Cell suicide theory could provide new hope for fighting antibiotic resistance

May 2, 2007 — 

A surprising new theory suggests that some bacterial cells act as "suicide bombers" in cell communities, with the altruistic intention of dying for the common good - and in the process, strengthening other cells that then become resistant to antibiotic drugs.

The finding could aid future research into developing drugs that can skirt the potentially catastrophic problem of bacterial resistance to antibiotics. Kenneth Bayles, of the University of Nebraska Medical Center, writes that "programmed cell death" in bacterial communities is a form of altruism that benefits the larger community of cells and helps strengthen them.

Three years ago, Bayles began growing cells in biofilm to observe how communication between cells, known as "quorum sensing", affects their survival. He observed that when cells are forming a biofilm (a colony of bacteria that contains resistant organisms and is involved in many antibiotic-resistant infections)they perform a function that enables them to leave a unique imprint on the world: Their DNA. A small percentage of cells explode in a process called "lysis," leaving behind a sticky residue that contains DNA and other cellular bioproducts which are then incorporated into the larger cell community to build a stronger biofilm.

Researchers have struggled with the question of why biofilms are extremely resistant to antibiotic drugs. "We don't know why, but we think it's because the cell death function is suppressed in the cells that don't commit suicide, making them tolerant to antibiotics," Dr. Bayles said. "In biofilm infections, if we can turn the cell death function back on, we can make them less resistant to antibiotics. Our research uncovers new targets for antibiotics, which we desperately need."

Source:
University of Nebraska Medical Center