The new approach, published online in the journal mBio, uses the bacterial immune system, called the CRISPR-Cas system. This immune system protects the bacteria by creating strands of RNA called CRISPR RNAs, which match the DNA of the invader and then unleash proteins to cut the invader's DNA.
Researchers devised a way to make these CRISPR RNAs target the DNA sequences of the bacteria, causing bacterial suicide when the Cas proteins begin to attack the bacteria's DNA.
“In lab testing, we found that this approach removes the targeted bacteria,” said Dr. Chase Beisel, an assistant professor at NC State. “We’re still trying to understand precisely how severing the DNA leads to elimination of the bacteria."
They were able to target the precise bacteria they wanted to kill, and eliminated Salmonella in a culture without affecting good bacteria. They took this targeted approach to the next level by killing one strain of a species without affecting other strains.
Beisel said that “by targeting specific DNA strands through the CRISPR-Cas system, we’re able to bypass the mechanisms underlying the many examples of antibiotic resistance.”