Infectious disease 4

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hemorrhagic E. coli colonizing the small bowel they sit on pedestals - which are
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Terms in this set (24)
All materials that can be transmitted laterally and can transmit virulence factors, if they move into a commensal e. coli they can change it froman avirulent version to a now virulent pathogenic E. coliEvolution of pathogenesis in E. Coli was through a process oflateral acquisition of virulence factorsmaterial that can be laterally transferred can includeTransposons, PAI- pathogenicity islands, Phage, PlasmidsThe E. coli type III secretion (T3S) system is encoded on a 36-kbp laterally-acquired pathogenicity island called thelocus of enterocyte effacement, LEE-LEE is required forcolonization of the gut by hemorrhagic E. coliLEE includesstructural and regulatory genes for T3Sloss of LEE genes leads toreduced colonizationEnterocyte -epithelial cell of small bowelStructure of T3S systems ismostly conservedE. coli mutated for LEE and T3S aredefective in colonizationHemorrhagic E. coli colonization requires interaction between theafimbrial adhesin intimin, and the cell receptor Tir—translocated intimin receptorBoth intimin adhesin and Tir receptor are encoded byE. coli!TIR - isa dimer that is imbedded in host membraneHow is the receptor encoded by e. coli but ends up imbedded in the host membrane?It uses a t3S to translocate TIR from inside of E. coli into host intestinal cells