Friday, 26 April 2013

Bacterial survival in water systems

New research has looked at the ways in which  waterborne bacteria can colonize rough surfaces, even those that have been designed to resist water.

The research has looked at Escherichia coli, which has many flagella that stick out in all directions. The researchers found that these tails can act as biological grappling hooks, reaching far into nanoscale crevices and latching the bacteria in place.

E. coli are equipped with two types of appendages: pili, which are short, sticky hairs, and the whip-like flagella, which are often twice as long as the bacterium itself. Pili had previously been recognized as playing a critical role in the formation of biofilms. These short hairs, up to only a micron in length in E. coli, can stick to surfaces temporarily, while the bacteria secrete a thick slime that holds them permanently in place.


Flagella also contribute to adhesion on rough surfaces, where the pili would have access to fewer attachment points.

The research could be important to those concerned about biofilms. Biofilms pose problems for the food industry, water treatment, ship maintenance, and other industries where slime can clog pipes and filters, corrode metal, or cause contamination.

The implications from the study are that antibacterial materials should incorporate both structural and chemical deterrents to bacterial attachment. The surface chemistry of antibacterial materials appears to be just as important as the topography.
 The research was carried out at Harvard University. The findings have been published the Proceedings of the National Academy of Sciences (PNAS) "Bacterial flagella explore microscale hummocks and hollows to increase adhesion."

  Posted by Tim Sandle