Most people are aware of the dangers of antibiotics, even those who advocate them. Vets and pet owners have learned that these medications create antibiotic resistance and destroy the healthy flora in the gut.
About 10 years ago, microbiologist Thad Stanton led a USDA study. He discovered that not only does antibiotic use in pigs change the bacterial flora in the gut, but even low doses of the drug given for only two weeks also caused a drastic increase in the number of E-coli bacteria in the gut—the opposite effect they had expected.
Antibiotic resistance in dogs is a critical issue that affects both humans and animals. The warning bells about antibiotic resistance first rang in the 1970s when microbiologist Stuart Levy published studies about how the use of antibiotics in chicken feed led to antibiotic-resistant bacteria that could actually be spread to the microbiome of farmers and beyond. This information raised the ire of those in animal production and pharmaceutical companies, and so further studies were limited. Levy believed that the industry didn’t want more studies because they were upset that the data showed them to be wrong, making this a highly political issue.
What Are Antibiotics? In the 1920s, Sir Alexander Fleming accidentally discovered penicillin, which was to be the first mass-produced antibiotic. During World War II, penicillin was used to treat wounds with a risk of bacterial infection that could lead to death, saving tens of thousands of lives. In the decades since, antibiotics have become powerful, lifesaving medicines used to treat illnesses and infections caused by specific bacteria in humans and animals, including dogs. They kill bacteria but not viruses or fungus. They’re most often used to treat urinary, respiratory, and digestive infections and specific symptoms like diarrhea, ear, and sinus issues. And they’ve become very commonplace in their use.
However, as we learn more about the immune system and the microbiome, it’s becoming equally well-known that antibiotics don’t just kill the bacteria that cause infection. Antibiotics kill ALL bacteria, even beneficial bacteria in the gut that aid in digestion, produce vitamins, help in hormone production, and destroy harmful bacteria. Without these friendly bacteria, your dog can contract a long-term illness or develop chronic disease that’s hard to treat.
What Are Antibiotic-Resistant Bacteria? Antibiotic resistance happens when bacteria don’t respond to the antibiotics designed to kill them. This creates a superbug, so stronger antibiotics are produced. And even then, they don’t work on these new strains of bacteria. So bacteria are not killed, and these types of bacterial infections in dogs continue to spread. It’s the bacteria that resist the antibiotics, not the body. In 2013, the Centers For Disease Control (CDC) published a paper on the seriousness of antibiotic resistance threats.
Antibiotic resistance is considered one of the biggest public health challenges of our time. As stated by Dr. Richard S. Patton, PhD, fighting this threat is a public health priority that necessitates a collaborative global approach across sectors. Antibiotic resistance is a natural phenomenon where bacteria evolve to avoid the effects of antibiotics. Dr. Patton explains that antibiotic-resistant bacteria are doing what any species is designed to do: survive and reproduce. Just as mammals adapt to environmental changes, bacteria also engage in survival mode and become resistant to antibiotics. This concept was also echoed by the CDC in 2013, which stated that because antibiotic resistance occurs as part of a natural evolution process, it can be significantly slowed but not stopped. Therefore, new antibiotics will always be needed to keep up with resistant bacteria. Sir Alexander Fleming warned about the overuse of antibiotics as early as 1945, stating that the public would demand the drug, leading to an era of abuses. Despite knowing about antibiotic resistance for almost 50 years, antibiotics are still prescribed with little hesitation today. The World Health Organization (WHO) and the CDC are leading the way with warnings about limiting the use of antibiotics and admitting their abuse. The causes of antibiotic resistance are multifaceted: – Over-prescribing of antibiotics – Prescribing antibiotics unnecessarily or without proper bacteria testing – Prescribing antibiotics beyond the scope of what is needed – Patients who fail to finish an entire course of antibiotics, allowing remaining bacteria to become ‘superbugs’ – Overuse of antibiotics in livestock and fish farming operations – Poor infection control in hospitals and health care facilities – Poor hygiene and sanitation – Failure to develop new antibiotics In 2020, the WHO declared antimicrobial resistance one of the top 10 global public health threats facing humanity, citing misuse and overuse of antibiotics as the source of drug-resistant pathogens. The world urgently needs to change the way it prescribes and uses antibiotics. Even if new medicines are developed, without behavior change, antibiotic resistance will remain a major threat. Where antibiotics can be bought for human or animal use without a prescription, the emergence and spread of resistance are made worse. A 2015 report, ‘The Antibiotic Resistance Crisis,’ states that the crisis has been attributed to the overuse and misuse of these medications, as well as a lack of new drug development by the pharmaceutical industry due to reduced economic incentives and challenging regulatory requirements.
