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• Posted April 15, 2024

Pets Are Passing Drug-Resistant 'Superbugs' to Their Owners

Dogs and cats can pass antibiotic-resistant bacteria to their owners, raising concerns that household pets could be contributing to the world’s antibiotics crisis, a new study says.

Cases of these “superbugs” being passed between sick dogs and cats and their healthy owners have been identified in the U.K. and Portugal, according to research presented at the European Society of Clinical Microbiology and Infectious Diseases Global Congress in Barcelona.

The cases challenge “the traditional belief that humans are the main carriers of antimicrobial-resistant bacteria in the community,” said lead researcher Juliana Menezes, a doctoral student with the University of Lisbon’s Antibiotic Resistance Lab.

The World Health Organization says antibiotic resistance is one of the greatest public health threats facing humanity, researchers said in background notes.

Drug-resistant infections kill more than 1.2 million people each year, and that number is expected to rise to 10 million by 2050 if no action is taken.

The study involved 43 households in Portugal containing 78 humans, 38 dogs and five cats, and 22 U.K. households containing 56 humans and 22 dogs.

All the humans were healthy, but all the dogs were suffering from infections. Researchers tested fecal and urine samples and skin swabs taken from both pets and owners to look for bacteria resistant to common antibiotics.

Researchers identified five households in which both owners and pets -- one with a cat and four with dogs -- were both carrying bacteria that had developed resistance to cephalosporins.

Genetic analysis showed that the strains were exactly the same, indicating that the bacteria had passed between pet and owner.

Cephalosporins are used to treat a broad range of infections, including meningitis, pneumonia and sepsis, researchers said. The WHO classes them as among the most critically important antibiotics for human medicine.

Researchers also detected dogs containing bacteria resistant to carbapenems, which are part of the last line of defense in human medicine when other antibiotics have failed.

Ultimately, all the pets were successfully treated for their infections, researchers said.

It wasn’t possible to prove the direction of transmission, researchers said. However, in three of the Portuguese homes, the timing of the positive tests strongly suggest that the bacteria were passed from pet to human.

Bacteria can pass between pets and humans by simple affection – petting, touching and kissing. They also can spread through the handling of feces.

Researchers recommend that owners wash their hands after petting their dog or cat and after handling their waste.

“Our findings underline the importance of including pet-owning households in national programs that monitor levels of antibiotic resistance,” Menezes said in a meeting news release. “Learning more about the resistance in pets would aid in the development of informed and targeted interventions to safeguard both animal and human health.”

Because these findings were presented at a medical meeting, they should be considered preliminary until published in a peer-reviewed journal.

More information

The U.S. Centers for Disease Control and Prevention has more about antimicrobial resistance.

SOURCE: European Society of Clinical Microbiology and Infectious Diseases, news release, April 12, 2024