E.Coli O157 (Fecal) ELISA kit description:

[E Coli ELISA kit]
The Diagnostic Automation Inc. (E.Coli ELISA kit) E. coli O157 Antigen Detection ELISA is an in vitro procedure for the qualitative determination of Escherichia coli O157 antigen in feces. E. Coli O157 ELISA kit is designed as a screening tool to allow rapid presumptive determination of the presence of E. coli O157 bacteria without prior culturing of the stool specimen. All positive samples in the ELISA should then be cultured and serotyped to confirm the presence of O157 and its H antigen type.

E. coli O157, predominately O157:H7, has been implicated as the causative organism of hemolytic uremic syndrome (HUS) and hemorrhagic colitis (HC). HUS syndrome is characterized by microangiopathic hemolytic anemia, thrombocytopenia and renal failure while HC typically presents with abdominal cramps and watery diarrhea followed by a hemorrhagic discharge resembling lower gastrointestinal bleeding. Typically diagnosis has been done by culturing on sorbitol-MacConkey medium and then using typing antiserum. However, current latex assays and some typing antiserum have shown cross reactions with non-E. coli O157 colonies. Furthermore, not all E. coli O157 strains associated with HUS are nonsorbitol fermentors. Both syndromes have been associated with E. coli O157 and O157:H7 but are not limited to these organisms. These syndromes appear to be more closely linked to any organism that produces Shiga-like toxins. The E. coli O157 outbreaks are believed to be passed by the fecal oral route and has been isolated in an increasing number of food related poisonings involving undercooked beef and dairy products.

The Council of State and Territorial Epidemiologists recommend that clinical laboratories screen at least all bloody stools for this pathogen.17 The American Gastroenterological Association Foundation (AGAF) recommended in July 1994 that all stool specimens should be routinely tested for E. coli O157:H7.15 It is recommended that the clinician check with their state health department or the Centers for Disease Control and Prevention to determine which specimens should be tested and whether the results are reportable.

This assay is a double antibody (sandwich) ELISA using an anti-E.coli O157 antibody to capture the antigen from the stool supernatant. A second antibody, conjugated to peroxidase (HRP), is then added which binds to the complex. This reaction is visualized by the addition of the chromogen tetramethylbenzidine (TMB). The resulting blue color development indicates the presence of E. coli O157 antigens being bound by the anti-E. coli O157 antibodies.