School of Pathology and Laboratory Medicine

Clostridium difficile

Clostridium difficile is a spore-forming, anaerobic Gram positive bacterium that can cause antibiotic-associated diarrhoea.

Professor Tom Riley has been researching this organism for over 20 years. Specific areas of interest include;

  • Epidemiology of C. difficile infection
  • Toxin production by C. difficile

Recent publications


  • Eyre DW, Tracey L, Elliott B, Slimings C, Huntington PG, Stuart RL, Korman TM, Kotsiou G, McCann R, Griffiths D, Fawley WN, Armstrong P, Dingle KE, Walker AS, Peto TE, Crook DW, Wilcox MH, Riley TV. 2015. Emergence and spread of predominantly community-onset Clostridium difficile PCR ribotype 244 infection in Australia, 2010 to 2012. Euro Surveill. 20:21059.
  • Mackin KE, Elliot B, Kotsanas D, Howden BP, Carter GP, Korman TM, Riley TV, Rood JI, Jenkin GA, Lyras D. 2015 May 2. Molecular characterization and antimicrobial susceptibilities of Clostridium difficile clinical isolates from Victoria, Australia. Anaerobe 34:80-83
  • Wales SM, Hammer KA, King AM, Tague AJ, Lyras D, Riley TV, Keller PA, Pyne SG. 2015 May. Binaphthyl-1,2,3-triazole peptidomimetics with activity against Clostridium difficile and other pathogenic bacteria. Org Biomol Chem. 28;13(20):5743-56.
  • Collins DA, Elliott B, Riley TV. 2015 Apr. Molecular methods for detecting and typing of Clostridium difficile. Pathology. 47(3):211-8.
  • Androga GO, McGovern AM, Elliott B, Chang BJ, Perkins TT, Foster NF, Riley TV. 2015 Mar. Evaluation of the Cepheid Xpert C. difficile/Epi and meridian bioscience illumigene C. difficile assays for detecting Clostridium difficile ribotype 033 strains. J Clin Microbiol. 53(3):973-5. 
  • Furuya-Kanamori L, McKenzie SJ, Yakob L, Clark J, Paterson DL, Riley TV, Clements AC. 2015 Mar. Clostridium difficile infection seasonality: patterns across hemispheres and continents - a systematic review. PLoS One. 16;10(3):e0120730.
  • Furuya-Kanamori L, Stone JC, Clark J, McKenzie SJ, Yakob L, Paterson DL, Riley TV, Doi SA, Clements AC. 2015 Feb. Comorbidities, Exposure to Medications, and the Risk of Community-Acquired Clostridium difficile Infection: a systematic review and meta-analysis. Infect Control Hosp Epidemiol. 36(2):132-41.
  • Putsathit P, Morgan J, Bradford D, Engelhardt N, Riley TV. 2015 Feb. Evaluation of the BD Max Cdiff assay for the detection of toxigenic Clostridium difficile in human stool specimens. Pathology. 47(2):165-8.
  • Knight DR, Squire MM, Riley TV. 2015 Jan. Nationwide surveillance study of Clostridium difficile in Australian neonatal pigs shows high prevalence and heterogeneity of PCR ribotypes. Appl Environ Microbiol. 81(1):119-23.
  • Putsathit P, Kiratisin P, Ngamwongsatit P, Riley TV. 2015 Jan. Clostridium difficile infection in Thailand. Int J Antimicrob Agents. 45(1):1-7.


