August 23, 2023
A recent case report documented a multi-drug resistant infection detected in a 12-year-old girl with a brain tumor. The girl presented to the pediatric oncology department two days after her final chemotherapy treatment for vomiting, lethargy, coughing, and difficulty breathing. Upon admission, she was stable with no fever, but evidence of pneumonia was detected on chest X-rays. Blood cultures were collected, and she was started on a cocktail of antibiotics and other medications. However, six days later, her respiratory function declined, requiring non-invasive ventilatory support and a change in her antibiotic regimen. The following day, her condition worsened, so she was put on mechanical ventilation. Her blood cultures were positive for methicillin-resistant Staphylococcus pseudintermedius, a multi-drug-resistant zoonotic bacteria. It was discovered that the source of the bacteria was the family’s two pet dogs.
The young girl required extensive medical intervention and spent 90 days in the hospital and 60 days in the pediatric intensive care unit before she was discharged to a rehabilitation facility, still requiring ventilation support. This case illustrates that as drug resistance grows as a global public health concern, a One Health approach, acknowledging the interconnectedness of the health of humans, animals, and the environment, is needed to control its emergence and spread.
People across the world and across cultures share their lives with animals, but as entwined as our lives are, we may be unaware of the risk posed by antimicrobial-resistant zoonotic microbes. Drug resistance or antimicrobial resistance (AMR) develops when microbes (such as bacteria, viruses, fungi, and parasites) change over time and become resistant to medicines, making infections difficult to treat and raising the risk of disease spread and severity. Antimicrobial-resistant microbes can transfer zoonotically between animals and humans and vice versa.
In the case of the 12-year-old girl previously mentioned, her two pet dogs routinely slept in bed with her. The zoonotic potential of some AMR bacteria means infection prevention measures should be taken by pet owners to minimize risk, particularly if any members of the household are immunocompromised.
As a Certified Veterinary Technician with over 25 years of experience caring for dogs and cats, I have come to appreciate the interconnectedness of people’s lives with their pets. It is because of the amazing power of the human-animal bond that I have spent my career in the service of animals and have come to understand the links between human health and animal health.
The positive benefits of animal companionship on human health arise from simply interacting and sharing our lives with them. This interaction has been shown to have many positive physical and mental health effects such as decreased blood pressure, heart rate, and cortisol levels (a stress-related hormone), as well as reduced loneliness, increased feelings of social support and unconditional love, and improved mood. Animal companionship has even been linked to neurologic benefits for individuals with attention deficit/hyperactivity disorder and on the autism spectrum. Companion animals receive food, shelter, and medical care, as well as their share of unconditional love and affection from their human caregivers. However, there are also potential health risks for both pets and the people who love them due to their communal lives, and one emerging risk is mutual exposure to antimicrobial-resistant germs.
In addition to the risk of zoonotic transfer of AMR infections from pets to their human caregivers and vice versa, resistant infections are becoming more prevalent in pet dogs and cats. Cases of multi-drug-resistant infections are increasing in companion animals, most commonly in the urinary tract, skin, ears, respiratory tract, wounds, and surgical sites. To treat AMR infections in veterinary patients, antibiotics developed for human use have been used. While some of these drugs have been effective, many bacteria causing infections in pets already show resistance to these drugs. Additionally, as increasing AMR is a growing concern in human medicine, there is an argument for the discontinuation of the use of these drugs in veterinary patients to preserve their effectiveness for humans.
In my career I have seen serious AMR infections that have required drastic interventions, including amputation, to stop the spread. I’ve also lost many companion animal patients to drug-resistant infections. Bella* was a 14-year-old Beagle with transitional cell carcinoma (TCC), a malignant cancer of the urinary tract. Because of the location of the cancer, urinary tract infections (UTIs) are a common complication in patients with TCC. One day, Bella came to the hospital very sick, and her family was certain her cancer had progressed and spread throughout her body. Her medical team was thrilled to discover that her tumor was actually shrinking in response to chemotherapy and she only had a UTI – an infection that should easily have been treated with antibiotics. However, as weeks passed and the antibiotics were not working, Bella’s bladder infection ascended into her kidneys making her sicker. Tests revealed that her infection was caused by a multi-drug resistant strain of E. coli. Sadly, the bacteria causing Bella’s infection could only be treated with a small selection of antibiotics that were prohibitively expensive, potentially damaging to her kidneys, or ethically must be reserved for use in human medicine. After three weeks of battling infection, Bella’s family made the difficult decision to let her go and she was euthanized.
A One Health approach requires the participation of the veterinary community in the battle against AMR. We must demonstrate responsible antimicrobial stewardship to address our role in the AMR crisis. This starts with the education of pet caregivers. Many people do not know the complexities of their pet’s illness or understand the proper use of antibiotics. This lack of understanding can lead to the misuse of antibiotics and the spread of AMR. Maintaining their pet’s overall health is crucial for disease prevention and thus the reduction in the use of antimicrobials. General health can be maintained through good diet and care practices, as well as regular vaccination and antiparasitic measures. Within the walls of the veterinary hospital, stringent infection control, prevention, and biosecurity measures must be followed to reduce hospital-acquired infections and the transfer of AMR between patients as well as from animals to humans and humans to animals.
Antimicrobial stewardship also requires veterinarians to practice the judicious use of antimicrobials including prescribing antibiotics only when necessary, treating infections based on bacterial culture and sensitivity, and treating with a sufficient dose and for a sufficient duration to ensure all infectious bacteria are eliminated. Just as in human medicine, we must push to develop rapid diagnostic tests to ensure we use the right antimicrobials at the right times. Veterinary care units also need standardized methods of sample collection, handling, and testing. And finally, we must develop national and international surveillance systems so that data can be collected, tracked, shared, and compared to monitor trends in AMR in veterinary medicine. Together, we can tackle AMR, improve human and animal health, and preserve the human-animal bond.
*Bella’s name has been changed to maintain confidentiality.
Edited by Samantha Serrano
Guest Blogger
Daryl Makosky is a mother, student, and veterinary professional with a passion for One Health. Daryl earned her Bachelor’s Degree in Creative Writing from the University of Colorado, Boulder, then went on to earn her Associate’s Degree in Veterinary Technology from Bel-Rea Institute of Animal Technology. She is a Certified Veterinary Technician with nearly 25 years of experience in specialty small animal medicine as well as a graduate student earning her Master’s in Public Health from the George Washington University. Daryl’s goal is to work in One Health to improve the health of people, animals, and the environment. Daryl lives outside Denver, Colorado, U.S.A. with her partner, their children, and pets, and enjoys reading and spending time in the beautiful Rocky Mountains.
