Antimicrobial Resistance in Pets: Are We Ignoring a Looming Threat?

March 14, 2017
Saskia V. Popescu

An infection preventionist whose dog succumbed to drug-resistant pneumonia wonders whether animals are being overlooked in the fight against antimicrobial resistance.

A recent outbreak of leptospirosis in dogs in Phoenix, Arizona got me thinking about the role veterinarians play in public health. More than 50 dogs in the area have been afflicted with the bacteria, and public health officials are encouraging people to avoid dog parks.

Leptospirosis can also infect humans, though, a fact can easily be lost in the shuffle of trying to keep dogs safe. Late last year we lost one of our dogs to a drug-resistant pneumonia, which frankly is not something I thought would happen in a dog. As an infection preventionist, multidrug-resistant organisms (MDROs) are the norm and a daily struggle.

During our time in the veterinary intensive care unit, I found out that not only do veterinarians have a smaller range of antibiotics available to treat infections, but it occurred to me that the discussion of MDROs and animals tends to focus on livestock and not so much on domesticated animals. This is with good reason, of course, given a recent report from the European Centre for Disease Prevention and Control (ECDC) and the European Food Safety Authority (EFSA), which noted “extremely high” levels of multidrug resistance in Salmonella in humans, animals, and food across Europe. In their report, “animals” refers to “food-producing animals” such as pigs and cattle.

Aside from the work that is being done to cut down on antibiotic usage in livestock, the lingering question about domestic pets and antimicrobial resistance kept gnawing at me. In early January, this question became stronger when it was announced that SeaWorld’s infamous orca, Tilikum—made famous in the documentary Blackfish—had died after battling “a persistent and complicated bacterial lung infection.” SeaWorld utilizes some of the top veterinarians and had reported using such treatment as anti-inflammatories, antibacterials, aerosolized antimicrobial therapy, and other medications to treat Tilikum. These were all the tactics we had used when attempting to treat our dog for his persistent pneumonia over the course of 9 months.

I began to read more about the risks for MDRO transmission in animals, and I wondered: Are we so focused on antimicrobial resistance in humans and livestock that we’re overlooking the use of antimicrobial treatments in pets? Are we missing a glaring chain in the transmission of MDROs?

In epidemiology and infectious disease work, we see wild animals such as bats and nonhuman primates as sources of emerging infectious diseases due to spillover. And yet, I wonder, are we ignoring a slowly growing public health issue in our very own homes? Veterinarians are truly a first line of defense in terms of zoonotic diseases, but are we paying attention to them with regard to the animals in our homes and wildlife centers?

We run to veterinarians when our pets fall sick (such as in the case of the leptospirosis outbreak), but what about the not-so-slowly-growing threat of antimicrobial resistance? There is a growing trend of antimicrobial resistance in animals and, although many note that the risk for transmission to humans is limited, the truth is that while we might think antibiotic resistance doesn’t get much attention, drug resistance in pets is getting even less.

The Journal of the American Veterinary Medical Association noted that in terms of antibiotic usage, it “seems likely that the amount of inappropriate use in companion animal settings is close to the most recent estimates in human medicine—50%.” MDROs such as methicillin-resistant Staphylococcus aureus (MRSA) are transmitted from humans; however, the overuse of antibiotics in veterinary medicine is aiding the evolution of resistant germs. To combat this, researchers such as Jeff Bender, DVM, professor at the College of Veterinary Medicine at the University of Minnesota, are working to provide guidance on antimicrobial stewardship programs in companion animal practices and other veterinary care settings. Dr. Bender and others have pointed to the absence of companion animals in the National Antimicrobial Resistance Monitoring System (NARMS).

Ironically, at a recent veterinary appointment, I asked our primary veterinarian if there was a way to get a hold of antibiograms or data on drug resistance. He laughed and said that there was no system in place for such issues and people do not seem that interested. In fact, veterinarians are commonly told to contact the pharmaceutical company that manufactured the drug if there are “problems.” Overall, as an infectious disease epidemiologist, infection preventionist, and lover of dogs, I worry that our current efforts to combat antimicrobial resistance are overlooking this obvious source for transmission and sentinel events.

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Saskia V. Popescu, MPH, MA, CIC, is a hospital epidemiologist and infection preventionist with Phoenix Children's Hospital. During her work as an infection preventionist she performed surveillance for infectious diseases, preparedness, and Ebola-response practices. She is currently a PhD candidate in Biodefense at George Mason University, where her research focuses on the role of infection prevention in facilitating global health security efforts. She is certified in infection control.