Detection and characterisation of Clostridium difficile in Australian Thoroughbred foals

Diarrhoea is a common disease in young foals that is labour intensive and costly to manage. A large number of infectious agents have been detected in foals with diarrhoea, but the pathogenic importance of many of these agents is poorly understood. Clostridium difficile has been associated with severe necrotising enteritis in foals, but has also been isolated from healthy foals. Hypervirulent strains of C. difficile, such as ribotypes 027 and 078, commonly associated with human hospital outbreaks of diarrhoea, have also been detected in some animal populations. There are limited data on C. difficile disease in Australian horses. In a prospective case control investigation of diarrhoea in foals, faecal samples were collected on five Thoroughbred breeding farms in New South Wales, Australia, from foals with diarrhoea and age-matched control foals (agematched pair). In addition, faeces were collected from foals with diarrhoea at an equine referral hospital. Foal faeces were tested for the presence of C. difficile using a quantitative polymerase chain reaction assay (qPCR) targeting the gene encoding triose phosphate isomerase. Anaerobic culture for C. difficile was performed on samples that tested positive by qPCR and isolates were further characterised by ribotyping. In total, 117 age