Bacteria found in homes with dogs may help prevent allergies

Households with dogs are home to more types of bacteria, including varieties rarely found in households without dogs, U.S. researchers say. Dr. Rob Dunn of North Carolina State University and colleagues at the University of Colorado said the team wanted to learn what variables influence the microbial ecosystems in homes, and the biggest variable it has found so far is dog ownership. "We can tell whether you own a dog based on the bacteria we find on your television screen or pillow case," Dunn said in a statement. "For example, there are bacteria normally found in soil that are 700 times more common in dog-owning households than in those without dogs." These microbial differences may be important. For example, it's known women who have a dog when pregnant are less likely to have children with allergies. While there's no known causal link between the presence of a dog and the absence of allergies, it has been hypothesized that the difference is related to the women's exposure to a wider variety of microbes, said Dunn, the study's co-author. However, to this point there had been little data on what the differences in microbial populations might be. While this study doesn't demonstrate a causal link, it sheds more light on the subject, showing that dogs have a major influence on which microbes are found in people's homes. The study, published in Plos One, found 7,726 phylotypes, or kinds, of bacteria in homes and each of the locations sampled harbored its own unique collection of bacteria. For example, the types of bacteria found in refrigerators, on kitchen counters and on cutting boards tended to be similar because they were primarily linked to food, while the bacteria on doorknobs, pillow cases and toilet seats were also fairly similar and came from humans.