Tom Riley1,2
1School of Biomedical Sciences, The University of Western Australia, 2Department of Microbiology, PathWest Laboratory Medicine (WA)
Biography:
BAppSc Curtin, MAppEpid ANU, PhD UWA
FASM, FRCPath, FAAM, FSHEA, FFSc(RCPA), FISAC
Tom divides his time in Perth, Western Australia, between PathWest Laboratory Medicine, WA’s public sector pathology service provider where he is a Senior Clinical Scientist, and The University of Western Australia where he is a Professor in the School of Biomedical Sciences. He has had a long-standing interest in diagnostic microbiology and healthcare-related infections, particularly the diagnosis, pathogenesis and epidemiology of Clostridioides (Clostridium) difficile infection (CDI). This had led to a One Health approach to CDI. He is a Fellow of many professional societies and has published >450 book chapters and refereed journal articles, including >250 on C. difficile.
Abstract:
Clostridium difficile remains a major hospital pathogen, however, C. difficile infections (CDIs) have been increasing in communities worldwide. The Australian Commission on Safety & Quality in Health Care estimates that >80% of CDI in Australia is now community-associated. Non-human reservoirs of C. difficile include animals, with production animals likely most important. While food and the environment are being contaminated by animal manure, the extent of this contamination is poorly understood. Here we provide insight into potential sources of community-associated CDI in Australia. Multiple samples of soil, mulch, compost, lawn, manure, vegetables and household surfaces were collected in Perth and Brisbane. Moistened sterile cellulose sponges (Medical Wire & Equipment, England) were used to swab countertops/chopping boards and hard surfaces (ethical approval from the UWA Human Research Ethics Committee). All samples were processed using published methods. PCR-based toxin gene profiling and ribotyping was performed, and ribotypes identified by comparing banding patterns to our reference library. C. difficile was isolated from virtually everywhere e.g. 35% of 255 potatoes and 20% of 305 onions from 43 retailers, 4% of countertops/chopping boards, and ~30% of mulch, compost and manure samples from gardening centres. The overall prevalence of C. difficile in lawn was 59%. C. difficile was identified in multiple sources/reservoirs. These findings allowed production of a Causal Loop Diagram (CLD) showing key feedback loops associated with transmission of C. difficile in Australia. The risk of acquiring C. difficile from these sources/reservoirs remains unclear but the CLD shows possible points for interventions to reduce this risk.