Princeton University researchers have identified two proteins used by E. coli bacteria to form protective outer membranes. This discovery could help scientists find ways to block the membrane-formation process and create new antibiotics to combat diseases like meningitis, gonorrhea and typhoid fever, the researchers said.

E. coli are a type of Gram-negative bacteria, so they have two membranes, inner and outer ones. Without the protection of their outer membrane, Gram-negative bacteria die.

Creating new antibiotics is especially important because bacteria are constantly developing resistance to current drugs, said Thomas Silhavy, a professor in the molecular biology department.

“In the last 10 years, I think only one new drug for Gram-negative bacteria has been put on the market, so they are becoming resistant to all the ones out there,” Silhavy said. “There aren’t as many new drugs in the pipeline for [Gram-negative bacteria] as there are for the Gram-positive ones.”