By Carol A. Kemper, MD, FACP

Clinical Associate Professor of Medicine, Stanford University, Division of Infectious Diseases, Santa Clara Valley Medical Center

Dr. Kemper reports no financial relationships relevant to this field of study.

SOURCE: Janezic S, Mlakar S, Rupnik M. Dissemination of Clostridium difficile spores between environment and households: Dog paws and shoes. Zoonoses Public Health 2018, April 23: doi:10.1111/zph.12475. [Epub ahead of print].

This quote is the best line I’ve ever heard — by Lucy Tompkins, MD, Stanford (my infectious disease attending many years ago).

Janezic et al examined the risk of acquiring Clostridium difficile when walking the dog (literally). The researchers examined 20 households in Eastern Slovenia with a pet dog. Five were urban households and 15 were rural. Samples from the shoes, household slippers, and dog paws were collected within 30 minutes of walking the dog or the owner returning from a walk. Duplicate samples were permitted in households with two dogs. All samples were submitted for PCR ribotyping and toxinotyping, as well as culture.

Ninety samples were collected from 20 households, including 25 from dog paws, 44 from shoes (both the right and the left), and 21 from household slippers. Of these, remarkably, C. difficile was detected on 31 of 90 specimens from 14 households. C. difficile was isolated from 43% of shoes, 28% of slippers, and 24% of dog paws. Altogether, 465 C. difficile isolates were obtained and sequenced, revealing 13 different ribotypes. Half were PCR ribotype 014/020, which was found in 18 different samples collected in eight homes. Five of these 13 ribotypes were toxigenic.

This study fits nicely with earlier work in New York City, which found that sand boxes and dog play areas often are contaminated with C. difficile. Basically, C. difficile is all around us. But it does make me wonder about the risk of spreading C. difficile in the hospital on my shoes. We don’t allow dogs in isolation rooms for this reason, but could my feet be a vector while I perform my daily rounds?