Escherichia coli enterohemorrágica aislada de terneros con diarrea sanguinolenta produce efecto citotóxico en colon humano

PISTONE CREYDT VIRGINIA; VENZANO AGUSTÍN; VILTE DANIEL; MERCADO ELSA; IBARRA CRISTINA

Buenos Aires, Argentina

Congreso; XVII Congreso Latinoamericano de Microbiología y X Congreso Argentino de Microbiología; 2004

Asociación Latinoamericana de Microbiología

@font-face { font-family: "Arial"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; } Enterohemorrhagic Escherichia coli (EHEC) is one of the most important emergent food pathogens causing diarrhea, hemorrhagic colitis and hemolytic uremic syndrome in children. Although cattle are considered the principal source of human infections, the effects of EHEC strains from bovine origin in human colon have not been explored. In this work, we examined the physiological and morphological effects of strains 97/23-A (O26:H11; stx2; eae-b; ehxA) and 01/289-1 (O111:H-; stx1; eae-q; ehxA), isolated from calf feces with bloody diarrhea, on human colonic mucosa by the Ussing chamber technique. We found that the absorptive net water flux (Jw) decreased while the short-circuit current (Isc) increased after the addition of bacterial culture. Tissues showed erosion of the mucosa with epithelial exfoliation and presence of pseudomembranes in the lumen. Colonic crypts were not disrupted. Treatment of the mucosa with bacterial supernatant decreased Jw whereas Isc remained unchanged. These effects were neutralized by preincubation with a monoclonal antibody anti-Stx2B. The addition of washed bacteria produced an increase in Isc similar to that observed with whole cultures, indicating that this alteration was mainly due to bacterial cells. This is the first study showing physiological and morphological alterations in human colon caused by EHEC strains isolated from cattle with diarrhea.