Enhanced decontamination of C. difficile spores on surfaces via the synergistic action of 405nm light and disinfectants

Sian Moorhead, Michelle MacLean, John E Coia, Scott J MacGregor, John G Anderson

Research output: Contribution to conferencePosterpeer-review

61 Downloads (Pure)


The ability of C. difficile to form spores which can survive for prolonged periods causes significant environmental contamination problems. 405nm light has wide antimicrobial activity against vegetative bacteria, and is being developed for environmental decontamination within hospitals. As expected, spores are more resilient to inactivation. This study aims to establish whether spore susceptibility can be enhanced by combining 405nm light with low concentration chlorinated disinfectants: sodium hypochlorite, Actichlor and Tristel. Spore suspensions were seeded onto surfaces including PVC, stainless steel and vinyl flooring. Disinfectant was added to the surface, and the samples were then exposed to 405nm light at irradiances of ~0.2-225 mWcm-2. Control samples were exposed to 405nm light alone, and disinfectants alone, to establish the sporicidal activity of each agent, and to demonstrate the synergistic effect when combined.
Results demonstrated increased sporicidal activity of 405nm light and low-concentration sodium hypochlorite and Actichlor against C. difficile seeded on vinyl flooring and PVC surfaces, with approximately 3-log10 reductions achieved with up to 66% lower doses than achieved with light alone. Tristel demonstrated limited synergy on vinyl and PVC, whilst all three disinfectants demonstrated minimal synergy on stainless steel. Results are also reported for lower intensity light, as used in the clinical environment. In conclusion, the sporicidal efficacy of 405nm light is enhanced when used alongside chlorinated disinfectants. Further research could potentially lead to the use of lower strength chlorinated disinfectants in combination with 405nm light to provide enhanced decontamination of C. difficile spores in the clinical environment.

Original languageEnglish
Number of pages1
Publication statusPublished - 24 Mar 2016
EventThe Microbiology Society Annual Conference - Arena and Convention Centre (ACC), Liverpool, United Kingdom
Duration: 21 Mar 201624 Mar 2016


ConferenceThe Microbiology Society Annual Conference
Country/TerritoryUnited Kingdom
Internet address


  • C. difficile
  • decontamination
  • disinfectants


Dive into the research topics of 'Enhanced decontamination of C. difficile spores on surfaces via the synergistic action of 405nm light and disinfectants'. Together they form a unique fingerprint.

Cite this