Of Microbes and Men
by Dr. Janice Mitchell
MRSA. This acronym strikes fear in the hearts of physicians…of both the M.D and D.V.M. kind. Methicillin Resistant Staphylococcus Aureus is one of many micrororganisms that are no longer controlled by our good old standard antibiotics, or antimicrobials, and the cost to lives and health care systems is ever increasing. It is for this reason that the World Health Organization has taken steps to initiate more judicious, controlled and proper use of the current antimicrobials that we have. The World Health Organization is working closely with the Food and Agriculture Organization of the United Nations and the World Organization for Animal Health in a ‘One Health’ approach to promote best practices to avoid the emergence and spread of antibiotic resistance, including optimal use of antibiotics in both humans and animals. The College of Veterinarians of Ontario encourages its licenced members to be aware that responsible use of antimicrobial drugs is crucial for preserving their efficacy and, as of December 1, 2018, these drugs will only be sold if there is a prescription from a veterinarian.
Antimicrobial resistance (AMR) threatens the effective prevention and treatment of an ever-increasing range of infections caused by bacteria, parasites, viruses and fungi. Without effective antibiotics, the success of major surgery and cancer chemotherapy would be compromised. Patients with infections caused by drug-resistant bacteria are at increased risk of worse clinical outcomes and death, and consume more health-care resources than patients infected with non-resistant strains of the same bacteria. Some bacteria known with resistance concerns include the previously mentioned staphylococcus aureus, e. coli, and klebsiella pneumoniae. In 2016, 490,000 people developed multi-drug resistant TB globally, and drug resistance is starting to complicate the fight against HIV and malaria. In the viral department, virtually all influenza A viruses circulating in humans were resistant to one category of antiviral drugs.
Antimicrobial resistance happens when microorganisms (such as bacteria, fungi, viruses and parasites) change when they are exposed to antimicrobial drugs (such as antibiotics, antifungals, antivirals, antimalarials and anthelmintics). Microorganisms that develop antimicrobial resistance are sometimes referred to as “superbugs.” As a result, the medicines become ineffective and infections persist in the body, increasing the risk of spread to others.
Antimicrobial resistance occurs naturally over time, usually through genetic changes.
However, the misuse and overuse of antimicrobials is accelerating this process. In many places, antibiotics are overused and misused in people and animals, and often given without professional oversight. Examples of misuse include when they are taken by people with viral infections like colds and flu, and when they are given as growth promoters in animals or used to prevent diseases in healthy animals.
As a result, the increase in antimicrobial resistance has placed an even higher societal duty on the veterinary profession to act as stewards with respect to the prudent and responsible use of antimicrobial drugs. As part of good stewardship, a veterinarian must only prescribe antimicrobial drugs within a veterinarian-client-patient relationship and where strong clinical evidence demonstrates medical need. What does responsible use of antimicrobials look like? Quite simply, it’s: only by prescription; only when necessary, and only at a dosage needed based on evidence. And although it seems pretty obvious for companion and farm animals to receive a prescription for antibiotics from their veterinarian, prescriptions are now required for those involved in aquaculture (both farmed and pet fish) and apiculture industries.
The College of Veterinarians of Ontario lists veterinarians who practice on both fish and bees.
It is now 90 years since the discovery of penicillin by Alexander Fleming, one of the greatest advances in therapeutic medicine. Bacteria have existed from very early in the history of life on Earth (there are convincing arguments that bacteria have been present since early Precambrian time, about 3.5 billion years ago). It is important to know that these little organisms will be ever present and thus it is important for humans to guard what tools we do have in the battle against bacteria induced disease . In the case of the “superbugs,” we don’t need another hero.
EDITOR’S NOTE: Dr. Janice Mitchell is a veterinarian at Island Animal Hospital and Little Current Veterinary Services.
