Aims The incidence of community-associated Clostridium difficile infection (CA-CDI) in Australia has increased since mid-2011. With reports of clinically important C. difficile strains being isolated from retail foods in Europe and North America, a foodborne source of C. difficile in cases of CA-CDI is a possibility. This study represents the first to investigate the prevalence and genotypes of C. difficile in Australian retail vegetables. Methods and Results A total of 300 root vegetables grown in Western Australia (WA) were collected from retail stores and farmers’ markets. Three vegetables of the same kind bought from the same store/market were treated as one sample. Selective enrichment culture, toxin profiling and PCR ribotyping were performed. Clostridium difficile was isolated from 30% (30/100) of pooled vegetable samples, 55·6% of organic potatoes, 50% of nonorganic potatoes, 22·2% of organic beetroots, 5·6% of organic onions and 5·3% of organic carrots. Over half (51·2%, 22/43) the isolates were toxigenic. Many of the ribotypes of C. difficile isolated were common among human and Australian animals. Conclusions Clostridium difficile could be found commonly on retail root vegetables of WA. This may be potential sources for CA-CDI. Significance and Impact of the Study This study enhances knowledge of possible sources of C. difficile in the Australian community, outside the hospital setting.

Clostridium difficileis a well-established hospital pathogen. Recently, it has been detected increasingly in patients without hospital contact. Given this rise in community associated infections withC. difficile, we hypothesized that the environment could play an important role in transmission of spores outside the hospital. Lawn samples (311) collected in public spaces in the metropolitan area of Perth, Western Australia, from February to June 2016 were cultured forC. difficile. C. difficilewas isolated from the samples by direct and enrichment culture, and characterized by standard molecular methods using toxin gene PCR and ribotyping. The overall prevalence ofC. difficilewas 59%, new lawn (≤4 months old) was twice as likely as old lawn (>4 months old) to test positive (OR = 2.3; 95%CI 1.16–4.57,p = 0.015) and 35 C. difficileribotypes were identified with toxigenic ribotype 014/020 (39%) predominating. The highest viable count from lawn soil samples was 1200 CFU/g. These results show that lawns in Perth, Western Australia, harbor toxigenicC. difficile, an important finding. The source of lawn contamination is likely related to modern practice of producing “roll-out” lawn. Further work should focus on identifying specific management practices that lead toC. difficilecontamination of lawn to inform prevention and control measures.

Summary: With rates of community‐associated Clostridium difficile infection (CA‐CDI) increasing worldwide, potential reservoirs/sources of C. difficile in the community are being sought. Since C. difficile is found in animal manure and human biosolids, which are composted for agricultural purposes, composted products could be a source. In this study, the presence of C. difficile in 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. difficile was 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]. Fifteen C. difficile PCR ribotypes (RTs) were identified, the most common toxigenic strains being RTs 020 and 056. Clostridium difficile RT 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 29 C. difficile RT 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.