4/21/19 Mohamed Seleem

Professor Mohamed Seleem poses in a lab. He and his team discovered that blue light could treat superbug infections.

A Purdue professor is fighting the growing antibiotic resistance that has given rise to superbugs with a new tool that weakens the bacteria.

Superbugs kill around 23,000 people in the U.S. and infect over two million people a year, according to the National Institute of Health. Mohamed Seleem‘s new method is currently effective against methicillin-resistant Staphylococcus aureus, which can cause sepsis and death. In cases of diabetic ulcers, the MRSA-infected area requires amputation.

Seleem, a professor of microbiology, and Ji-Xin Cheng, a former Purdue professor of biomedical engineering, discovered that MRSA is weakened when exposed to blue light.

“Pigments in bacteria are important for membrane integrity in the host,” Seleem said. “By exposing the bacteria to blue light, we can remove the pigment.”

Removing the pigment renders the MRSA defenseless to mild antiseptics.

Some wavelengths of light, like ultraviolet, can kill the bacteria altogether. However, ultraviolet light is harmful, unlike blue light, according to Seleem.

“That specific wavelength is not toxic to your skin,” Seleem said. “It doesn’t kill anything in the bacteria and just removes this pigment specifically.”

Seleem’s tool is currently a box emitting blue light over a specified area, but Seleem and his colleagues are working toward sizing the device down for future use.

“We are aiming hopefully, in the future, that that box will be kind of a small flashlight,” Seleem said. “So that people may just use it as a flashlight over the wound.”

In an experiment with lab-infected mice, blue light was more effective than antibiotics traditionally used to treat the infection. Cheng is trying to arrange clinical trials to move this invention into human testing.

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