According to reports and data from the CDC and FDA, since 1985, the number of new antibiotics approved for use has steadily decreased while approval for cancer drugs has risen. In 2017, the cost of developing an antibiotic was about $1.5 billion with a return on investment of only $46 million. In contrast, antibiotics are generally low cost, priced at $1,000 to $3,000 for a course, which is considerably less than chemotherapy that can cost tens of thousands of dollars. A drug for treating a neuromuscular disease could be valued as high as $1 billion.
It’s known for 50 years that antibiotic use in livestock increases the risk of antibiotic resistance in humans. Bacteria are passed through animal waste from large-scale farms and infect farmers and workers who come in contact with them. Bacteria also travels through fish farming operations and wastewater from antibiotic manufacturing, hospitals, and municipalities as antibiotic pollution. Humans and animals excrete antibiotics and bacteria in feces and urine, passing on genes to other animals and microbes in the environment. Antibiotic resistance affects dogs as well as people and other animals. Several studies show that drug-resistant bacterial infections like MRSA are on the rise in dogs. In 2010, researchers at Canada’s University of Guelph found that MRSA is an emerging pathogen in dogs with risk factors similar to those in humans. There’s a suggestion dogs may share antibiotic resistance with the people they live with. Over-prescribing of antibiotics is widespread. The American Veterinary Medical Association’s Task Force For Antimicrobial Stewardship in Companion Animals said it seems likely that unnecessary use of antibiotics in companion animal settings is close to 50%. A problem like antibiotic-resistant UTI in dogs is widespread. Misuse happens when the wrong antibiotic is chosen or a stronger or broader-spectrum antibiotic is given when a narrower treatment would do. Often antibiotics are prescribed without test results. Some owners may pressure vets for a prescription or an antibiotic is given to rule out the cause of illness or just in case. This has brought into question the spread of antibiotic resistance between companion animals and humans. In a 2020 study, researchers looked at 303 dogs and cats for a year in three European countries.Studies have confirmed high usage of broad-spectrum antimicrobials, often not in line with European guidelines. While antibiotic use in pets is lower than in farming, there is a significant use of critically important antimicrobials, meaning stronger antibiotics. It has been concluded that the issue is not just the quantity but the quality of antimicrobials used. From a One-Health perspective, companion animals might transmit resistance genes or resistant bacteria to humans. Country-level data shows higher resistance in pets follows trends of higher antimicrobial use.
Antibiotic-resistant bacteria in food is another concern. In August 2021, the American Kennel Club questioned why many meat products contain antibiotic-resistant bacteria. The answer lies in the food-production system, where many animals for consumption are given antibiotics, leading to bacterial mutation and resistance. This is not limited to animals raised for dog food. Approximately 80% of antibiotics in the US are used in livestock. Researcher Dr. Ana Freitas suggests authorities should review the production circuit of dog food, from raw material selection to manufacturing and hygiene practices.
Is there an alternative to antibiotics? Ceasing their use in farming operations could make a significant difference. In 2003, the WHO reported on Denmark’s cessation of antibiotic use on industrial farms, noting no negative impact on food animal production. The industry’s productivity and output have increased. The WHO also stated that the non-therapeutic use of antimicrobials should not replace good animal health management.
For decades, scientific reports have advocated for more research into alternatives to antibiotic use. In a 2020 study, CH Wang et al. explored options, stating an emergent need for new classes of antibiotics and novel treatment approaches, including repurposing existing drugs or preclinical compounds and expanded combination therapies. They also advise monitoring the prescribing and use of antibiotics to delay the spread of antibiotic-resistant organisms. Microbiologist Stanton, in his 2013 report, called for innovative and bold solutions to slow resistance to antibiotics and speed the development of new antibacterials, emphasizing the need for judicious antibiotic use.
