Lasers prove effective in killing drug-resistant bacterium

Lasers prove effective in killing drug-resistant bacterium

Lasers are the most versatile of tools: We use them to buy groceries, watch Blu-ray movies and even to map the surface of planets.

We use them for fun, because a Star Wars-style light-saber fight is a blast.

Now scientists are looking at ways lasers can be used to kill bacteria, even those resistant to antibiotics, which are responsible for much human misery.

A recent study from researchers at the Washington University School of Medicine in St. Louis demonstrated that ultrashort-pulse lasers were effective in killing multidrug-resistant bacteria — commonly known as “superbugs” — as well as bacterial spores.

The scientists aimed their lasers at Staphylococcus aureus [staf-fuh-luh-kaa-kuss aw-ree-uhs], which causes skin, lung and other organ infections; Escherichia coli [eh-shr-eee-kee-uh kow-lai], which causes diarrhea, urinary tract and wound infections; and spores of the bacterium Bacillus cereus [buh-si-luhs see-ree-uhs], which causes food poisoning.

The lasers won, killing more than 99.9% of the targeted organisms.

Here’s how it works: Ultrashort-pulse lasers excite the densely packed protein structures contained in viruses and bacteria. The laser shakes the protein structures until their molecular bonds break. Those broken ends quickly latch on to whatever they can find, and often what they find is wrong. The resulting mess disrupts normal protein function.

The lasers, meantime, must be calibrated at a much higher level to harm human cells. Other effective sterilization methods, including heat, chemicals like bleach, or radiation, are often too harmful to use on people.

The researchers believe ultrashort-pulse lasers could be used in the future to sterilize hospitals and surgical areas, patients’ wounds and other biological products like blood or plasma.

But sorry, Dr. Evil, still no progress on attaching laser beams to sharks’ heads.

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