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

A recent outbreak of leptospirosis in dogs in Phoenix, Arizona got me thinking about the role veterinarians play in public health. Over fifty 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, and this fact can easily be lost in the shuffle of trying to keep your pup 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, multi-drug resistant organisms (MDRO’s) 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 fewer range of antibiotics to use to treat infections, but it occurred to me that the discussion of MDRO’s 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” refer 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 (AMR) 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 treatment of anti-inflammatories, antibacterials, aerosolized antimicrobial therapy, etc. These were all the tactics we had used when attempting to treat our dog for his persistent pneumonia over the course of nine months. I began to read more about the risks for MDRO transmission in animals and I wondered, are we so focused on AMR 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 MDRO’s?

In epidemiology and infectious disease work, we see wild animals such as bats and non-human 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 in regards to the animals in our home 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 AMR 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%.”

MDRO’s such as 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 veterinary 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 vet if there was a way to get ahold 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 who 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.