Clostridium Difficilein Soil Conditioners, Mulches And Garden Mixes With Evidence Of A Clonal Relationship With Historical Food And Clinical Isolates

With rates of community-associatedClostridium difficileinfection (CA-CDI) increasing worldwide, potential reservoirs/sources ofC. difficilein the community are being sought. SinceC. difficileis found in animal manure and human biosolids, which are composted for agricultural purposes, composted products could be a source. In this study, the presence ofC. difficilein composted products, and their genetic relatedness to other previously isolated strains from humans, root vegetables and the environment in Western Australia, was investigated. Overall,C. difficilewas found in 22.5% (16/71) of composted products [29.7% (11/37) of soil conditioners, 16.7% (2/12) of mulches and 13.6% (3/22) of garden mixes]. FifteenC. difficilePCR ribotypes (RTs) were identified, the most common toxigenic strains being RTs 020 and 056.Clostridium difficileRT 056 is commonly associated with CDI in humans and has also been isolated from cattle, root vegetables and the environment (veterinary clinics and lawn) in Australia. High-resolution core-genome analysis of 29C. difficileRT 056 strains revealed clonal relationships between isolates derived from humans, vegetables, composted products and the environment. These findings provide support for an intricate transmission network between human, food and the environment, further highlighting the importance of a 'One Health' approach for managing CDI.