Drug-resistant bacteria has become one of the major health issues of this century. The fact that some harmful microorganisms can adjust to all our medicine and become nearly impossible to treat is extremely scary. For example, there’s already a strain of gonorrhea that’s essentially untreatable, and drug-resistant pathogens cause the death of over one million people a year.
The extent of the problem is not fully understood, and it’s not limited to humans. Animals on farms can also carry drug-resistant bacteria. Moreover, there may be a new issue. In a recent study, researchers discovered that these “superbugs” are being transmitted from pets to their owners. Although this isn’t necessarily making the humans sick, this suggests that pets may also contribute to the health crisis.
Our best friends and microbes
If you have a dog or a cat, you probably have a lot of physical contact. Let’s be honest — the petting, the kissing, the sharing a room (and often, a bed) — we all love to snuggle our little munchkins. We don’t usually think about germs when we do this, but germs can be transmitted in this process — in both directions.
In the new research, an international team investigated 43 households in Portugal (5 cats, 38 dogs, 78 humans) and 22 households in England (22 dogs and 56 humans), finding that pets can serve as a reservoir for superbugs.
All of the humans were healthy. Even if their pets transmitted drug-resistant bacteria, this didn’t seem to make them sick. Remarkably, however, all of the pets had at least one infection (whether skin, soft tissue, or urinary tract).
The researchers collected urine and fecal samples from the pets, as well as skin swabs. They focused on Enterobacterales (a broad family of bacteria that includes E. coli) that were resistant to third-generation cephalosporins. These are some of the most critical antibiotics for humans, treating a broad range of conditions, from sepsis to meningitis. The team also looked at bacteria resistant to carbapenems — often considered the last line of antibiotic defense used when other antibiotics fail.
In Portugal, 3 cats and 21 dogs harbored bacteria resistant to cephalosporins, and one dog also had bacteria resistant to carbapenems. Furthermore, in five households, both the pets and the owners had the same bacteria, a sign that the pathogens passed from one to the other. The dog that had bacteria resistant to carbapenems was also among this group.
Meanwhile, in the UK, one dog carried bacteria resistant to both classes of antibiotics, and two households showed signs of bacteria passing between pets and humans.
Addressing AMR bacteria transmission
“Recent research indicates that the transmission of antimicrobial resistance (AMR) bacteria between humans and animals, including pets, is crucial in maintaining resistance levels, challenging the traditional belief that humans are the main carriers of AMR bacteria in the community,” says lead researcher Juliana Menezes, of the Antibiotic Resistance Lab at the Centre of Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon.
“Understanding and addressing the transmission of AMR bacteria from pets to humans is essential for effectively combating antimicrobial resistance in both human and animal populations.”
It’s not 100% clear whether the pets passed the bacteria to humans or the other way around. But, given that the pets were sick and the humans were not, the former seems more likely. The researchers suggest that if your pet has such bacteria, you should clean your house very thoroughly and consider taking measures to reduce the risk of transmission.
But maybe the most important discovery is that our animals can carry these bacteria. This is especially true if they go outside. Even if they are not causing illness in us, this could be adding to overall antibiotic resistance.
“Our findings emphasize the importance of including households with pets in national programs that track levels of antibiotic resistance,” Menezes said in a press release about the meeting. “Learning more about resistance in pets would help in creating well-informed and targeted actions to protect both animal and human health.”
All the pets were successfully treated for their infections. The owners did not need any treatment.
The research will be presented at the ESCMID Global Congress in Barcelona, Spain, from April 27 to April 30
