My email and phone have been lighting up over the past few days about news reports describing a study presented at a recent scientific meeting in San Francisco. I wasn’t there and the results aren’t published, so I don’t have a lot to go on, but here are some highlights from the news article on

The study was an assessment of the dynamics of transfer between people and visitation dogs in hospitals of a particular antibiotic resistant “superbug” called methicillin-resistant Staphylococcus aureus (MRSA).

  • Researchers looked at 45 kids who interacted with 4 visitation dogs – a relatively small sample size but an interesting study nonetheless.
  • About 10% of kids who didn’t have MRSA at first were carrying it after visits with the dogs. Whether that means they really became MRSA carriers or just had the bug transiently on their hands isn’t clear to me.
  • More time with dogs was associated with a greater risk of finding MRSA on the kids.
  • Kids were supposed to use hand sanitizers when interacting with dogs, but that wasn’t strictly enforced (so it probably wasn’t commonly done).

Is this surprising?

  • Yes and no.
  • We showed quite a few years ago that dogs that participate in hospital visitation programs are at increased risk of carrying MRSA, and that petting a dog that has been visiting people in hospital can transfer MRSA to someone’s hands (even when the dog’s not an MRSA carrier, i.e. the dog is simply mechanically transferring the bug from person to person on its body). This is a nice extension of that work, looking more at the dynamics of MRSA transfer.

Here are my take home messages:

  • Pet therapy programs have clear benefits, but they’re not zero risk (like most things in life). The cost-benefit needs to be considered in each case, but there are some basic precautions we can use to minimize the “cost” (risk) component.
  • MRSA is a human-associated bacterium, in the dog-human context. MRSA in dogs is typically acquired from people. Dogs can be a vehicle for MRSA transfer since they get touched frequently by multiple people. The more human contacts, the greater the chance that someone will deposit something on the dog’s haircoat.
  • Ultimately, it doesn’t matter if the dog is an MRSA carrier or if the person is an MRSA carrier, as long as basic hygiene practices are used. Most importantly, if the person washes their hands or uses a hand sanitizer before and after animal contact, the risk of transmission in both directions can be minimized.

The Society for Healthcare Epidemiology of America (SHEA) guidelines for programs involving animals in healthcare settings were published in Infection Control and Hospital Epidemiology in 2015.