Escherichia coli: identification of several pathotypes of Escherichia coli by detecting the genes encoding toxins or other mechanisms of pathogenicity by PCR.
Several virulent types (virotipos) Escherichia coli, each producer pathology through a different mechanism.
- Enterotoxigenic Escherichia coli (ETEC), which causes pathology electrolyte imbalances of cells of the intestinal mucosa due to the production of heat labile toxin (LT), and / or heat - stable toxin (ST), encoded respectively by genetic locus lt and st. These toxins, increase the content of the mucosal cell cyclic-AMP, GMP-cyclic or by induction of adenylate cyclase or guanylate cyclase enzymes respectively. In effect, they do not alter the morphology of mucosal cells or cause inflammation in the mucosa, causing diarrhea and vomiting, with or without fever.
- Enteropathogenic Escherichia coli (EPEC): this virotipo causes damage to cells of the mucosa, with an elongation of microvilli inducing cells reorganization of actin fibers. The effect is accompanied by an inflammatory response. Those affected have prolonged diarrhea and fever nonbloody. These strains have the genetic locus bfpA.
- Enteroaggregative Escherichia coli (EAggEC, EAEC): this virotipo groups adheres to mucosal cells without invade, and without causing morphological change, but alters functionally performs like toxin ST (thermoset). These strains have the genetic locus aggR and aggA.
- Enteroinvasive Escherichia coli (EIEC): this virotito invades cells of the colonic mucosa, ranging from one cell to another, similar to as Shigella spp causes damage without toxin production.. It manifests as watery diarrhea or bloody diarrhea. These strains have the genetic locus ial.
- Enterohaemorrhagic Escherichia coli, verotoxin producing, or shiga toxin (EHEC, VTEC, STEC): this virotito binds to mucosal cells without invade, but produces shiga (of Shigella dysenteriae). The process manifests as mild diarrhea or bloody diarrhea, and in severe cases as a hemolytic-uremic syndrome with hemolytic anemia, thrombocytopenia and renal failure. They have mainly involved serotypes O157: H7, O157: NM, but today other serotypes O157 involved are not known. It is mainly acquired from meat products, dairy products, vegetables contaminated products, and there is even the possibility of human transmission. Causing strains are producers of sxt1 and / or sxt2 toxins, or other types sxt, encoded by the corresponding genetic locus sxt1 and/or sxt2.
Tests in IVAMI
Enterotoxigenic Escherichia coli (ETEC)
- Gene detection thermolabile enterotoxins (LT) (lt locus) and / or
- Gene detection thermostable enterotoxin (ST) (locus st).
Enteropathogenic Escherichia coli (EPEC)
- Detection of gene bfpA locus.
- Detection of gene aggR and aggA locus.
- Detection of gene ial locus.
Escherichia coli enterohemorágico with verotoxin or shiga toxin (EHEC = VTEC = STEC)
- Detection of toxin genes sxt1 and / or sxt2, or other types (rfbE, wbdl, wzx, ihp1, wzx, fli).