Blue light destroys antibiotic-resistant staph infection

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Blue light destroys antibiotic-resistant staph infection

http://news.xinhuanet.com/english/2009-01/30/content_10735134.htm

WASHINGTON, Jan. 29 (Xinhua) -- Two common strains of methicillin-resistant

Staphylococcus aureus, commonly known as MRSA, were virtually eradicated in the

laboratory after being exposed to a wavelength of blue light, according to a

paper published online on Thursday ahead of print in Photomedicine and Laser

Surgery.

Antibiotic-resistant bacterial infections represent an important and increasing

public health threat. At present, fewer than 5 percent of staphylococcal strains

are susceptible to penicillin, while approximately 40 percent to 50 percent of

Staph aureus isolated have developed resistance to newer semisynthetic

antibiotics such as methicillin as well.

Researchers from the New York Institute of Technology had previously

demonstrated that a process called photo-irradiation using 405-nm light destroys

MRSA strains grown in culture. In the current study, the authors exposed

bacterial colonies of MRSA to various doses of 470-nm light, which emits no UV

radiation.

The two MRSA populations studied -- the US-300 strain of CA-MRSA and the IS-853

strain of HA-MRSA -- represent prominent community-acquired and

hospital-acquired strains, respectively.

The authors report that the higher the dose of 470-nm blue light, the more

bacteria were killed. High-dose photo-irradiation was able to destroy 90.4

percent of the US-300 colonies and the IS-853 colonies. The effectiveness of

blue light in vitro suggests that it should also be effective in human cases of

MRSA infection, and particularly in cutaneous and subcutaneous infections.

**It is inspiring that an inexpensive naturally visible wavelength of light can

eradicate two common strains of MRSA. Developing strategies that are capable of

destroying MRSA, using mechanisms that would not lead to further antibiotic

resistance, is timely and important for us and our patients,** says Chukuka S.

Enwemeka, first author of the study.