Blue light therapy could cure MRSA infections that resist antibiotics

Knowing that some methicillin-resistant Staphylococcus aureus (MRSA) infections can be life-threatening, a team of researchers at Purdue University (West Lafayette, IN) and Boston University (Boston, MA) has discovered that exposing MRSA to blue light can render it defenseless against antiseptics as mild as hydrogen peroxide. The light therapy tool could help clinicians to avoid taking chances with multidrug combinations, as well as eliminate the need for them to determine which drug to prescribe, which can take too much time.

"This new tool can treat any superficial wound infected with MRSA, which are typically very difficult to treat," says Mohamed Seleem, a professor of microbiology at Purdue's College of Veterinary Medicine who researches antimicrobial resistance and infectious disease. The portable device, which Seleem hopes will be available commercially in the next few years, resembles a small box with a hole for light to come through, which contains the light to the wound.

Related: Photodynamic therapy method may combat MRSA infection

Some bacteria, including certain strains of staph, produce pigments. These pigments are associated with the organism's ability to damage the host and by reducing the pigment, it is possible to reduce the organism's activity in the body—a practice is known as photobleaching.

After achieving promising results in vitro, the researchers exposed mice with MRSA-infected wounds to different wavelengths of light. The infections responded especially well to light in the blue region, and combined with a low-concentration hydrogen peroxide, were reduced significantly.

Full details of the work appear in the journal Advanced Science.