Enhancing an existing technology, the scientists used photodynamic therapy to kill S. aureus (staph) bacteria in mouse models of skin and soft tissue infections.
This type of bacteria is known to thrive on iron from blood, but the group of scientists note in their study paper that, just like vampires, they are equally deterred by light.
Staph needs iron to grow. "It breaks open the blood cells and grabs the hemoglobin and pulls the iron out," said Eric Skaar, Ph.D., MPH and lead scientist. Other Gram-positive pathogens probably do the same thing. "But the S. aureus systems are by far the most well studied," he added.
According to the scientists’ findings, the molecule, called '882 for short, activates a bacterial enzyme called CgoX, which in turn induces accumulation of a photoreactive molecule called CPIII. When struck by light of a certain wavelength, CPIII produces reactive oxygen species that kill the bacterium.
"Small-molecule activation of CgoX represents a promising strategy for the development of light-based antimicrobial therapies," the researchers concluded this week in the Proceedings of the National Academy of Sciences.
Enhancing photodynamic therapy
Photodynamic therapy has been used for years to treat certain types of cancer, as well as some more severe types of cancer, but it is also know to kill human cells too, causing unwanted side effects, which means it never really took off as a viable treatment.
"Now we have a molecule that only targets the bacterial enzyme in the pathway so you can selectively make bacteria photosensitive," Skaar said.
The group of researchers is now working in collaboration with E. Duco Jansen, Ph.D., professor of Biomedical Engineering, and the Vanderbilt Biophotonics Center in the School of Engineering to develop technologies that can deliver light effectively to infected skin for treatment of a range of associated problems, including acne.