Professor Thomas Riley1, Ms Su Chen Lim2, Dr Peter Moono2, Ms Sicilia Perumalsamy2, Dr Niki Foster3
1PathWest, Nedlands, WA, Australia
2UWA, Crawley, WA, Australia
3WA Department of Health, Shenton Park, WA, Australia
Introduction: Despite remaining a major hospital pathogen, Clostridium difficile infections (CDIs) have been increasing in the community. Non-human reservoirs of CDI include both production and companion animals, and food and the environment is being contaminated via animal manure. However, the extent of this environmental contamination is poorly understood. Here we provide further insight into potential sources of community-acquired CDI in WA.
Methods: Multiple samples of soil, mulch, compost, lawn, manure and vegetables were collected in Perth, WA. All samples were processed using published methods. PCR-based toxin gene profiling and ribotyping was performed, and ribotypes (RTs) identified by comparing banding patterns to our reference library.
Results: C. 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. Approximately 30% of mulch, compost and manure samples from gardening centres in Perth were contaminated. The overall prevalence of C. difficile in lawn was 59%. C. difficile was isolated from 86 out of 145 (59.3%) samples collected from gardens/lawns around public hospitals in Perth.
Conclusions: These studies identified C. difficile in multiple sources/reservoirs external to the hospital. C. difficile has always been found in soil contaminated by animal manure, however, the extent of contamination has increased recently. The risk of acquiring C. difficile from these sources/reservoirs remains unclear. Additional studies are required to determine how C. difficile may be introduced into hospitals from community sources.
BIOGRAPHY
After 15 years working in diagnostic laboratories and completing a PhD part-time at UWA in 1984, Tom was appointed Senior Medical Scientist in Charge of Clinical Microbiology at Sir Charles Gairdner Hospital in 1988. In 1993-4, he undertook a Masters degree in Applied Epidemiology at ANU and, in 1995, was appointed as an Associate Professor in Microbiology at UWA, and Principal Research Scientist at PathWest Laboratory Medicine (WA). In 2002, he was awarded a Personal Chair at UWA. He is currently a Professorial Research Fellow at Edith Cowan University and Professor of Public Health at Murdoch University, and has had a long standing interest in the pathogenesis, diagnosis and epidemiology of disease caused by Clostridium difficile.