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  • Professor Tom Riley and the Clostridium difficile research group

    Professor Tom Riley and the Clostridium difficile research group

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Clostridium difficile

Clostridium difficile causes a spectrum of disease ranging from self-limiting diarrhoea to life-threatening pseudomembranous colitis, bowel perforation and sepsis. It is known to be the most important cause of infectious diarrhoea in hospitalised patients in many high-income countries. However, the rate of community-associated C. difficile infection (CA-CDI) cases, with no prior history of hospitalisation or antibiotics usage, is on the rise. Currently, CA-CDI cases account for 26% – 45% of all global CDI cases.

C. difficile is well-established in both humans and animals. Recently, it has also been found in food and the environment. There is a rising concern that CDI may have a zoonotic, foodborne or environmental aetiology. Our research aims to improve our understanding of the epidemiology of C. difficile and to use that knowledge to improve infectious disease control and management.

We are a multi-institutional research group based in Queen Elizabeth II Medical Centre in Nedlands with post-doctoral researchers and PhD students from ECU, UWA, Murdoch and Curtin University. We use epidemiological studies to investigate the risk factors for CDI, phenotypic profiling including antimicrobial susceptibility testing, sporulation and motility assays to characterise C. difficile strains, and genotypic profiling including molecular typing and whole-genome sequencing to investigate the relatedness and evolution of C. difficile.

For more information, contact Professor Tom Riley.

Current projects

  • Epidemiology of CDI in Australia and Asia.
  • Environmental and animal reservoirs of C. difficile in Western Australia.
  • C. difficile in cystic fibrosis patients.
  • Comparative phylogenomics and antimicrobial resistance in livestock-associated strains of C. difficile.
  • Evolution and transmission of C. difficile.

Postgraduate student project opportunities

  • Aspects of Clostridium difficile

For more information about postgraduate student project opportunities, visit the HDR student project listing on the SMHS HDR Students webpage.

Key publications (2017-2021)

