Evidence of Resistance Development by Staphylococcus aureus to an In Vitro, Multiple Stage Application of 405 nm Light from a Supraluminous Diode Array
Photomedicine and Laser Surgery
J. Stephen Guffey, PT, EdD, William Payne, MS, ASCP(MT), Tyler Jones, MSEd, CSCS, and Kyle Martin, BA
4/8/2013 - J. Stephen Guffey, William Payne, Tyler Jones, and Kyle Martin. Photomedicine and Laser Surgery. April 2013, 31(4): 179-182. doi:10.1089/pho.2012.3450.
Objective:
The aim of this study was to determine whether Staphylococcus aureus could develop a resistance to 405 nm light.
Background data:
Research indicates that certain wavelengths and treatment parameters of light promote growth of bacteria; however, our earlier work indicated that blue light effectively inactivates growth of S. aureus in vitro.
Methods:
S. aureus was tested because of its frequent isolation from skin infections and wounds. The organism was treated with 405 nm light from supraluminous diodes at a dose of 9 J/cm2.
Results:
As anticipated, blue light produced a significant (p≤0.05) inactivation of S. aureus growth. Subsequent applications of blue light to subcultured generations of S. aureus were increasingly effective through four stages (generations). Beginning with stage five, a decrease in effectiveness (resistance) was observed.
Conclusions:
Appropriate doses of 405-nm blue light inhibit the growth of S. aureus in vitro. This research does suggest that S. aureus may be capable of developing resistance to blue light irradiation.