The Infectious Bond Between People and Their Pets

By Jane Farrell

Humans and their animal companions exchange the bacteria for the antibiotic-resistant MRSA, according to a new study.

The findings were published in mBio, the journal of the American Society for Microbiology.

MRSA naturally lives on the skin and causes difficult-to-treat infections in humans and animals. It is hard to treat because over time it has become resistant to antibiotics.

 “Our study demonstrates that humans and companion animals readily exchange and share MRSA bacteria from the same population,” said senior author Mark Holmes, senior lecturer in preventive veterinary medicine at the University of Cambridge in England.

The investigators used genetic sequencing to analyze 46 MRSA samples from cats and dogs in several British veterinary hospitals, and found that they were very similar to MRSA samples in humans. Most of the human strains come from wound infections or skin and soft tissue infections.

Researchers also found that samples from the same veterinary hospitals they studied were clustered together genetically, suggesting that as in human hospitals, MRSA can be readily transmitted in veterinary hospitals.

“It’s a reminder that constant vigilance and high levels of hygiene are just as important when treating cats and dogs as with humans,” Holmes says.

But Holmes says pet owners don’t need to worry.

“MRSA infection in cats and dogs is still extremely rare,” Holmes says. “There is very little risk of owners getting ill from their pets.”

He also said that healthy pets aren’t likely to get MRSA from their human companions. But if a pet already is ill or its health is severely compromised, MRSA patients should tell their pets’ veterinarians.