Antimicrobial Resistance and the Veterinary Clinic


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How antimicrobial resistance can threaten animal and human health.

Antimicrobial resistance is not just a human problem. It’s an increasing threat to both humans and domestic animals. Resistance to antibiotics is no longer a vague future threat but a reality for many clinicians, said Matthew Kornya, BSc, DVM. “In many veterinary hospitals worldwide, it is expected that bacteria will be resistant to one or multiple classes of antibiotic, and multi or pan drug-resistant species are increasingly encountered. In all species, the emergence of these pathogens means that not only morbidity but mortality from bacterial infections are increasingly recognized.”

Animals diagnosed with resistant bacterial infections may need to be treated with more expensive drugs (i.e., meropenem, linezolid) or other with more side effects (e.g., chloramphenicol, amikacin), said Dr. Kornya. They may be unable to undergo planned procedures or need surgical implants removed. In the worst-case scenarios, infected animals may die of their disease. “This situation is replicated in human medicine as well.”

Antimicrobial Stewardship Guidelines

To address this issue head-on, the American Association of Feline Practitioners (AAFP) and the American Animal Hospital Association announced this summer that they have published joint recommendations for antimicrobial stewardship.

The 2022 AAFP/AAHA Antimicrobial Stewardship Guidelines present evidence-guided strategies that veterinarians and their teams can use in choosing appropriate antimicrobial therapy to best serve their patients and minimize the development of antimicrobial resistance.

“This effort is critical to ensure we continue to have drugs that are effective against bacterial infections,” said Erin Frey, DVM, MPH, DACVPM, coauthor and task force chair of the guidelines. “Bacterial pathogens will always find ways to resist antibiotics, but overuse of antibiotics or using them when it’s not necessary expedites this process, ultimately leaving us with bacteria that are impervious to treatment. The result is a scenario in which we don’t have the tools to treat life-threatening bacterial infections because the available antibiotics are no longer effective.”

Antimicrobial resistance is one of the most urgent ongoing threats to public health of our time, and it impacts both humans and animals, AAHA said in comments given to Vet-Advantage. Resistance is a natural process in pathogens like bacteria, but when antimicrobial drugs are misused or overused, resistance can develop faster. “Once that happens, we get pathogens that can no longer be treated using certain drugs and even pathogens that are resistant to multiple drugs. This means physicians and veterinarians need to go to less optimal drugs to treat serious infections – drugs that may have more side effects or are last lines of defense.”

And for some infections, we may be running out of options to treat them at all, AAHA noted. A recent Lancet study that looked at global data from 2019 found that nearly 5 million human deaths were associated with antimicrobial resistance in some way.

“And while we don’t have a lot of data on the prevalence of resistant infections in companion animals, we know they happen, and we know that we have to do everything we can to slow the development of antimicrobial resistance and preserve the effectiveness of our drugs,” AAHA said. “That’s why it was so important to create this guideline with the AAFP. We’ve provided a high-level resource for veterinarians that includes actionable guidance.”

The guidelines offer a practical approach for veterinary teams that emphasizes making decisions that optimize patient outcomes and ensure that antibiotics are used only when necessary to treat infections, according to a release. The top tenets of the guidelines include:

  • Practice good preventive medicine, monitor health routinely, and keep vaccinations updated.
  • Teach clients about good animal care practices and hygiene.
  • Use other alternatives to oral antibiotics such as bathing, sprays, or ointments.
  • Consider “watchful waiting” to observe whether a condition truly needs antibiotics or if patients can clear it on their own.
  • Use diagnostic testing to determine if an infection is bacterial and would respond to antibiotics.

One of the most important points repeatedly highlighted in these guidelines is the need to carefully decide if antibiotics are warranted in a specific situation, said Dr. Kornya, a member of the task force which created the AAFP/AAHA Antimicrobial Stewardship Guidelines. Avoiding the use of antibiotics “just in case,” as a substitute for proper sterile technique, or in animals with vague signs of disease that do not specifically warrant antimicrobial therapy is crucial to judicious use. “Remembering that the presence of bacterial in or on an animal does not imply the need for antimicrobial therapy,” Dr. Kornya said. “The overuse of antimicrobials or of excessively high generation or board spectrum antibiotics can be a primary driver of resistance.”

