Something new to scare you: A recent study by researchers from the University of Houston found that 40 percent of doorsteps samples are contaminated with infectious C. difficile bacteria — and so were 39 percent of shoe soles, Yahoo.com reports.

C. diff, isn’t easy to treat and several strains are resistant to antibiotics. Recent research published in the New England Journal of Medicine suggests 500,000 people are infected with C. diff per year.

“Shoes are contaminated from diverse sources, and we are regularly contaminating our doorsteps by shoes,” said the study’s author M. Jahangir Alam. Primary sources include excrement from animals, including birds.

To avoid tracking germs into your house, the solution is simple: Take off your shoes at the door, Alam suggests.