Clostridium difficile in Dutch animals: their presence, characteristics and similarities with human isolates

The presence and characteristics of Clostridium difficile were investigated in 839 faecal samples from seven different animal species in the Netherlands. The number of positive samples ranged from 3.4% (cattle) to 25.0% (dogs). Twenty-two different PCR ribotypes were identified. Among 96 isolates, 53% harboured toxin genes. All C. difficile isolates from pigs, cattle and poultry were toxinogenic, whereas the majority of isolates from pet animals consisted of non-toxinogenic PCR ribotypes 010 and 039. Ribotype 012 was most prevalent in cattle and ribotype 078 in pigs. No predominant ribotypes were present in horse and poultry samples. Overall, PCR ribotypes 012, 014 and 078 were the most frequently recovered toxinogenic ribotypes from animal samples. Comparison with human isolates from the Dutch Reference Laboratory for C. difficile at Leiden University Medical Centre (LUMC) showed that these types were also recovered from human hospitalized patients in 2009/2010, encompassing 0.8%, 11.4% and 9.8% of all isolates, respectively. Application of multiple-locus variable-number tandem-repeat analysis indicated a genotypic relation of animal and human ribotype 078 strains, but a clear genotypic distinction for ribotypes 012 and 014. We conclude that toxinogenic C. difficile PCR ribotypes found in animals correspond to PCR ribotypes associated with human disease in hospitalized patients in the Netherlands. Contrary to PCR ribotype 078, significant genetic differences were observed between animal and human PCR ribotype 012 and 014 isolates.