• Posted March 20, 2023

In Rare Cases, Drug-Resistant 'Superbugs' Can Pass Between People & Their Pets

In more bad news about antibiotic resistance, new research suggests that people and their pets may be able to transmit multidrug-resistant germs to each other.

Still, cases of cross-transmission are rare and it's not clear if pets are giving germs to people or people are giving germs to their pets, the study authors noted.

"In urban areas in high-income countries, pets do not seem to be a multidrug-resistant reservoir of high importance," said lead researcher Dr. Carolin Hackmann, from Charité University Hospital Berlin, in Germany. "Still, good hygiene practices in contact with pets should be kept up to further prevent transmission of multidrug-resistant organisms."

The study can't prove that people and pets made each other sick, only that both shared a common disease and Hackmann said she wouldn't recommend that "vulnerable persons get rid of their pets, since transmission was very rare."

Using nasal and rectal swabs, Hackmann and her colleagues looked for the antibacterial-resistant diseases methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), 3rd generation cephalosporin-resistant Enterobacterales (3GCRE) and carbapenem-resistant Enterobacterales (CRE), in nearly 2,900 hospitalized patients between June 2019 and September 2022.

More than 600 pet owners then were asked to send throat and stool swab samples of their pets; of these, 300 sent samples from 400 pets.

Of these samples, 15% of dogs and 5% of cats had at least one multidrug-resistant germ. In four cases, these bacteria matched the owner's bacteria. But only one of the pairs was genetically identical in a dog and its owner, the researchers found.

The findings are scheduled to be presented April 15 at the annual meeting of the European Congress of Clinical Microbiology & Infectious Diseases, in Copenhagen. Findings presented at medical meetings should be considered preliminary until published in a peer-reviewed journal.

"For years, people have implicated dogs and cats as carriers of MRSA and group A strep, but they're rarely thought to be a significant fomite [likely to carry infection] in transmissions between people and animals. It can happen, but it happens rarely," said Dr. Bruce Farber, chief of public health and epidemiology at Northwell Health in New Hyde Park, N.Y.

Farber believes there is a real danger of disease transmission between people and animals, but not from household pets.

"There is no question that zoonosis, which is infections from animals in humans, has become a very big problem as has been seen in COVID and avian flu," he said.

It is not the interaction between people and pets that worries Farber, but rather between people and animals on commercial farms and even in the wild.

"It's those types of interactions that scare me a lot. Because that's where a jump could occur," he said. "Those types of transmissions are frightening and scary in terms of multidrug-resistant organisms."

More information

For more on diseases transmitted by animals to people, head to the U.S. Centers for Disease Control and Prevention.

SOURCES: Carolin Hackmann, MD, Charité University Hospital, Berlin, Germany; Bruce Farber, MD, chief, public health and epidemiology, Northwell Health, New Hyde Park, N.Y.; April 15, 2023, presentation European Congress of Clinical Microbiology & Infectious Diseases, Copenhagen, April 15, 2023