Like firemen fighting fire with fire, researchers at the University of Illinois and the University of Massachusetts at Amherst have found a way to fool a bacteria's evolutionary machinery into programming its own death.
"The basic idea is for an antimicrobial to target something in a bacteria that, in order to gain immunity, would require the bacteria to kill itself through a suicide mutation," said Gerard Wong, a professor of materials science and engineering, of physics, and of bioengineering at the U. of I.
Wong is corresponding author of a paper accepted for publication in the Proceedings of the National Academy of Sciences . The paper is to be posted this week on the journal's Web site.
The researchers show that a synthetic "hole punching" antimicrobial depends on the presence of phosphoethanolamine, a cone-shaped lipid found in high concentrations within Gram-negative bacterial membranes. Although PE lipids are commandeered to kill the bacteria, without the lipids the bacteria would die, also.
"It's a Catch-22," Wong said. "Some mutations bacteria can tolerate, and some mutations they cannot tolerate. In this case, the bacteria would have to go through a mutation that would kill it, in order to be immune to these antimicrobials."
In their work, the researchers compared the survival of the bacterium Escherichia coli with that of a mutant strain of E. coli, which lacked PE lipids in its membrane. The fragile PE-deficient mutant strain out-survived the normal, healthy bacteria, when exposed to a "hole punching" synthetic antibiotic.