JHIBRG:Abstract Mar 20 2008

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Collective behavior of bacteria at high densities

An amazing degree of resistance of bacterial urinary tract infections has recently been ascribed to the ability of E. coli cells to invade the host epithelial cells lining the lumens within the urinary tract thus escaping noxious substances present in the extracellular environment. Moreover, inside the epithelial cells, pathogenic E. coli can form biofilm-like ‘pod’ structures reaching very high densities (Anderson et al. 2003). Upon growing into pods, cells ultimately can exit the host cells by as yet unknown mechanisms and then re-infect other cells re-initiating the growth-infection cycle. Although previous studies focused on the molecular mechanisms in adaptive behavior of bacteria within the host cells, the mechanical aspect of bacterial colony growth has not been fully investigated. Therefore, we decided to study the mechanical stress generated within growing biofilm-like structures. The microfluidic chips provide an alternative to conventional bacterial study by mimicking the environment of host system present in in vivo bacterial infection, during which E.coli cells invade epithelial cells and proliferate inside them to very high densities (Anderson et al. 2004). We will study in particular, the dynamic E.coli stress response activation during formation of high density colonies and application of physical stress by dividing cells onto the confining boundaries. It will provide further insight into how bacterial cells can infiltrate, colonize and finally break away from host epithelial cells, potentially suggesting ways to combat E.coli infections.

Anderson, G. G., et al. (2004). Trends Microbiol 12(9): 424-30.

Anderson, G. G., et al. (2003). Science 301(5629): 105-7.