Comparison of UVB and UVC irradiation disinfection efficacies on Pseudomonas Aeruginosa biofilm

Aikaterini Argyraki, M. Markvart, Anne Nielsen, T. Bjarnsholt, L. Bjørndal, Paul Michael Petersen

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Disinfection routines are important in all clinical applications. The uprising problem of antibiotic resistance has driven major research efforts towards alternative disinfection approaches, involving light-based solutions. Pseudomonas
aeruginosa (P. aeruginosa) is a common bacterium that can cause skin, soft tissue, lungs, kidney and urinary tract infections. Moreover, it can be found on and in medical equipment causing often cross infections in hospitals. The objective of this study was to test the efficiency, of two different light-based disinfection treatments, namely UVB and UVC irradiation, on P. aeruginosa biofilms at different growth stages. In our experiments a new type of UV light emitting diodes (LEDs) were used to deliver UV irradiation on the biofilms, in the UVB (296nm) and UVC (266nm) region. The killing rate was studied as a function of dose for 24h grown biofilms. The dose was ramped from 72J/m2 to 10000J/m2. It was shown that UVB irradiation was more effective than UVC irradiation in inactivating P. aeruginosa biofilms. No colony forming units (CFU) were observed for the UVB treated biofilms when the dose was 10000 J/m2 (CFU in control sample: 7.5 x 104
). UVB irradiation at a dose of 20000J/m2 on mature biofilms (72h grown) resulted in a 3.9 log killing efficacy. The fact that the wavelength of 296nm exists in daylight and has such disinfection ability on biofilms gives new perspectives for applications within disinfection at hospitals.
Original languageEnglish
Title of host publicationProceedings of SPIE
Number of pages7
PublisherSPIE - International Society for Optical Engineering
Publication date2016
Article number988730
Publication statusPublished - 2016
EventSPIE Photonics Europe 2016: Biophotonics: Photonic Solutions for Better Health Care - SQUARE Brussels Meeting Centre, Brussels, Belgium
Duration: 3 Apr 20167 Apr 2016
Conference number: 9887


ConferenceSPIE Photonics Europe 2016
LocationSQUARE Brussels Meeting Centre


  • Disinfection
  • Ultraviolet light
  • UVC
  • UVB
  • Light emitting diodes (LEDs)
  • Pseudomonas aeruginosa (P. aeruginosa)
  • Sterilization

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