Potential Transfer of Clostridium difficile From Dog, Cat to Household Owners

Denise Rabold, doctoral student, research associate,Institute of Microbiology and Epizootics

Denise Rabold, doctoral student

Despite the low risk for Clostridium difficile (C. difficile) passing between a cat or dog and their owner, the risk can’t be counted out, according to new research.

Researchers from Germany collected fecal samples from pets, such as cats and dogs in order to analyze the potential zoonotic transmission of C. difficile from animals to human owners. A total of 1418 fecal samples were collected between July 2012 and August 2013 all across Germany; 415 households were included in the study.

The pet owner, living in the same house with their pet, filled out a questionnaire and provided a fecal sample from each household member. The survey included basic data and about C. difficile factors such as antibiotic use, but also asked about residential environment (such as the countryside). The researchers also collected data about the pets, such as breed, age, sex, whether the animal was neutered, kept inside or outside the house, and if they participated in shows or other activities on differed sites.

The study authors explained that C. difficile infection reports in dogs demonstrate that companion animals can be a source of community-acquired infection in humans, though the data is scarce, especially in Germany, where research into such topics is restricted to cats and dogs in animal shelters only, and better studies haven’t been published in the last 30 years.

The analysis showed that the prevalence associated with C. difficile infection in households with pets was about 3%; the researchers said this is about the same as the rest of the community. The researchers also wrote that it was important to note C. difficile did not occur simultaneously in animals and humans sharing the same household.

“The same good hygienic practice for potentially pathogenic bacteria also applies for C. difficile,” study author Denise Rabold, doctoral student, research associate, Institute of Microbiology and Epizootics, Germany, told MD Magazine. “Sharing the same environment makes certain demands on pet-keeping households but does not demand specific requirements to prevent infections with C. difficile. That means, for example, that we would not essentially recommend sleeping in the same bed but encourage hand hygiene for pet owners. However, if a C. difficile infection index case lives in the same household, advanced hygienic measurements should be applied to disable the spread of vegetative cells and spores of C. difficile — this implies also for disinfectants with an effective spectrum of activity against spores.”

Rabold said C. difficile has low isolation rates among cats, dogs and their owners, and the evidence of a high overlap in relevant ribotypes, as well as the risk assessment of the data from the survey, could suggest that there is zoonotic potential.

Despite all that, Rabold added that her findings are an “important tile in the puzzle of C. difficile infection epidemiology,” noting that other findings could dispel the team’s research.

The risk factors described for C. difficile humans still apply to animals — such as age, hospitalization, prior antibiotic use and contact with fecal matter or diarrhea — the researchers concluded. Thus, in order to discover possible sources for community-acquired C. difficile and understand the zoonotic potential, more studies are needed.

The paper, titled “The zoonotic potential of Clostridium difficile from small companion animals and their owners,” was published in the journal Plos One.