Who's at risk? Sharing love, sharing germs

Dogs may be at risk from owners spreading E. coli, study says
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Mar 01, 2009

Manhattan, Kan. — We have all seen the sloppy, wet kiss from dog to owner. But who is really at risk?

People carry more drug-resistant strains of E. coli bacteria than their dogs, according to a study conducted by Dr. Kate Stenske, clinical research professor at the Kansas State University's College of Veterinary Medicine, as part of her doctoral research at the University of Tennessee.

The study, to be published in the American Journal of Veterinary Research, looked at how likely disease could be spread between owners and their dogs.

"I became interested in the topic because there is such a strong bond between dogs and their owners, Stenske says, adding that more than half of dog owners reportedly share food with their pets and more than half allow them to lick their faces and sleep in their beds. "If you look at one study, 84 percent of people say their dog is like a child to them."

The study focused on E. coli bacteria only, but Stenske says it didn't include studies on transmission or directionality of the bacterium.

But in 10 percent of dog-human pairs, Stenske found that owners and their dogs shared the same E. coli strains, which had more resistance to antibiotics than expected. The owners had more multiple drug-resistant strains than their dogs.

"This makes us think that dogs are not likely to spread multiple-drug resistant E. coli to their owners, but perhaps owners may spread them to their dogs," Stenske says.

Bonding behaviors appeared to have no association to shared bacteria in study subjects, but there was an association between antibiotic-resistant E. coli and owners who didn't wash their hands after petting dogs or before cooking meals, she adds.

"What we learn from this is that antibiotics really do affect the bacteria within our gastrointestinal tract, and we should only take them when we really need to," Stenske says.

Next, she says she may conduct a similar study on the relationship between shared E. coli and the behavior of cat owners.