  • Collins, D., Wu, Y., Tateda, K., Kim, H., Vickers, R., Riley, T. (2021). Evaluation of the antimicrobial activity of ridinilazole and six comparators against Chinese, Japanese and South Korean strains of Clostridioides difficile. Journal of Antimicrobial Chemotherapy, 76(4), 967-972. https://doi.org/10.1093/jac/dkaa522.
  • Lim, SC., Knight, D., Moono, P., Foster, N., Riley, T. (2020). Clostridium difficile in soil conditioners, mulches and garden mixes with evidence of a clonal relationship with historical food and clinical isolates. Environmental Microbiology Reports, 12(6), 672-680. https://doi.org/10.1111/1758-2229.12889.
  • Lew, T., Putsathit, P., Sohn, KM., Wu, Y., Ouchi, K., Ishii, Y., Tateda, K., Riley, T., Collins, D. (2020). Antimicrobial susceptibilities of Clostridium difficile isolates from 12 Asia-pacific countries in 2014 and 2015. Antimicrobial Agents and Chemotherapy, 64(7), Article number e00296-20. https://doi.org/10.1128/AAC.00296-20.
  • Imwattana, K., Putsathit, P., Leepattarakit, T., Kiratisin, P., Riley, T. (2020). Mild or Malign: Clinical Characteristics and Outcomes of Clostridium difficile Infection in Thailand. Journal of Clinical Microbiology, 58(9), Article number e01217-20. https://doi.org/10.1128/JCM.01217-20.
  • Hong, S., Putsathit, P., George, N., Hemphill, C., Huntington, P., Korman, T., Kotsanas, D., Lahra, M., McDougall, R., Moore, C., Nimmo, G., Prendergast, L., Robson, J., Waring, L., Wehrhahn, M., Weldhagen, G., Wilson, R., Riley, T., Knight, D. (2020). Laboratory-based surveillance of Clostridium difficile infection in Australian healthcare and community settings, 2013–2018. Journal of Clinical Microbiology, 58(11), Article number e01552-20. https://doi.org/10.1128/JCM.01552-20.
  • Imwattana, K., Knight, D., Kullin, B., Collins, D., Putsathit, P., Kiratisin, P., Riley, T., (2020), Antimicrobial resistance in Clostridium difficile ribotype 017. Expert Review of Anti-infective Therapy, epub ahead of Print (December), 10p., DOI: 10.1080/14787210.2020.1701436.
  • Collins, D., Sohn, KM., Wu, Y., Ouchi, K., Ishii, Y., Elliott, B., Riley, T., Tateda, K., (2020), Clostridioides difficile infection in the Asia-Pacific region. Emerging Microbes and Infections, 9(1), 42-52, DOI: 10.1080/22221751.2019.1702480.
  • Hall, L., White, N., Allen, M., Farrington, A., Mitchell, B., Page, K., Halton, K., Riley, T., Gericke, C., Graves, N., Gardner, A., (2020), Effectiveness of a structured, framework-based approach to implementation: the Researching Effective Approaches to Cleaning in Hospitals (REACH) Trial. Antimicrobial Resistance and Infection Control, 9(2020), Article 35, DOI: 10.1186/s13756-020-0694-0.
  • Perumalsamy, S., Putsathit, P., Riley, T., (2019), High prevalence of Clostridium difficile in soil, mulch and lawn samples from the grounds of Western Australian hospitals. Anaerobe, 60(December 2019), Article number 102065, DOI: https://doi.org/10.1016/j.anaerobe.2019.06.018.
  • Hong, S., Knight, D., Chang, B., Carman, R., Riley, T., (2019), Phenotypic characterisation of Clostridium difficile PCR ribotype 251, an emerging multi-locus sequence type clade 2 strain in Australia. Anaerobe, 60(December 2019), Article number 102066, DOI: 10.1016/j.anaerobe.2019.06.019.
  • Androga, G., Knight, D., Hutton, M., Mileto, S., James, M., Evans, C., Lyras, D., Chang, B., Foster, N., Riley, T., (2019), In silico, in vitro and in vivo analysis of putative virulence factors identified in large clostridial toxin-negative, binary toxin-producing C. difficile strains. Anaerobe, 60(December 2019), Article number 102083, DOI: 10.1016/j.anaerobe.2019.102083.
  • Luo, Y., Cheong, E., Bian, Q., Collins, D., Ye, J., Shin, JH., Yam, WC., Takata, T., Song, X., Wang, X., Kamboj, M., Gottlieb, T., Jiang, J., Riley, T., Tang, Y., Jin, D., (2019), Different molecular characteristics and antimicrobial resistance profiles of Clostridium difficile in the Asia-Pacific region. Emerging Microbes and Infections, 8(1), 1553-1562, DOI: 10.1080/22221751.2019.1682472.
  • Lim, SC., Knight, D., Riley, T., (2019), Clostridium difficile and One Health. Clinical Microbiology and Infection, In Press(2019), 7p., DOI: 10.1016/j.cmi.2019.10.023.
