like to comment or participate, please comment via our E-mail: firstname.lastname@example.org.
Health Canada contact information:
Veterinary Drugs Directorate
Health Products and Food Branch
Holland Cross Complex, Ground Floor
14 - 11 Holland Avenue
Ottawa, Ontario. K1A 0K9
Address Locator - 3000A
General Information Number : (613) 954-5687
Fax : (613) 957-3861
Effluents: waste that is released in water from factories and processing plants
Extra-label drug use: when drugs are used for purposes other than which they were approved
Gut flora: microorganisms (including bacteria species) that are normally found in the intestinal tract of animals or humans
Microorganism: for purposes of this fact sheet, the definition includes: bacteria, yeast, protozoa, algae and virus
Pathogen: an agent that causes disease Broad-spectrum: drugs that treat a variety of micro-organisms
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