  • Huber CA, Hall L, Foster NF, Gray M, Allen M, Richardson LJ, Robson J, Vohra R, Schlebusch S, George N, Nimmo GR, Riley TV, Paterson DL. 2014 Dec. Surveillance snapshot of Clostridium difficile infection in hospitals across Queensland detects binary toxin producing ribotype UK 244. Commun Dis Intell Q Rep. 38(4):E279-84.
  • Elliott B, Dingle KE, Didelot X, Crook DW, Riley TV. 2014 Nov. The complexity and diversity of the Pathogenicity Locus in Clostridium difficile clade 5. Genome Biol Evol. 6(12):3159-70.
  • Knight DR, Squire MM, Riley TV. 2014 Nov. Laboratory detection of Clostridium difficile in piglets in Australia. J Clin Microbiol. 52(11):3856-62.
  • Manzo CE, Merrigan MM, Johnson S, Gerding DN, Riley TV, Silva J Jr, Brazier JS. 2014 Aug. International typing study of Clostridium difficile. Anaerobe. 28:4-7.
  • Furuya-Kanamori L, Robson J, Soares Magalhães RJ, Yakob L, McKenzie SJ, Paterson DL, Riley TV, Clements ACA. 2014. A population-based spatio-temporal analysis of Clostridium difficile infection in Queensland, Australia over a 10-year period. J. Infect. 69:447-455.
  • Foster NF, Riley TV. 2014. Clostridium difficile infection in Australia. Microbiol. Aus. 35:26-28
  • Foster NF, Collins DA, Ditchburn SL, Duncan CN, van Schalkwyk JW, Golledge CL, Keed ABR, Riley TV. 2014. Epidemiology of Clostridium difficileinfection in two tertiary-care hospitals in Perth, Western Australia: a cross-sectional study. New Microb. New Infect. 2:64-71
  • Hart J, Putsathit P, Knight DR, Sammels L, Riley TV, Keil A. 2014. Clostridium difficile infection diagnosis in a paediatric population: comparison of methodologies. Eur J Clin Microbiol Infect Dis. 33:1555-1564.
  • Manzo CE, Merrigan MM, Johnson S, Gerding DN, Riley TV, Silva Jr J, Brazier JS. 2014. International typing study of Clostridium difficile. Anaerobe 28:4-7


