Role of tir and intimin in the virulence of rabbit enteropathogenic Escherichia coli serotype O103:H2.

ABSTRACT Attaching and effacing (A/E) rabbit enteropathogenic Escherichia coli (REPEC) strains belonging to serogroup O103 are an important cause of diarrhea in weaned rabbits. Like human EPEC strains, they possess the locus of enterocyte effacement clustering the genes involved in the formation of the A/E lesions. In addition, pathogenic REPEC O103 strains produce an Esp-dependent but Eae (intimin)-independent alteration of the host cell cytoskeleton characterized by the formation of focal adhesion complexes and the reorganization of the actin cytoskeleton into bundles of stress fibers. To investigate the role of intimin and its translocated coreceptor (Tir) in the pathogenicity of REPEC, …

Role of adhesive factor/rabbit2 in experimental enteropathogenic Eschiria coli O103 diarrhea of weaned rabbit

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The long-term cytoskeletal rearrangement induced by rabbit enteropathogenic Escherichia coli is Esp dependent but intimin independent.

Attaching and effacing rabbit enteropathogenic Escherichia coli (REPEC) of the O103 serogroup adhere diffusely on HeLa cells and trigger a slow progressive cytopathic effect (CPE) characterized by the recruitment of vinculin and the assembly of actin stress fibres. In contrast to REPEC O103, the reference human EPEC strain E2348/69 is unable to trigger the CPE. In this study, we have shown first that the fimbrial adhesin AF/R2, which mediates the diffuse adhesion of REPEC O103, was not sufficient to induce the CPE capability upon E2348/69. Non-polar mutants of REPEC O103 for espA, espB, espD and eae were then constructed. The four mutants were unable to induce attaching and effacing lesions…

Type III Secretion-Dependent Cell Cycle Block Caused in HeLa Cells by Enteropathogenic Escherichia coliO103

ABSTRACT Rabbit enteropathogenic Escherichia coli (EPEC) O103 induces in HeLa cells an irreversible cytopathic effect characterized by the recruitment of focal adhesions, formation of stress fibers, and inhibition of cell proliferation. We have characterized the modalities of the proliferation arrest and investigated its underlying mechanisms. We found that HeLa cells that were exposed to the rabbit EPEC O103 strain E22 progressively accumulated at 4C DNA content and did not enter mitosis. A significant proportion of the cells were able to reinitiate DNA synthesis without division, leading to 8C DNA content. This cell cycle inhibition by E22 was abrogated in mutants lacking EspA, -B, and -D…

Adhesion and cytopathic effect mutants: towards new oral vaccines against rabbit O103 colibacillosis

Regulation of expression of the adhesin AF/R2 of Escherichia coli O103 by bacto-peptoneTM. Preliminary results

Enteropathogenic Escherichia coli O103 from rabbit elicits actin stress fibers and focal adhesions in HeLa epithelial cells, cytopathic effects that are linked to an analog of the locus of enterocyte effacement

Escherichia coli O103, a major agent of weaned-rabbit diarrhea in Western Europe, was previously shown to produce diarrhea and attaching-and-effacing intestinal lesions in experimentally infected rabbits and to possess a homolog of the eaeA gene of enteropathogenic E. coli (EPEC). In the present study, we have shown that although negative in the fluorescent-actin staining test on HeLa cells, prototype rabbit E. coli O103 strain B10 was able to induce an original cytopathic effect (CPE) in the same interaction model. This CPE was characterized by a generalized reorganization of the actin cytoskeleton and the formation of focal adhesions on the entire surface of the target cells. These effect…

Vaccination orale contre les infections par les REPEC grâce à une souche bactérienne vivante atténuée double mutante

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