  • White, N., Barnett, A., Hall, L., Mitchell, B., Farrington, A., Halton, K., Paterson, D., Riley, T., Gardner, A., Page, K., Gericke, C., Graves, N., (2019), Cost-effectiveness of an Environmental Cleaning Bundle for Reducing Healthcare-associated Infections. Clinical Infectious Diseases, epub ahead of Print(July 30), 8p., DOI: 10.1093/cid/ciz717.
  • Collins, D., Riley, T., (2019), Clostridium difficile in Asia: Opportunities for One Health Management. Tropical Medicine and Infectious Diseases, 4(1), Article number tropicalmed4010007, DOI: 10.3390/tropicalmed4010007.
  • Mitchell, B., Hall, L., White, N., Barnett, A., Halton, K., Paterson, D., Riley, T., Gardner, A., Page, K., Farrington, A., Gericke, C., Graves, N., (2019), An environmental cleaning bundle and health-care-associated infections in hospitals (REACH): a multicentre, randomised trial. Lancet Infectious Diseases, 19(4), 410-418, DOI: 10.1016/S1473-3099(18)30714-X.
  • Imwattana, K., Knight, D., Kullin, B., Collins, D., Putsathit, P., Kiratisin, P., Riley, T., (2019), Clostridium difficile ribotype 017 - characterization, evolution and epidemiology of the dominant strain in Asia. Emerging Microbes and Infections, 8(1), 796-807, DOI: 10.1080/22221751.2019.1621670.
  • Roshan, N., Riley, T., Knight, D., Steer, J., Hammer, K., (2019), Natural products show diverse mechanisms of action against Clostridium difficile. Journal of Applied Microbiology, 126(2), 468-479, DOI: 10.1111/jam.14152.
  • Wehrhahahn, M., Keighley, C., Kurtovic, J., Knight, D., Hong, S., Hutton, M., Lyras, D., Wang, Q., Leong, R., Borody, T., Edye, M., Riley, T., (2019), A series of three cases of severe Clostridium difficile infection in Australia associated with a binary toxin producing clade 2 ribotype 251 strain. Anaerobe, 55(February 2019), 117-123, DOI: 10.1016/j.anaerobe.2018.11.009.
  • Alfayyadh, M., Collins, D., Tempone, S., McCann, R., Armstrong, P., Riley, T., Cook, A., (2019), Recurrence of Clostridium difficile infection in the Western Australian population. Epidemiology and Infection, 147(2019), article no. e153, DOI: 10.1017/s0950268819000499.
  • Imwattana, K., Wangroongsarb, P., Riley, T., (2019), High prevalence and diversity of tcdA-negative and tcdB-positive, and non-toxigenic, Clostridium difficile in Thailand. Anaerobe, 57(June 2019), 4-10, DOI: 10.1016/j.anaerobe.2019.03.008.
  • Knight, D., Riley, T., (2019), Genomic delineation of zoonotic origins of Clostridium difficile. Frontiers in Public Health, 7(June 2019), Article no.164, DOI: 10.3389/fpubh.2019.00164.
  • Putsathit, P., Neela, V., Joseph, N., Ooi, P., Ngamwongsatit, B., Knight, D., Riley, T., (2019), Molecular epidemiology of Clostridium difficile isolated from piglets. Veterinary Microbiology, 237(October 2019), Article 108408, DOI: 10.1016/j.vetmic.2019.108408.
  • Knight, D., Kullin, B., Androga, G., Barbut, F., Eckert, C., Johnson, S., Spigaglia, P., Tateda, K., Tsai, P., Riley, T., (2019), Evolutionary and Genomic Insights into Clostridioides difficile Sequence Type 11: a Diverse Zoonotic and Antimicrobial- Resistant Lineage of Global One Health Importance. mBio, 10(2), 17p., DOI: 10.1128/mBio.00446-19.
  • Collins, D., Carson, K., Riley, T., (2019), Microbiological evaluation of the ability of the DEKO-190 Washer/Disinfector to remove Clostridium difficile spores from bedpan surfaces. Infection, Disease and Health, 24(4), 208-211, DOI: 10.1016/j.idh.2019.07.001.
  • Kumar, N., Browne, H., Viciani, E., Forster, S., Clare, S., Harcourt, K., Stares, M., Dougan, G., Fairley, D., Roberts, P., Piromohamed, M., Clokie, M., Jensen, M., Hargreaves, K., Ip, M., Wieler, L., Seyboldt, C., Norén, T., Riley, T., Kuijper, E., Wren, B., Lawley, T., (2019), Adaptation of host transmission cycle during Clostridium difficile speciation. Nature Genetics, 51(9), 1315-1320, DOI: 10.1038/s41588-019-0478-8.
  • Brain, D., Barnett, A., Yakob, L., Clements, A., Riley, T., Halton, K., Grave, N., (2018), Reducing length of stay to improve Clostridium difficile-related health outcomes. Infection, Disease and Health, 23(2), 87-92, DOI: 10.1016/j.idh.2018.01.001.
  • Knetsch, C., Kumar, N., Forster, S., Connor, T., Browne, H., Harmanus, C., Sanders, I., Harris, S., Turner, L., Morris, T., Perry, M., Miyajima, F., Roberts, P., Pirmohamed, M., Songer, J., Weese, J., Indra, A., Corver, J., Rupnik, M., Wren, B., Riley, T., Kuijper, E., Lawley, T., (2018), Zoonotic Transfer of Clostridium difficile Harboring Antimicrobial Resistance between Farm Animals and Humans. Journal of Clinical Microbiology, 56(3), e01384-17, DOI: 10.1128/JCM.01384-17.
