Ex Vivo Model of Rabbit Intestinal Epithelium Applied to the Study of Colonization by Enteroaggregative Escherichia Coli

Abstract

-Background -The diarrheal syndrome is considered a serious public health problem all over the world and is considered a major cause of morbidity and mortality in developing countries. The high incidence of enteroaggregative Escherichia coli in diarrheal syndromes classified as an emerging pathogen of gastrointestinal infections. After decades of study, your pathogenesis remains uncertain and has been investigated mainly using in vitro models of adhesion in cellular lines. Objective -The present study investigated the interaction of enteroaggregative Escherichia coli strains isolated from childhood diarrhea with rabbit ileal and colonic mucosa ex vivo, using the in vitro organ culture model. Methods -The in vitro adhesion assays using cultured tissue were performed with the strains co-incubated with intestinal fragments of ileum and colon over a period of 6 hours. Each strain was tested with three intestinal fragments for each region. The fragments were analysed by scanning electron microscopy. Results -Through scanning electron microscopy we observed that all strains adhered to rabbit ileal and colonic mucosa, with the typical aggregative adherence pattern of "stacked bricks" on the epithelium. However, the highest degree of adherence was observed on colonic mucosa. Threadlike structures were found in greater numbers in the ileum compared to the colon. Conclusion -These data showed that enteroaggregative Escherichia coli may have a high tropism for the human colon, which was ratified by the higher degree of adherence on the rabbit colonic mucosa. Finally, data indicated that in vitro organ culture of intestinal mucosa from rabbit may be used to elucidate the enteroaggregative Escherichia coli pathogenesis.

Novel Segment- and Host-Specific Patterns of Enteroaggregative Escherichia coli Adherence to Human Intestinal Enteroids

“…EAEC bacteria were associated with thick mucus layers, which is notable because human volunteers challenged with EAEC 042 produced mucoid stools, along with a duodenal localization in two of the three challenge subjects, which is consistent with the strong duodenal adherence seen in our study ( 16 ). Similar histopathology was observed in a rabbit intestinal loop model, but rabbits succumb to the infection in about half the cases, which is not common in humans ( 12 , 55 , 56 ). Infant rabbits infected with the German Stx-producing hybrid EAEC strain manifest diarrhea ( 50 ).…”

Enteroaggregative E. coli Adherence to Human Heparan Sulfate Proteoglycans Drives Segment and Host Specific Responses to Infection

“…One of the more pressing biological and medical questions for diarrhea-causing E . coli , especially EAEC, is whether the variation in disease presentation (including the range of bacterial burden [ 28 ], length of colonization, and acute duration of illness [ 6 , 29 , 30 ]) is the result of host or bacterial genetics [ 31 , 32 ], and whether the tropism of the organism amongst the four distinct segments of the intestinal tract is a driver of disease variability [ 33 – 35 ]. In fact, understanding the drivers of disease presentation is of central importance to probably all infectious diseases, and more specifically with the examination of the human microbiota and its effect on human diseases.…”

Estudo sobre a adesão de >i<Escherichia coli>/i< uropatogênica com marcadores fenotípicos e genotípicos de >i<E. coli >/i<enteroagregativa a células epiteliais.

“…O padrão AA tem como característica a formação de agregados bacterianos que se assemelham a "tijolos empilhados" e pode ser observado in vitro e ex vivo (ANDRADE; FREYMÜLLER; FAGUNDES- NETO, , 2011BRAGA et al, 2017;CANDY;PHILLIPS, 1996). Em células epiteliais em cultura, o padrão AA pode apresentar variantes com as bactérias aderidas predominantemente nas células epiteliais e/ou à superfície da lamínula, em arranjos análogos a favos de colmeia (Figura 1) (GOMES et al, 2016;HEBBELSTRUP JENSEN et al, 2014;KAPER, 1998;.…”