title: Inactivation of bacterial pathogens following exposure to light from a 405-nanometer light-emitting diode array.
abstract: This study demonstrates the susceptibility of a variety of medically important bacteria to inactivation by 405-nm light from an array of light-emitting diodes (LEDs), without the application of exogenous photosensitizer molecules. Selected bacterial pathogens, all commonly associated with hospital-acquired infections, were exposed to the 405-nm LED array, and the results show that both gram-positive and gram-negative species were successfully inactivated, with the general trend showing gram-positive species to be more susceptible than gram-negative bacteria. Detailed investigation of the bactericidal effect of the blue-light treatment on Staphylococcus aureus suspensions, for a range of different population densities, demonstrated that 405-nm LED array illumination can cause complete inactivation at high population densities: inactivation levels corresponding to a 9-log(10) reduction were achieved. The results, which show the inactivation of a wide range of medically important bacteria including methicillin-resistant Staphylococcus aureus, demonstrate that, with further development, narrow-spectrum 405-nm visible-light illumination from an LED source has the potential to provide a novel decontamination method with a wide range of potential applications.
authors.affiliation: The Robertson Trust Laboratory for Electronic Sterilisation Technologies, University of Strathclyde, 204 George Street, Glasgow, Scotland. michellemaclean@eee.strath.ac.uk
authors.forename: Michelle
authors.initials: M
authors.lastname: Maclean
authors.forename: Scott J
authors.initials: SJ
authors.lastname: MacGregor
authors.forename: John G
authors.initials: JG
authors.lastname: Anderson
authors.forename: Gerry
authors.initials: G
authors.lastname: Woolsey
mesh_terms: D003428:Cross Infection / Q000382:microbiology; D004203:Disinfection / Q000379:methods*; D006090:Gram-Negative Bacteria / Q000528:radiation effects*; D006094:Gram-Positive Bacteria / Q000528:radiation effects*; D008027:Light; D050296:Microbial Viability