Blue Light Can Kill MRSA Infections Researchers Discover

Every few months, reports of MRSA outbreaks hit the newsstands and TV news broadcasts striking fear that someone's teenage college student or hospitalized relative is being exposed to the MRSA, a drug resistant form of the Staphoccocus bacteria. Recently, researchers at New York Institute of Technology completed a study that showed that blue spectral light in the wavelength of 470 nm was over 90% effective in eradicating two strains of MRSA grown in vitro (petri dishes.)

Staphoccocus is a bacteria that commonly grows on skin and mucous membranes. Most strains of "staph" are harmless but Staph aureus is one of the strains that can cause infections in open wounds and boils and more serious infections such as pneumonia, meningitis, or endocarditis. These infections can become life threatening.

Staph infections have become increasingly resistant to current antibiotics and new antibiotics have been unable to keep up as the bacteria mutates. It is estimated that only 5% of all Staphoccocus bacterial infections are susceptible to Methcillian, one of the main first line Penicillin drugs used, and 40-50% of Staph aureus infections are no longer susceptible to Methcillian, such the name MRSA: Methcillian-Resistant Staphoccocus Aureus.

The NYIT study tested one MRSA strain, US-300, that is commonly found in hospital (clinical) environments while the other MRSA strain, IS-853, was "community-acquired" meaning it can be found growing on surfaces such as keyboards, schools and locker rooms. Clinically caused MRSA infections usually affect older people while the median age for community-acquired MRSA infections is 23 years old.

Previous studies of blue spectral light had shown that the lower wavelength of 405 nm was 92-94 % effective in eradicating both strains of MRSA but in that range there is a small exposure of UV light. Visible light wavelength ranges between 400nm where blue light begins to 700 nm where red light is seen. The researchers, wanted to prove that photo irradiation of MRSA bacteria with blue light using a higher wavelength of 470 nm was still effective at killing the bacteria without the UV exposure.

Currently, MRSA and other bacteria are sanitized in hospitals and in wound cleaning using strong CDC approved cleansers which require soaking and/or scrubbing for several minutes to ensure proper bacteria irradiation. Imagine the possibilities if blue light photo radiation could be used to sterilize equipment and treat MRSA infected wounds especially knowing that the treatment does not expose patients to unwanted UV radiation.

In March '09, University of Pennsylvania School of Medicine received a grant of 5.5 million dollars to study the treatment and spread of MRSA infections in households as well as methods to prevent new and reoccurring MRSA infections. One would hope that they have reviewed the NYIT study performed by Drs. Enwemeka, Williams, Enwemeka Hollosi and Yens and plan to utilize the knowledge learned to test photo irradiation using blue spectral light on home and school surfaces since they are frequently the source of community acquired MRSA infections.

Chukuka S. Enwemeka Ph.D, Deborah Williams M.D., Sombiri Enwemeka, Steve Hollosi, D.O. and David Yens Ph.D. Photomedicine and Laser Surgery Volume 27, Number 2, 2009 Mary Ann Liebert, Inc Pp 221-226. Blue 470-nm Light Kills Methicillin-Resistant Staphylococcu aureus (MRSA) in Vitro. Retrieved June 8, 2009 at
http://www.liebertonline.com/doi/pdfplus/10.1089/pho.2008.2413?cookieSet=1

Mary Ann Liebert, Inc./Genetic Engineering News (2009, January 31). Blue Light Destroys Antibiotic-resistant Staph Infection. Retrieved June 8, 2009 at http://www.sciencedaily.com/releases/2009/01/090129131839.htm

News release: Penn Medicine to Research MRSA Infection Recurrence and Household Transmission. (2009, March 4) Retrieved June 8, 2009 at http://www.uphs.upenn.edu/news/News_Releases/2009/03/mrsa-recurrence-research.html