Methicillin-resistant [i]Staphylococcus aureus[i], to call it by its Latin name, is possibly the best known of the so-called superbugs and accounts for over 94,000 invasive infections diagnosed in the U.S. and almost 19,000 deaths.
With traditional antibiotics proving increasingly useless, scientists have been scrambling to come up with a new generation of therapeutic remedies. This is where synthetic biology may offer a potential solution. Synbio, as it’s called, is a technology based on genetic modification that marries biology to engineering.
MRSA is only one of the deadlier diseases that are creating what’s known as “discovery voids,” where pharmaceutical companies are finding it difficult to produce drugs capable of targeting more and more — and stronger — strains of pathogens.
Kyle Cady would like to try to fill some of those voids. Cady is a researcher at Synthetic Genomics Vaccines, Inc, a company whose motto is: ‘New science, new technology, new solutions.’ These days Cady is exploring an old technology and an old solution, but using new science. At a recent gathering of biologists and industry researchers in Boston, Cady described how synthetic biology has resurrected a largely abandoned therapeutic technique used to combat bacterial infections in the 18th Century in Europe and now only practiced in Russia, Poland and Georgia. (It was never approved for use in Western Europe and the U.S.) The therapy is premised on using bacterial phages against bacterial infections. Bacterial phages are viruses that infect bacteria, consuming and killing them.
“The idea is to cause the death of the bacterial host to cure the infection,” Cady told attendees at the Synthetic Biology: Engineering, Evolution & Design (SEED) Conference. “Bacteria phages are extremely common; they thrive on the skin and in the gut without any adverse effects.” And because they adapt so well to our bodies they don’t produce many side effects, unlike antibiotics. They can also be used in much smaller doses than antibiotics. Of course, there’s a downside.
Bacterial phages are customized to only target specific strains of bacteria. Antibiotics, on the other hand, are more like cluster bombs, destroying multiple bacterial strains, some of which are actually beneficial.
To make profitable use of phage therapy you’d need to employ a cocktail of several different kinds of bacterial phages, a cumbersome and not necessarily practical solution. This specificity explains to a large degree why phage therapy hasn’t been taken very seriously until now. “We believe that engineering can address the problem,” Cady says. “By sequencing highly resistant strains and identifying their phage resistant systems we can make mutant phages to target the resistant strains.” Using synthetic biology, scientists can identify the genetic composition of a bacterial pathogen and engineer the phage designed to target it. In this scenario, the most promising way of defeating superbugs like MRSA is by using infectious viruses to kill infectious bacteria. Phages aren’t drugs exactly, but they have drug-like properties, and they may prove better at destroying bugs that antibiotics are no longer effective against.