Vermin on pig farms are vectors for Clostridium difficile PCR ribotypes 078 and 045

Clostridium difficile is a gram positive, spore forming, toxin producing, anaerobic bacteria and an opportunistic pathogen for Man and many animal species, causing diarrhea in young piglets. Piglets probably become colonized from the environment. To investigate the possible spread and transmission of C. difficile by vermin, vermin samples were collected on a pig farm in the Netherlands and investigated for the presence of C. difficile. Samples of house mice (n=53), drain flies (n=39), lesser houseflies (n=95), and yellow mealworms (n=11) were found positive for C. difficile in 66%, 97%, 56% and 100% of cases respectively. C. difficile PCR ribotype 078 was found in all categories of vermin and ribotype 045 was found in two samples from the skeletal muscle of mice. House sparrows found dead on the premises (n=35) and bird droppings (n=26) were also investigated and carried C. difficile in 66% and 4% of cases respectively. PCR ribotype 078 was identified in bird and droppings samples but ribotype 045 was not. We conclude that vermin can play a role in the spread and transmission of C. difficile types 078 and 045 within pig farms and to other locations.