E. coli fimbriae<unk>  is transmitted through the fecal-oral route and primarily contaminated by food and water.<unk>  has been associated with many symptoms such as diarrhea in some individuals and intestinal colonization in others. Because many strains of<unk>  have been identified, it is difficult to identify the mechanism of its pathogenesis. Most candidate virulence genes are not always connected with disease. The model of<unk>  pathogenesis comprises three stages: Stage 1 is the attachment of the intestinal mucosa by aggregative adherence fimbriae (AAF) and other adhering projections, Stage 2 an increase in mucus that covers<unk>  on its surface of enterocytes is found; Stage 3 evocation of an inflammatory response, mucosal toxicity, and intestinal secretion as well as a release of toxins exist. Stage One: Aggregative adherence factors (AAF) are responsible for the adhesion to the intestinal mucosa. AAF are made up of three fimbriae encoded by the pAA plasmid; aag aafA agg-3. aggA is in charge of aggregative phenotype and human erythrocyte haemagglutination of<unk> . aafA allows<unk>  to adhere to the intestinal mucosa. agg-3 serves as an adhesion. MAP, three-membrane associated proteins, are essential in the<unk>  adherence to haemagglutination of animal cells. Stage two: After AAF factors in stage 1, adherence to the mucosa is characterized by the presence a biofilm. The production of biofilm is regulated by AggR and demands several genes. The loss of biofilm production and diffuse adherence pattern was reported in<unk>  at a pH of 4.0. Many studies reveal that<unk>  are capable of surviving in the mucus layer. This evidence can support why malnourished children who are infected with<unk>  and live in poor conditions develop mucoid stools and prolonged diarrhea. Stage Three: Cytotoxic effects are found in the release of toxins in<unk>  as well as an elicitation of the inflammatory response, mucosal toxicity, and intestinal secretion.<unk>  toxins are destructive to the intestinal villi and enterocytes. There are three toxins found in<unk> ; plasmid encoded toxin (Pet), heat-stable toxin (EAST1), and Shigella enterotoxin 1 (ShET1).
Enteroaggregative Escherichia coli
Enterotoxigenic Escherichia coli
Enteroinvasive Escherichia coli
Salmonella
Escherichia coli O157:H7
Clostridioides difficile 
Campylobacter upsaliensis
Yersinia enterocolitica