The anaerobic spore-forming bacterium Clostridium difficile is a major human pathogen, the most commonly diagnosed cause of infectious hospital diarrhoea. Toxigenic isolates of C. difficile usually produce two toxins, A and B, and these are thought of as the major virulence factors. C. difficile is also a known cause of diarrhoea, necrotizing enteritis and death in horses. As with humans, predisposing factors for infection include hospitalisation, antimicrobial use and interaction with infant animals. C. difficile in horses could potentially act as a reservoir for zoonotic spread, as well as pose a danger to horses exposed to antimicrobials. Horses occupy an interesting position in relation to C. difficile in Australia, with overlapping domains of performance, companion and wild animal. The potential for dissemination of C. difficile could encompass transfer through interaction, consumption and indirectly through exposure to horse manure. The ubiquitous nature of C. difficile makes a One Health approach vital. In humans, community-acquired C. difficile infection is increasing, and reasons for this are not well understood. Horses represent a unique animal population about which little is known in Australia. The over-arching aim of this project is to investigate the presence and characteristics of C. difficile in Australian horse populations.