The Levy studies from the 1970s revealed that farm animals given antibiotics not only developed resistance themselves but also contributed to antibiotic resistance in humans working on those farms. This resistance can persist for years, as it is passed down through generations via mothers to their offspring. Additionally, the spread of resistant bacteria through feces and manure can affect other farms, animals, and people.
The same risk of antibiotic resistance exists in our yards, parks, and dog boarding facilities. Feces can be tracked by dogs, children, and even birds, spreading resistant bacteria. Cat owners should also be aware of the risk when their cats use the litter box and then access food preparation areas.
Dog owners can take steps to minimize or eliminate the use of antibiotics. Ensuring a dog’s immune system is healthy through a whole food, meat-based diet and the use of pre- and probiotics can support the dog’s microbiome. In cases of mild infection, natural antibiotic alternatives can help the dog fight off the infection without resorting to antibiotics.
Antibiotics should be reserved for serious situations where no other treatment is effective. If a vet prescribes antibiotics, it’s crucial to ask if they are truly necessary and to explore alternatives that do not harm the dog’s microbiome or contribute to antibiotic resistance.
References:
1. Levy, SB, et al. Changes in Intestinal Flora of Farm Personnel after Introduction of a Tetracycline-Supplemented Feed on a Farm. N Engl J Med. 295:583–588. 1976.
2. Levy, S, et al. Spread of antibiotic-resistant plasmids from chicken to chicken and from chicken to man. Nature. 260, 40–42. 1976.
3. Centers for Disease Control and Prevention. Antibiotic resistance threats in the United States, 2013. U.S. Dept of Health and Human Services. CDC. 2013.
5. Patton PhD, Richard S. Ruined By Excess, Perfected By Lack. The Paradox Of Pet Nutrition. DN Publishing. 2017.
7. Ventola CL. The antibiotic resistance crisis: part 1: causes and threats. P&T. 40(4):277-83. Apr 2015.
8. WHO. Antimicrobial resistance fact sheet.
9. Adrian Towse, et al. Time for a change in how new antibiotics are reimbursed: Development of an insurance framework for funding new antibiotics based on a policy of risk mitigation, Health Policy. Volume 121, Issue 10, 2017, Pages 1025-1030.
10. Faires MC, Traverse M, Tater KC, Pearl DL, Weese JS. Methicillin-resistant and -susceptible Staphylococcus aureus infections in dogs. Emerg Infect Dis. 2010;16(1):69-75.
11. Bender, JB. The AVMA Task Force for Antimicrobial Stewardship in Companion Animal Practice responds. JAVMA. 246(7):727-8, April 2015.
12. Joosten P, et al. Antimicrobial Usage and Resistance in Companion Animals: A Cross-Sectional Study in Three European Countries.
Raw dog food has been linked to the rise in antibiotic-resistant bacteria, as discussed by Mary Robins in her article for Antibiotics (Basel). Published on February 13, 2020, the study highlights the potential dangers of feeding raw food to dogs.
The issue of antibiotic resistance is not new, and organizations like The Pew Charitable Trusts have been advocating for measures to combat it. Denmark’s ban on growth-promoting antibiotics in food animals, as mentioned by The Pew Campaign on Human Health and Industrial Farming, is an example of such measures.
Researchers are actively exploring alternative therapies to defeat antibiotic-resistant bacteria. Wang CH, et al., in their study published in Int J Mol Sci, suggest exploring alternative therapies for a post-antibiotic era.
Stanton TB emphasizes the need for research into antibiotic alternatives in his article in Science & Society. He calls for more focus on this critical area to address the growing problem of antibiotic resistance.
Additional research indicates that antibiotic resistance in pets is an increasing problem, as reported by the Center for Infectious Disease Research and Policy in August 2016.
Casaburi G, Duar RM, and their colleagues found that early-life gut microbiome modulation can reduce the abundance of antibiotic-resistant bacteria, as published in Antimicrob Resist Infect Control.
Pamer EG discusses the importance of resurrecting the intestinal microbiota to combat antibiotic-resistant pathogens in his study published in Science.
The United Nations has also recognized the threat of antimicrobial resistance, as documented in the Bull World Health Organ.
Finally, Panwar, R.B., Sequeira, R.P., & Clarke, T.B., in their research published in Genes Immun, discuss the role of microbiota-mediated protection against antibiotic-resistant pathogens.
