High-intensity narrow-spectrum light inactivation and wavelength sensitivity of Staphylococcus aureus

Authors

  • Michelle Maclean,

    1. The Robertson Trust Laboratory for Electronic Sterilisation Technologies, Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow, Scotland
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  • Scott J. MacGregor,

    1. The Robertson Trust Laboratory for Electronic Sterilisation Technologies, Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow, Scotland
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  • John G. Anderson,

    1. The Robertson Trust Laboratory for Electronic Sterilisation Technologies, Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow, Scotland
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  • Gerry Woolsey

    1. The Robertson Trust Laboratory for Electronic Sterilisation Technologies, Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow, Scotland
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  • Editor: Mark Enright

Correspondence: Michelle Maclean, The Robertson Trust Laboratory for Electronic Sterilisation Technologies, Department of Electronic and Electrical Engineering, University of Strathclyde, Royal College Building, 204 George Street, Glasgow, Scotland, G1 1XW, UK. Tel.: +44 0 141 548 2891; fax: +44 0 141 552 5398; e-mail: michellemaclean@eee.strath.ac.uk

Abstract

This study was conducted to investigate the bactericidal effects of visible light on methicillin-sensitive and methicillin-resistant Staphylococcus aureus (MRSA), and subsequently identify the wavelength sensitivity of S. aureus, in order to establish the wavelengths inducing maximum inactivation. Staphylococcus aureus, including MRSA strains, were shown to be inactivated by exposure to high-intensity visible light, and, more specifically, through a series of studies using a xenon broadband white-light source in conjunction with a selection of optical filters, it was found that inactivation of S. aureus occurs upon exposure to blue light of wavelengths between 400 and 420 nm, with maximum inactivation occurring at 405±5 nm. This visible-light inactivation was achieved without the addition of exogenous photosensitisers. The significant safety benefit of these blue-light wavelengths over UV light, in addition to their ability to inactivate medically important microorganisms such as MRSA, emphasises the potential of exploiting these non-UV wavelengths for disinfection applications.

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