Another important item in the guidelines is the use of cytology, culture and sensitivity results, and principles of best practice whenever possible to guide antimicrobial therapy. “This means choosing antimicrobials carefully based on what will reach therapeutic concentrations in a given location, picking the drug carefully based on the suspected organism, and then adjusting or narrowing the regimen based on sensitivity results.”

AAHA highlighted several parts of the Guidelines worth mentioning for distributor reps in conversations with their veterinary clinics:

  • Watchful waiting or delayed prescribing. “This means that if a condition is likely to resolve on its own or may not be bacterial, rather than prescribing an antibiotic, a plan for close observation and follow-up is implemented, along with other therapeutic treatments to ensure the animal is comfortable,” AAHA said. “Regular reassessments of the patient and treatment plan help to determine if antibiotics become necessary. This is really vital to preventing the over-prescription of antibiotics for conditions that will clear on their own.”
  • There are conditions where antimicrobials are commonly prescribed but are not usually caused by pathogenic bacterial infections. “Pancreatitis is a good example of this. While there can certainly be cases where antimicrobials are warranted, in most cases, pancreatitis is not associated with bacterial infections.”
  • Acute diarrhea cases – those dietary indiscretion dogs – are also generally self-limiting or not associated with pathogenic bacteria and in many cases, don’t need antibiotics. “In fact, prescribing antibiotics in these situations, where supportive care resolves the condition, can lead to further imbalances in the gut microbiome.”


Vet giving dog a shot representative of antimicrobial resistance.
Veterinarians must carefully decide if antibiotics are warranted in a specific situation.

Safeguarding antibiotics

Antimicrobial resistance is a complex issue that requires the cooperation of human, veterinary, and public health professionals to address fully, AAHA said. “But veterinarians are really well-placed to take actions that can preserve antimicrobials. We work at the intersection of human and animal health, and we’re highly involved in not only caring for animal health but also in providing a lot of public education about diseases and how and when to give medications properly.”

And there are a lot of strategies that veterinarians can adopt in daily practice to safeguard antimicrobial drugs, including making sure that therapeutic alternatives are considered before and in conjunction with antimicrobial treatments, preventing and correcting risk factors for infections, and recognizing that antimicrobials are not needed for surgeries with appropriate sterile techniques. These are all things that veterinarians do in practice, but the guidelines help practitioners be more proactive and systematic about stewardship.

Veterinarians are responsible for determining not only the correct antibiotic choice and duration of therapy but deciding whether antibiotics are required at all. “Restricting antibiotic use to only those animals who require them, using the shortest courses needed, and using antibiotics with narrow spectrums is crucial to reducing resistance in animals,” Dr. Kornya said. “As many bacteria are present in the environment and may be spread between humans and animals, restricting the overuse of antibiotics in veterinary species will limit the spread of these pathogens to humans.”

Every member of the veterinary team has a role to play in antimicrobial stewardship. “While veterinarians are generally the ones making prescribing decisions, technicians have an important job to do in terms of client coaching and education,” Dr. Kornya said. Direction on how to administer medications appropriately, the importance of when to start and stop medications, and what would trigger a re-evaluation are important to proper owner compliance. The front desk and reception teams need to recognize when animals need to present for infectious disease and what should trigger a discussion on antimicrobial use. Judicious antimicrobial use is a part of clinic culture, and establishing a practice atmosphere that respects antimicrobials and prioritizes their proper use is everyone’s responsibility.

One aspect of antimicrobial stewardship that often gets missed is the important roles that preventive care, proper animal husbandry, and hygiene play in reducing the need for antimicrobials. This is an area of communication where technicians and other support staff “can really shine,” AAHA said. “If we can educate clients on preventive care, like giving all required vaccines based on an animal’s lifestyle and risk factors, and proper animal care, like keeping pets in clean and safe surroundings and feeding proper diets, this will help prevent some conditions from occurring in the first place.”

Also, AAHA noted that diagnosing and treating underlying conditions like allergies that contribute to recurrent skin and ear infections and focusing on topicals rather than systemic medications can help reduce antimicrobial use. These strategies require taking a different approach to cases and educating clients on why we can’t just send home antibiotics every time. Because many clients expect this, it takes time and effort to correct these assumptions.

“These are education and communication–heavy strategies that need the entire veterinary team to be delivering consistent messages to clients in order to be successful.”

The guidelines are available at:


Photo credit: POGODINA

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