  • Squire MM, Carter GP, Mackin KE, Chakravorty A, Noren T, Elliott B, Lyras D, Riley TV. 2013. Novel molecular type of Clostridium difficile in neonatal pigs, Western Australia. Emerg Infect Dis. 19:790-792
  • Lim SK, Stuart RL, Mackin KE, Carter GP, Kotsanas D, Francis MJ, Easton M, Dimovski K, Elliott B, Riley TV, Hogg G, Paul E, Korman TM, Seemann T, Stinear TP, Lyras D, Jenkin GA. 2014. Emergence of a Ribotype 244 Strain of Clostridium difficile Associated With Severe Disease and Related to the Epidemic Ribotype 027 Strain. Clin. Infect. Dis. 58:1723-1730
  • Lee JH, Lee Y, Lee K, Riley TV, Kim H. 2014. The changes of PCR ribotype and antimicrobial resistance of Clostridium difficile in a tertiary care hospital over 10 years. J. Med. Microbiol. 63:819-823
  • Slimings C, Armstrong P, Beckingham WD, Bull AL, Hall L, Kennedy KJ, Marquess J, McCann R, Menzies A, Mitchell BG, Richards MJ, Smollen PC, Tracey L, Wilkinson IJ, Wilson FL, Worth LJ, Riley TV. 2014. Increasing incidence of Clostridium difficile infection, Australia, 2011-2012. Med. J. Aust. 200:272-276
  • Dingle KE, Elliott B, Robinson E, Griffiths D, Eyre DW, Stoesser N, Vaughan A, Golubchik T, Fawley WN, Wilcox MH, Peto TE, Walker AS, Riley TV, Crook DW, Didelot X. 2014. Evolutionary history of the Clostridium difficile pathogenicity locus. Genome Biol. Evol. 6:36-52
  • Slimings C and Riley TV. 2014 Antibiotics and hospital-acquired Clostridium difficile infection: update of systematic review and meta-analysis. J. Antimicrob. Chemother.  69: 881-891.
  • Tan XQ, Verrall AJ, Jureen R, Riley TV, Collins DA, Lin RT, Balm MN, Chan D, Tambyah PA. 2014. The emergence of community-onset Clostridium difficile infection in a tertiary hospital in Singapore: a cause for concern. Int. J. Antimicrob. Agents 43:47-51.
  • Goh S, Hussain H, Chang BJ, Emmett W, Riley TV, Mullany P. 2013. Phage varphiC2 mediates transduction of Tn6215, encoding erythromycin resistance, between Clostridium difficile strains. MBio 4:e00840-00813
  • Yakob L, Riley TV, Paterson DL, Clements AC. 2013. Clostridium difficile exposure as an insidious source of infection in healthcare settings: an epidemiological model. BMC Infect. Dis. 13:376 
  • Friedman ND, Pollard J, Stupart D, Knight DR, Khajehnoori M, Davey EK, Parry L, Riley TV. 2013. Prevalence of Clostridium difficile colonization among healthcare workers. BMC Infect. Dis. 13:459.
  • De Almeida MN, Heffernan H, Dervan A, Bakker S, Freeman JT, Bhally H, Taylor SL, Riley TV, Roberts SA. 2013. Severe Clostridium difficile infection in New Zealand associated with an emerging strain, PCR-ribotype 244. N. Z. Med. J. 126:9-14
  • Boseiwaqa LV, Foster NF, Thean SK, Squire MM, Riley TV, Carson KC. Comparison of ChromID C. difficile agar and cycloserine-cefoxitin-fructose agar for the recovery of Clostridium difficile. Pathology. 2013 Jul 11. 45(5):495-500.
  • Knight DR, Riley TV. Prevalence of Clostridium difficile gastrointestinal carriage in Australian sheep and lambs. Appl Environ Microbiol. 2013 Jul 12. [Epub ahead of print]. PMID: 23851101.
  • Carson KC, Boseiwaqa LV, Thean SK, Foster NF, Riley TV. Isolation of Clostridium difficile from faecal specimens - a comparison of ChromID C. difficile agar and cycloserine cefoxitin fructose agar. J Med Microbiol. 2013 Apr 11. [Epub ahead of print]. PMID: 23579394.
  • Collins DA, Hawkey PM, Riley TV. Epidemiology of Clostridium difficile infection in Asia. Antimicrob Resist Infect Control. 2013 Jul 1;2(1):21.
  • He M, Miyajima F, Roberts P, Ellison L, Pickard DJ, Martin MJ, Connor TR, Harris SR, Fairley D, Bamford KB, D'Arc S, Brazier J, Brown D, Coia JE, Douce G, Gerding D, Kim HJ, Koh TH, Kato H, Senoh M, Louie T, Michell S, et al. Emergence and global spread of epidemic healthcare-associated Clostridium difficile. Nat Genet. 2013 Jan;45(1):109-13.
  • Huber CA, Foster NF, Riley TV, Paterson DL. Clostridium difficile typing methods: Challenges for Standardization. J Clin Microbiol. 2013 Jun 19. [Epub ahead of print. PMID: 23784128
  • Knight DR, Thean S, Putsathit P, Fenwick S, Riley TV. Cross-sectional study reveals high prevalence of Clostridium difficile non-PCR ribotype 078 strains in Australian veal calves at slaughter. Appl Environ Microbiol. 2013 Apr;79(8):2630-5.
  • Squire MM, Carter GP, Mackin KE, Chakravorty A, Norén T, Elliott B, Lyras D, Riley TV. Novel molecular type of Clostridium difficile in neonatal pigs, Western Australia. Emerg Infect Dis. 2013 May;19(5):790-2.


