Background: Clostridium difficile infections (CDI) in humans range from
asymptomatic carriage to life-threatening intestinal disease. Findings on C.
difficile in various animal species and an overlap in ribotypes (RTs) suggest
potential zoonotic transmission. However, the impact of animals for human CDI
remains unclear. Methods: In a large-scale survey we collected 1,447 fecal
samples to determine the occurrence of C. difficile in small companion animals
(dogs and cats) and their owners and to assess potential epidemiological links
within the community. The Germany-wide survey was conducted from July
2012-August 2013. PCR ribotyping, Multilocus VNTR Analysis (MLVA) and PCR
detection of toxin genes were used to characterize isolated C. difficile
strains. A database was defined and logistic regression used to identify
putative factors associated with fecal shedding of C. difficile. Results: In
total, 1,418 samples met the inclusion criteria. The isolation rates for small
companion animals and their owners within the community were similarly low
with 3.0% (25/840) and 2.9% (17/578), respectively. PCR ribotyping revealed
eight and twelve different RTs in animals and humans, respectively, whereas
three RTs were isolated in both, humans and animals. RT 014/0, a well-known
human hospital-associated lineage, was predominantly detected in animal
samples. Moreover, the potentially highly pathogenic RTs 027 and 078 were
isolated from dogs. Even though, C. difficile did not occur simultaneously in
animals and humans sharing the same household. The results of the
epidemiological analysis of factors associated with fecal shedding of C.
difficile support the hypothesis of a zoonotic potential. Conclusions:
Molecular characterization and epidemiological analysis revealed that the
zoonotic risk for C. difficile associated with dogs and cats within the
community is low but cannot be excluded