  • Brain, D., Yakob, L., Barnett, A., Riley, T., Clements, A., Halton, K., Graves, N., (2018), Economic evaluation of interventions designed to reduce Clostridium difficile infection. PLoS One, 13(1), e0190093, DOI: 10.1371/journal.pone.0190093.
  • Riley, T., Collins, D., Karunakaran, R., Kahar, M., Adnan, A., Hassan, SA., Zainul, N., Rustam, F., Wahab, Z., Lee, YY., Ramli, R., Hassan, H., (2018), High prevalence of toxigenic and nontoxigenic Clostridium difficile strains in Malaysia. Journal of Clinical Microbiology, 56(6), article no.e00170-18, DOI: 10.1128/JCM.00170-18.
  • Androga, G., Knight, D., Lim, S., Foster, N., Riley, T., (2018), Antimicrobial resistance in large clostridial toxin-negative, binary toxin-positive Clostridium difficile ribotypes. Anaerobe, 54(2018), 55-60, United Kingdom, Academic Press, DOI: 10.1016/j.anaerobe.2018.07.007.
  • Amy, J., Bulach, D., Knight, D., Riley, T., Johanesen, P., Lyras, D., (2018), Identification of large cryptic plasmids in Clostridioides (Clostridium) difficile. Plasmid, 96-97(2018), 25-38, United States, Academic Press, DOI: 10.1016/j.plasmid.2018.04.001.
  • Roshan, N., Riley, T., Knight, D., Hammer, K., (2018), Effect of natural products on the production and activity of Clostridium difficile toxins in vitro. Scientific Reports, 8(1), Article number 15735, United Kingdom, Nature Publishing Group, DOI: 10.1038/s41598-018-33954-2.
  • Roshan, N., Riley, T., Hammer, K., (2018), Effects of natural products on several stages of the spore cycle of Clostridium difficile in vitro. Journal of Applied Microbiology, 125(3), 710-723, United Kingdom, Wiley-Blackwell Publishing, Inc., DOI: 10.1111/jam.13889.
  • Roshan, N., Hammer, K., Riley, T., (2018), Non-conventional antimicrobial and alternative therapies for the treatment of Clostridium difficile infection. Anaerobe, 49(Feb 2018), 103-111, United Kingdom, Academic Press, DOI: 10.1016/j.anaerobe.2018.01.003.
  • Riley, T., Kimura, T., (2018), The Epidemiology of Clostridium difficile Infection in Japan: A Systematic Review. Infectious diseases and therapy, 7(1), 39-70, United States, Springer Healthcare, DOI: 10.1007/s40121-018-0186-1.
  • Mitchell, B., White, N., Farrington, A., Allen, M., Page, K., Gardner, A., Halton, K., Riley, T., Gericke, C., Paterson, D., Graves, N., Hall, L., (2018), Changes in knowledge and attitudes of hospital environmental services staff: The Researching Effective Approaches to Cleaning in Hospitals (REACH) study. American Journal of Infection Control, 46(9), 980-985, United States, Mosby, Inc, DOI: 10.1016/j.ajic.2018.02.003.
  • Lim, SC., Foster, NF., Elliott, B., Riley, T., (2018), High prevalence of Clostridium difficile on retail root vegetables, Western Australia. Journal of Applied Microbiology, 124(2), 585-590, United Kingdom, Wiley-Blackwell Publishing, Inc., DOI: 10.1111/jam.13653.
  • Lim, S., Androga, G., Knight, D., Moono, P., Foster, N., Riley, T., (2018), Antimicrobial susceptibility of Clostridium difficile isolated from food and environmental sources in Western Australia. International Journal of Antimicrobial Agents, 52(3), 411-415, Netherlands, Elsevier, DOI: 10.1016/j.ijantimicag.2018.05.013.
  • Larcombe, S., Hutton, M., Riley, T., Abud, H., Lyras, D., (2018), Diverse bacterial species contribute to antibiotic-associated diarrhoea and gastrointestinal damage. Journal of Infection, 77(5), 417-426, United Kingdom, W B Saunders Co.Ltd, DOI: 10.1016/j.jinf.2018.06.006.
  • Collins, D., Selvey, L., Celenza, A., Riley, T., (2017), Community-associated Clostridium difficile infection in emergency department patients in Western Australia. Anaerobe, 48(August 2017), 121-125, London, United Kingdom, Academic Press, DOI: 10.1016/j.anaerobe.2017.08.008.
  • Zainul, NH., Ma, ZF., Besari, A., Hassan, SA., Rahman, RA., Collins, D., Hamid, N., Riley, T., Lee, YY., (2017), Prevalence of Clostridium difficile infection and colonization in a tertiary hospital and elderly community of North-Eastern Peninsular Malaysia. Epidemiology and Infection, 145(14), 3012-3019, Cambridge, United Kingdom, Cambridge University Press, DOI: 10.1017/S0950268817002011.
  • Knight, DR., Squire, MM., Collins, D., Riley, T., (2017), Genome Analysis of Clostridium difficile PCR Ribotype 014 Lineage in Australian Pigs and Humans Reveals a Diverse Genetic Repertoire and Signatures of Long-Range Interspecies Transmission. Frontiers in Microbiology, 7(2138), 48, DOI: 10.3389/fmicb.2016.02138.
