Inactivation of Bacterial Pathogens following Exposure to Light from a 405-Nanometer Light-Emitting Diode Array

• DOI: 10.1128/aem.01892-08
• Publication Date: 2009-02-07T09:02:15Z
• Authors: Michelle Maclean; Scott J. MacGregor; John G. Anderson; Gerry Woolsey
• Keywords: 0301 basic medicine; 570; Cross Infection; Microbial Viability; Electrical engineering. Electronics Nuclear engineering; Light; 610; Gram-Positive Bacteria; Microbiology; 3. Good health; Disinfection; 03 medical and health sciences; Gram-Negative Bacteria

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.