Current antibiotics tend to be broad-spectrum, leading to indiscriminate killing of commensal bacteria and accelerated evolution of drug resistance.
These pitfalls may be avoided with a new antimicrobial approach that imposes “direct evolutionary pressure at the gene level by using efficiently delivered, programmable RGNs [RNA-guided nucleases]”. Known as CRISPR-associated Cas, the system is part of the bacterium’s own defence strategy that triggers cell death or plasmid loss upon detection of genetic signatures associated with virulence or antibiotic resistance.
By manipulating the system, Timothy Lu and colleagues at Massachusetts Institute of Technology were able to disarm genes involved in determining antibiotic resistance and virulence, resulting in the death of more than 99% of previously resistant bacteria, according to research in Nature Biotechnology
(online, 21 September 2014). The team is now testing the approach in mice.