A Genetic Tool to Attack Drug-Resistant Bacteria
Roughly 700,000 people die per year as a result of an ever-evolving bacteria resistant to antibiotics, known as superbugs. Bacteria are expanding faster than people may expect as they increase immunity against antibiotics due to the overuse of the latter.
Dr. Timothy Lu, an associate professor in biological engineering at MIT, proposes a new approach to tackling the problem. Instead of developing new drugs, Dr. Lu looks forwards to “re-engineering the genetic code that underpins life” as a solution to kill superbugs.
Dr. Lu and his team came up with a biological tool called Crispr-Cas9, which kills superbugs by altering their DNA. Cas9, a natural protein from bacteria, functions as a genetic scalpel paired with a chunk of pre-programmed RNA. The combination will look for a DNA sequence of the resistant bacteria that matches its RNA, and Cas9 will immediately cut off both strands of that DNA sequence. Repair enzymes will then seal the gap with new genetic information to change the genetic code, thus correcting disease-causing mutations.
In order to strictly target drug-resistant genes, Crispr-Cas9 will be paired with bacteriophages, a type of virus that can infect bacteria. Doing so would ensure that healthy and beneficial bacteria will be left alone, Dr. Lu explained.
Existing antibiotics often eliminate bad bacteria alongside good ones, while the Crispr-Cas9 technique would only kill “bad” ones. The old way of killing bacteria enables resistant strains to survive as good bacteria are killed during the process, leaving room for the bad ones to flourish.
However, the use of bacteriophages has yet to be proven safe. Another major concern is that bacteria’s strong adaptability will develop resistance to the Crispr-loaded bacteriophages. Experts also fear unknown risks as scientists use Crispr to modify viruses and bacteria.
According to Dr. Lu, in spite of the desiring outcome that Crispr-Cas9 has promised, it is still far from ready to be actually applied. At the same time, superbugs continue to rapidly evolve and increase resistance. That being said, at least scientists now have a new approach to the problem, as Dr. Lambert, an assistant professor of applied engineering physics at Cornell University, noted: “I am very hopeful that we’ll be able to stay one step ahead.”