Enteroinvasive E. coli (EIEC)
E. coli strains that are enteroinvasive (EIEC) are uncommon in both industrialized and developing nations. A period of watery diarrhea that occurs before the development of sparse dysenteric stools including blood and mucus is a characteristic of EIEC infections.
Pathogenic strains are mostly linked to a small number of limited O serotypes, specifically O124, O143, and O164. Shigella spp. and EIEC strains have close biochemical, genetic, and pathogenetic ties.
Disease Origin
It results in dysentery and intestinal ulceration (diarrhea with mucus and blood, called bacillary dysentery resembling Shigellosis).
Transmission Mode
Although person-to-person transmission does happen occasionally, EIEC outbreaks are typically water- or food-borne. Since EIEC has a larger infective dosage in volunteers than Shigella spp. does, the risk of person-to-person transmission is reduced.
E. coli enteroinvasive’s pathogenesis (EIEC)
The pathophysiology of EIEC includes
- Epithelial cell penetration
- Endocytic vacuole destruction
- Intracellular growth
- Cytoplasmic migration in a specific direction
- Extension into nearby epithelial cells
EIEC is invasive rather than toxic
A sequence of genes on a plasmid mediates bacterial invasion (pInv genes) into the colonic epithelium. The epithelial cell invasion is most crucially mediated by a plasmid-coded antigen called virulence marker antigen (VMA) (VMA).
- Following that, the bacteria lyse the phagocytic vacuole and begin to grow inside the cell.
- Actin tail development controls movement throughout the cytoplasm and into nearby epithelial cells (similar to that observed with Listeria).
- Colonic ulceration can result from this process of epithelial cell death and inflammatory infiltration.
Clinical traits
The bacteria can enter the colon and kill the epithelium, resulting in a condition that starts off with watery diarrhea. Only a small percentage of patients go on to develop the dysenteric form of the illness, which is characterized by fever, chills, malaise, cramps in the abdomen, and blood and leukocytes in stool samples.
Diagnosis
It can be challenging to diagnose EIEC strains apart from Shigella spp. and other E. coli strains, including non-pathogenic types. In general, proving that an organism is an EIEC requires showing that it has the biochemical profile of E. coli while also having the genotypic or phenotypic traits of Shigella spp.
HeLa cell invasion assay with ELISA for the detection of VMA
Serenity check (inoculation of bacterial suspension into guinea pig eyes produces conjunctivitis)
EIEC are biochemically unusual E. coli strains as compared to other E. coli strains because they are non-motile, lactose non-fermenters, and negative for lysine decarboxylase.
