Secreted autotransporter toxin produced by a diffusely adheringEscherichia colistrain causes intestinal damage in animal model assays

Abstract

Bacterial diarrheal diseases remain a major cause of morbidity and mortality in developing countries. Diffusely adhering Escherichia coli (DAEC) is a newly proposed category of diarrheagenic E. coli based on epidemiological studies. Sat, a new virulence factor of some uropathogeic Escherichia coli, was described with a vacuolating cytotoxic action in bladder and kidney tissues. In the present study, we analyzed the Sat effects, produced by a DAEC strain in rabbit ileal intestinal tissue and cultured epithelial cells. We observed enterotoxic activity in rabbit ileum tissues by Ussing chamber assays, a pronounced fluid accumulation in rabbit ileum loops with villous necrosis observed in the histopathologic examination, and morphological changes in monolayer cultures of Y1 adrenal cells. Our results suggest that DAEC strains may be involved in diarrhea.

Genetic Virulence Profile of Enteroaggregative Escherichia coli Strains Isolated from Danish Children with Either Acute or Persistent Diarrhea

“…Biofilm formation is a key pathogenic trait for the development of persistent infection (Costerton et al, 1999) and the formation of biofilm is what separates EAEC from other diarrheagenic E. coli pathotypes. The sat gene has been shown to cause intestinal damage with fluid accumulation and villus necrosis in a rabbit ileal loop model (Taddei et al, 2005). Sat was one of the most prevalent genes detected in children with diarrhea in an Iranian study (Nezarieh et al, 2015).…”

“…Biofilm formation has been associated with the genes aatA, aggR, pic, sepA , and sigA (Mohamed et al, 2007; Mendez-Arancibia et al, 2008; Nezarieh et al, 2015) and the AAFs (Czeczulin et al, 1997; Shamir et al, 2010; Jønsson et al, 2015; Nezarieh et al, 2015). The genes sat and the pet are toxins that causes considerable damage to the intestinal epithelium (Eslava et al, 1998; Taddei et al, 2005). In a Brazilian study investigating childhood diarrhea, the toxin gene astA was associated with acute diarrhea, and the CVD432 probe (corresponding to the aatA gene) was associated with persistent diarrhea (Pereira et al, 2007).…”

An Experimental Study and a Randomized, Double-Blind, Placebo-Controlled Clinical Trial to Evaluate the Antisecretory Activity ofLactobacillus acidophilusStrain LB Against Nonrotavirus Diarrhea

“…33,34 We conducted experiments to identify the mechanism by which L acidophilus strain LB blocks the C1845-induced increase in fluid domes. The wild-type strain C1845 expresses a toxin, known as Sat, 48 that displays enterotoxic effects that are characterized by a pronounced accumulation of intestinal fluid 49 and an increase in the paracellular permeability of Caco-2/TC7 cells. 28 We show that both the live L acidophilus strain LB and the lyophilized, heat-killed L acidophilus LB bacteria plus their culture medium inhibit the increase in the number of fluid domes in Caco-2 cell monolayers that are infected with a recombinant strain of E coli AAEC185, that secretes Sat.…”

α-Haemolysin ofEscherichia coliin IBD: a potentiator of inflammatory activity in the colon

“…E coli virulence factors such as fimbriae, enterotoxins and serine protease autotransporters (SPATES, eg, Sat) have been implicated in intestinal disorders 14 15. By contrast, the role of E coli α-haemolysin in the gut is still unclear, despite being well characterised in other respects 16.…”