Set a bug to kill a bug

Engineered bacteria that can detect and kill human pathogens could provide a new way to treat antibiotic-resistant bacteria. Using the tools of synthetic biology, researchers have given bacteria therapeutic properties unseen in any natural strain — although they won't be injected into people any time soon.

"Our study is the first example of how synthetic biology will be useful for fighting bacterial infections," says biochemical engineer Matthew Chang, an author on the paper, which is published today in Molecular Systems Biology.¹

Chang and his team at Nanyang Technological University in Singapore have engineered a strain of Escherichia coli bacteria that attacks Pseudomonas aeruginosa, a bacterium that can cause lethal infections.

Pseudomonas aeruginosa competes with its own species by producing toxic proteins called pyocins. Chang's team exploited this molecular system by giving E. coli the genes for pyocin S5, which kills strains of P. aeruginosa that infect people. Because each pyocin targets only certain bacterial strains, the toxin will not kill other bacteria living in the body.

"Pyocins are the Pseudomonas bacterium's own species-specific antibiotics, so using pyocins...