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This New Gene Editing Technique Could Turn The Tide on Antibiotic Resistance

In a proof-of-concept, researchers used CRISPR/Cas to erase genes that make E. Coli resistant to antibiotics.
An electron micrograph of bacteriophages attached to a bacterial cell. Image: Dr Graham Beards/Wikipedia

Back in the bad old days, say before 1940 or so, the ubiquitous presence of nasty bacteria made life a dicey affair. If you were unlucky, something as innocuous as a paper cut could lead to infection and a painful death. All that began to change when Scottish biologist Alexander Fleming noticed that an outbreak of mould on his bacterial cultures were killing the little buggers; when he isolated the active ingredient from the mould, penicillin was born—the first antibiotic.

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Since Fleming's serendipitous discovery, a whole host of antibiotics have been developed. But many have met their match in bacteria which have evolved to become resistant to the drugs that are trying to kill them. The rise of antibiotic resistance is no trivial matter: the Centers for Disease Control estimates that in the US, at least two million people are infected annually with these hardy bugs and about 23,000 will die.

But a new technique developed by Israeli researchers at Tel Aviv University could create a new class of antibiotic. It works by slashing out the genes that confer drug resistance to the bacteria with the effectiveness of a Seal Team Six surgical strike, and was detailed in a new paper published on May 18 in the journal Proceedings of the National Academy of Sciences (PNAS).

The researchers used a type of virus called a lambda phage which is capable of infecting E. Coli bacteria but not the eukaryotic cells that humans are made of. The virus infects antibiotic-resistant bacteria and injects them with a piece of DNA that codes for a CRISPR-Cas enzyme.

You may have heard of CRISPR-Cas before; it's a molecular tool that can edit genetic material with startling accuracy.

In this experiment, the CRISPR-Cas enzyme targets the bacteria's beta-lactamase genes, erasing them from the bacterial genome. Beta-lactamase allows the bacteria to conquer certain types of antibiotics in its environment—including penicillin and cephamycin. With those genes wiped off the map, the bacteria is re-sensitized to antibiotics, and is soon laid to waste.

The research is more a proof-of-concept than an actual therapy, but it's a useful one. Lambda phage only infects E. coli bacteria, but other viral assassins could be used to attack any of the myriad microbial nasties that might threaten us with their inevitable drug resistance. The authors of the research suggest one particularly useful place to spray a suspension of bacteria-killing viruses would be on surfaces in medical institutions, which are rife with killer bugs.

In any case, the research is a welcome development: in the evolutionary arms race between us and resistant bacteria, fast-evolving microbes are always going to have the upper hand.