  • Elliott, B., Androga, G., Knight, DR., Riley, T., (2017), Clostridium difficile infection: Evolution, phylogeny and molecular epidemiology. Infection, Genetics and Evolution, 49(2017), 1-11, Netherlands, Elsevier, DOI: 10.1016/j.meegid.2016.12.018.
  • Collins, D., Gasem, MH., Habibie, TH., Arinton, IG., Hendriyanto, P., Hartana, AP., Riley, T., (2017), Prevalence and molecular epidemiology of Clostridium difficile infection in Indonesia. New Microbes and New Infections, 18(July 2017), 34-37, Bromley, United Kingdom, Elsevier, DOI: 10.1016/j.nmni.2017.04.006.
  • Furuya-Kanamori, L., Riley, T., Paterson, D., Foster, N., Huber, C., Hong, S., Harris-Brown, T., Robson, J., Clements, A., (2017), Comparison of Clostridium difficile Ribotypes Circulating in Australian Hospitals and Communities. Journal of Clinical Microbiology, 55(1), 216-225, American Society for Microbiology, DOI: 10.1128/JCM.01779-16.
  • Cheong, E., Roberts, T., Rattanavong, S., Riley, T., Newton, P., Dance, D., (2017), Clostridium difficile infection in the Lao People’s Democratic Republic: first isolation and review of the literature. BMC Infectious Diseases, 17(September), Article No. 635, London, United Kingdom, BioMed Central Ltd, DOI: 10.1186/s12879-017-2737-6.
  • Moono, P., Lim, SC., Riley, T., (2017), High prevalence of toxigenic Clostridium difficile in public space lawns in Western Australia. Scientific Reports, 7(1 Feb. 2017), Article number 41196, Nature, DOI: 10.1038/srep41196.
  • Putsathit, P., Maneerattanaporn, M., Piewngam, P., Kiratisin, P., Riley, T., (2017), Prevalence and molecular epidemiology of Clostridium difficile infection in Thailand. New Microbes and New Infections, 15(n/a), 27-32, DOI: 10.1016/j.nmni.2016.10.004.
  • Chen, Y., Glass, K., Liu, B., Korda, R., Riley, T., Kirk, M., (2017), Burden of Clostridium difficile infection: Associated hospitalization in a cohort of middle-aged and older adults. American Journal of Infection Control, 45(5), 508-511, Elsevier, DOI: 10.1016/j.ajic.2016.12.006.
  • Furuya-Kanamori, L., Clements, A., Foster, N., Huber, C., Song, S., Harris-Brown, T., Yakob, L., Paterson, D., Riley, T., (2017), Asymptomatic Clostridium difficile colonization in two Australian tertiary hospitals, 2012-2014: prospective, repeated cross-sectional study. Clinical Microbiology and Infection, 23(1), 48.e1-48.e7, Elsevier, DOI: 10.1016/j.cmi.2016.08.030.
  • Collins, D., Putsathit, P., Elliott, B., Riley, T., (2017), Laboratory-based surveillance of Clostridium difficile strains circulating in the Australian healthcare setting in 2012. Pathology, 49(3), 309-313, DOI: 10.1016/j.pathol.2016.10.013.
  • McGovern, AM., Androga, GO., Knight, DR., Watson, MW., Elliott, B., Foster, NF., Chang, BJ., Riley, T., (2017), Prevalence of binary toxin positive Clostridium difficile in diarrhoeal humans in the absence of epidemic ribotype 027. PLoS One, 12(11), article no. e0187658, California, USA, Public Library of Science, DOI: 10.1371/journal.pone.0187658.
  • Chen, Y., Glass, K., Liu, B., Riley, T., Korda, R., Kirk, M., (2017), A population-based longitudinal study of Clostridium difficile infection-related hospitalization in mid-age and older Australians. Epidemiology and Infection, 145(3), 575-582, DOI: 10.1017/S0950268816002260.
  • Putsathit, P., Maneerattanaporn, M., Piewngam, P., Knight, DR., Kiratisin, P., Riley, T., (2017), Antimicrobial susceptibility of Clostridium difficile isolated in Thailand. Antimicrobial Resistance and Infection Control, 6(1), Article no. 58, United Kingdom, BioMed Central Ltd, DOI: 10.1186/s13756-017-0214-z.
  • Roshan, N., Riley, T., Hammer, K., (2017), Antimicrobial activity of natural products against Clostridium difficile in vitro. Journal of Applied Microbiology, 123(1), 92-103, United Kingdom, Wiley-Blackwell Publishing Ltd, DOI: 10.1111/jam.13486.
  • Engelhardt, N., Foster, N., Hong, S., Riley, T., McGechie, D., (2017), Comparison of two environmental sampling tools for the detection of Clostridium difficile spores on hard bathroom surfaces in the hospital setting. Journal of Hospital Infection, 96(3), 295-296, United Kingdom, W.B Saunders Co Ltd, DOI: 10.1016/j.jhin.2017.03.028.
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