TUESDAY, Sept. 15, 2026 (HealthDay News) —  Here’s an unwelcome bit of news as Fido or Socks cuddles up to you for attention — they could be carrying antibiotic-resistant strains of a bacterium known to cause serious infections.

Nearly half of samples collected from dogs and cats across dozens of countries contained strains of Klebsiella pneumoniae with high levels of antibiotic resistance, researchers reported recently in the journal Transboundary and Emerging Diseases.

Klebsiella — a bacteria found in human feces — can cause pneumonia, sepsis and urinary tract infections, researchers said in background notes.

“This study does not tell us that our pets are making us ill, but [what] it does show is that very closely related bacterial strains can be found across animals and humans,” lead researcher Stephen Fordham said in a news release. He is a lecturer in biosciences at Bournemouth University in the U.K.

“There is no need for owners to be concerned but this does show the importance of including our pets in wider efforts to understand and tackle antimicrobial resistance,” Fordham said.

For the study, researchers analyzed 712 samples of Klebsiella collected from pet dogs and cats in 25 countries and compared them with more than 38,000 human samples of the bacteria.

About 87% of Klebsiella from pets belonged to strains that also have been identified in people, although researchers stressed that this does not on its own prove that the bacteria pass between pets and owners.

Genetic analysis also revealed that about 43% of the Klebsiella bacteria collected from pets in 23 countries had developed resistance to at least one type of antibiotic.

Of those antibiotic-resistant samples, about 80% from cats and 56% from dogs were resistant to multiple drugs, the study found.

One strain in particular, known as ST147, raised concern. This multi-drug-resistant strain was closely related — and in some cases, nearly genetically identical — across samples taken from dogs, cats and people.

“It shows that companion animals can carry closely related, clinically consequential multi-drug-resistant lineages overlapping” with those found in humans, researchers concluded in their paper.

More information

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

SOURCES: Bournemouth University, news release, Sept. 10, 2026; Transboundary and Emerging Diseases, Aug. 28, 2026