  • Squire MM, Riley TV. Clostridium difficile Infection in Humans and Piglets: A 'One Health' Opportunity. Curr Top Microbiol Immunol. 2012 Jun 14.
  • Hensgens MP, Keessen EC, Squire MM, Riley TV, Koene MG, de Boer E, Lipman LJ, Kuijper EJ; European Society of Clinical Microbiology and Infectious Diseases Study Group for Clostridium difficile (ESGCD). Clostridium difficile infection in the community: a zoonotic disease? Clin Microbiol Infect. 2012 Jul;18(7):635-45.
  • Foster NF, Riley TV. Improved recovery of Clostridium difficile spores with the incorporation of synthetic taurocholate in cycloserine-cefoxitin-fructose agar (CCFA). Pathology. 2012 Jun;44(4):354-6.
  • Stabler RA, Dawson LF, Valiente E, Cairns MD, Martin MJ, Donahue EH, Riley TV, Songer JG, Kuijper EJ, Dingle KE, Wren BW. Macro and micro diversity of Clostridium difficile isolates from diverse sources and geographical locations. PLoS One. 2012;7(3):e31559.
  • Sathyendran V, Riley TV, Roberts SA, Freeman JT. Mycotic abdominal aortic aneurysm caused by toxigenic Clostridium difficile. Anaerobe. 2012 Jun;18(3):270-2.


  • Ferguson JK, Cheng AC, Gilbert GL, Gottlieb T, Korman T, McGregor A, Richards M, Roberts S, Robson J, Van Gessel H, Riley TV. Clostridium difficile laboratory testing in Australia and New Zealand: national survey results and Australasian Society for Infectious Diseases recommendations for best practice. Pathology. 2011 Aug;43(5):482-7.
  • Richards M, Knox J, Elliott B, Mackin K, Lyras D, Waring LJ, Riley TV. Severe infection with Clostridium difficile PCR ribotype 027 acquired in Melbourne, Australia. Med J Aust. 2011 Apr 4;194(7):369-71.
  • Cheng AC, Ferguson JK, Richards MJ, Robson JM, Gilbert GL, McGregor A, Roberts S, Korman TM, Riley TV; Australasian Society for Infections Diseases. Australasian Society for Infectious Diseases guidelines for the diagnosis and treatment of Clostridium difficile infection. Med J Aust. 2011 Apr 4;194(7):353-8.
  • Thean S, Elliott B, Riley TV. Clostridium difficile in horses in Australia--a preliminary study. J Med Microbiol. 2011 Aug;60(Pt 8):1188-92.
  • Elliott B, Squire MM, Thean S, Chang BJ, Brazier JS, Rupnik M, Riley TV. New types of toxin A-negative, toxin B-positive strains among clinical isolates of Clostridium difficile in Australia. J Med Microbiol. 2011 Aug;60(Pt 8):1108-11.

2010 and earlier

  • Clements AC, Magalhães RJ, Tatem AJ, Paterson DL, Riley TV. Clostridium difficile PCR ribotype 027: assessing the risks of further worldwide spread. Lancet Infect Dis. 2010 Jun;10(6):395-404.
  • Elliott B, Reed R, Chang BJ, Riley TV. Bacteremia with a large clostridial toxin-negative, binary toxin-positive strain of Clostridium difficile. Anaerobe. 2009 Dec;15(6):249-51.
  • Riley TV, Thean S, Hool G, Golledge CL. First Australian isolation of epidemic Clostridium difficile PCR ribotype 027. Med J Aust. 2009 Jun 15;190(12):706-8.
  • Riley TV. Is Clostridium difficile a threat to Australia's biosecurity? Med J Aust. 2009 Jun 15;190(12):661-2.
  • Riley TV, Huovinen P. Infection control measures to limit the spread of Clostridium difficile. Clin Microbiol Infect. 2008 May;14 Suppl 5:1.
  • Kim H, Riley TV, Kim M, Kim CK, Yong D, Lee K, Chong Y, Park JW. Increasing prevalence of toxin A-negative, toxin B-positive isolates of Clostridium difficile in Korea: impact on laboratory diagnosis. J Clin Microbiol. 2008 Mar;46(3):1116-7.
  • Elliott B, Chang BJ, Golledge CL, Riley TV. Clostridium difficile-associated diarrhoea. Intern Med J. 2007 Aug;37(8):561-8.
  • Goh S, Ong PF, Song KP, Riley TV, Chang BJ. The complete genome sequence of Clostridium difficile phage phiC2 and comparisons to phiCD119 and inducible prophages of CD630. Microbiology. 2007 Mar;153(Pt 3):676-85.