Biofilm formation by Escherichia coli in hypertonic sucrose media
2009
Kawarai, T.(Nihon Univ., Fujisawa, Kanagawa (Japan). Coll. of Bioresource Sciences) | Furukawa, S. | Narisawa, N. | Hagiwara, C. | Ogihara, H. | Yamasaki, M.
High osmotic environments produced by NaCl or sucrose have been used as reliable and traditional methods of food preservation. We tested, Escherichia coli as an indicator of food-contaminating bacterium, to determine if it can form biofilm in a hyperosmotic enviroument. E. coli K- 12 IAM1264 did not form biofilm in LB broth that contained 1 M NaCl. However, the bacterium formed biofilm in LB broth that contained 1 M sucrose, although the planktonic growth was greatly suppressed. The biofilm, formed on solid surfaces, such as titer-plate well walls and glass slides, solely around the air-liquid interface. Both biofilm forming cells and planktonic cells in the hypertonic medium adopted a characteristic, fat and filamentous morphology with no FtsZ rings, which are a prerequisite for septum formation. Biofilm forming cells were found to be alive based on propidium iodide staining. The presence of 1 M sucrose in the food environment is not sufficient to prevent biofilm formation by E. coli.
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