Scientists found new gene-editing method to kill superbugs

MIT engineers developed a new gene-editing system that can selectively kill bacteria carrying harmful genes which is responsible for conferring antibiotic resistance. Most antibiotics work by interfering with crucial functions such as cell division or protein synthesis. However, some bacteria, including the formidable MRSA (methicillin-resistant Staphylococcus aureus) and CRE (carbapenem-resistant Enterobacteriaceae) organisms, have evolved to become virtually untreatable with existing drugs. Scientists designed their RNA guide strands to target genes for antibiotic resistance, including the enzyme NDM-1, which allows bacteria to resist a broad range of beta-lactam antibiotics, including carbapenems. The genes encoding NDM-1 and other antibiotic resistance factors are usually carried on plasmids – circular strands of DNA separate from the bacterial genome which makes it easier for them to spread through populations. Researchers were able to specifically kill more than 99 per cent of NDM-1-carrying bacteria, while antibiotics to which the bacteria were resistant did not induce any significant killing. They also successfully targeted another antibiotic resistance gene encoding SHV-18, a mutation in the bacterial chromosome providing resistance to quinolone antibiotics, and a virulence factor in enterohemorrhagic E coli. The researchers showed that the CRISPR system could be used to selectively remove specific bacteria from diverse bacterial communities based on their genetic signatures, thus opening up the potential for “microbiome editing” beyond antimicrobial applications.