Bacteria with Built-in Antibiotic

Microbiologists have identified a novel mechanism of contact inhibition used by certain bacteria to prevent growth of other microorganisms.

Investigators at the University of California, Santa Barbara (USA) have found that some strains of Escherichia coli, including some responsible for human urinary tract infections, contained a bacterial growth-inhibition system that uses direct cell-to-cell contact. While inhibited cells were no longer able to grow, staining techniques showed that the bacteria were still alive.

Results published in the August 19, 2005, issue of Science revealed that inhibition was conditional, dependent upon the growth state of the inhibitory cell and the pili expression state of the target cell. Both a large cell-surface protein (contact-dependent inhibitor A, or CdiA) and two-partner secretion family member, CdiB, were required for growth inhibition.

"It is fascinating that bacteria have developed a system by which one cell can contact another and inhibit its growth,” said senior author Dr. David Low, professor of biology at the University of California, Santa Barbara. "This has potential implications for new antibiotics. If bacteria can do this, then maybe we can do it. This research is in its infancy, but opens the door for exploration of the roles of contact-dependent growth inhibition in urinary tract infections and possibly other diseases.”




Related Links:
University of California, Santa Barbara