With bacterial resistance a growing concern, scientists are searching for alternatives to antibiotics. Recently, researchers at the Washington University School of Medicine in St. Louis, Missouri discovered a type of laser that can kill multi-drug resistant, disease-causing bacteria and their spores.

The technology, an ultrashort-pulse laser, emits bursts of light that excite the densely packed protein structures in bacteria and cause breakage of the molecular bonds. The broken ends quickly reattach nonspecifically to whatever is around, resulting in incorrect linkages that prevent normal protein function in the microorganism and, ultimately, bacterial cell death.

In this study, the laser was tested on multi-drug resistant Staphylococcus aureus (MRSA), which causes wound infections, and beta-lactamase-producing Escherichia coli (E. coli), a common cause of urinary tract infections. They also used the laser on a bacterium called Bacillus cereus which causes food poisoning. In all three species, the laser killed over 99.9% of the bacteria.

One of the benefits of the laser as opposed to other means of sterilization is that the light destroys pathogens without harming human cells. Therefore, it’s possible this laser could be used to sterilize wounds or even to disinfect blood during dialysis or prior to transfusion.