Clostridium difficile on Dog Paws & Human Footwear

In the Literature

Janezic S, Mlakar S, Rupnik M. Dissemination of Clostridium difficile spores between environment and households: dog paws and shoes. Zoonoses Public Health. 2018;65(6):669-674.

The Research …

Clostridium difficile causes disease in humans and some animal species (eg, horses), but its role in disease in dogs is enigmatic. Regardless of its pathogenicity in dogs, there is interest in the potential for dogs to act as a C difficile reservoir or vector. Healthy dogs can shed the bacterium,^1,2 and the same strains can be found in dogs and humans,^1,3 raising concerns that dogs may be able to directly infect humans or contaminate human environments. As recognition of community-associated C difficile infection in humans (ie, disease acquired in the community vs at a healthcare facility) increases, there is more need to investigate potential novel sources of exposure, including pets. This is a daunting task, as C difficile is widely present in various animals, food, and environments.^3-7

Although most of the focus on dogs and zoonotic enteropathogen risk has involved the study of feces, dogs can also carry pathogens on their body. In addition, dogs can act as sentinels for human exposure, as dogs tend to spend time in the same places as humans.

This study examined the isolation of C difficile from dog paws and human footwear in Slovenian households. C difficile was isolated from 14 of 20 (70%) households, including 19 of 44 (43.1%) shoes, 6 of 21 (28.6%) slippers, and 6 of 25 (24%) dog paws. When dog paws were positive, human footwear was usually positive also. The C difficile strains found were typical of strains found in humans, particularly ribotype 014/020.

These results provide more evidence that C difficile is relatively ubiquitous and that humans likely encounter it on a routine basis. Anything in the environment can contaminate footwear or dog paws. Neither the household environment nor outdoor sites were tested, so it is unclear whether contaminated paws and footwear reflect bacteria picked up inside or outside; however, presence of bacteria on slippers suggests that at least some were acquired inside the house.

… The Takeaways

Key pearls to put into practice:

• C difficile is one of many pathogens that can be found in the environment and, correspondingly, on dog paws. Whether and how dogs are involved in the transmission of C difficile to humans remains unknown, so owners should be educated to take routine prevention measures (eg, handwashing) after animal contact.

• These results show that contact with dogs means potential contact with pathogens from the dog and its environs.