Researchers have used molecules involved in precise gene editing to selectively remove specific bacterial strains from mixed cultures, based on the microbes' DNA sequences.

The CRISPR gene-editing system uses RNA molecules from bacterial immune systems that recognize and cut foreign DNA. Chase Beisel and his colleagues at North Carolina State University in Raleigh engineered these molecules to target DNA sequences from individual strains of Escherichia coli and Salmonella in pure and mixed cultures. They showed that their strategy could distinguish between strains sharing more than 99% of their genetic content, and could remove specific bacteria.

This approach could one day lead to the development of antibiotics that pinpoint harmful bacteria and leave beneficial ones alone, the authors say.

mBio 5, e00928-13 (2014)