Enterohemorrhagic Escherichia coil (EHEC) is one of diarrheagenic E. coli that
produce Shiga toxins (Six) causing diarrhea, Hemorrhagic Colitis (HQ, and
Hemolytic Uremic Syndrome (HUS). E. coli 0157:H7 is the most common and the
one that can be identified in the clinical specimens of the EHEC species. Shigella
dysenteriae type 1 (Shigella shiga) produces shiga toxin, identical to Six-I, thus
causes HC and HUS. The aim of this work was to detect the role of Shigella shiga
and E. colt 0157 as causative agents of hemorrhagic diarrhea, and detecting
cytopathic effect of verotoxin producing E. coli 0157 on tissue culture. 70 stool
samples collected from patients with bloody diarrhea were investigated for the
presence of E. coli 0157 and Shigella shiga by culture methods on Sorbitol
MacConkey agar and ChromJDTM 0157:117) and latex agglutination test. Cytotoxic
effect to Vero cells of isolated E. colt 0157 was also determined. This study found
that (10%) of isolated organisms was E.coli 0157, Shigella shiga also represent the
same percent, while E.coli 0111 and E.coli 026 represent (8.6%, 5.6%) respectively.
About 85.7 % of isolated E.coli 0157 showed a reasonable toxicity to Vero cells post
treatment with bacterial toxin by tetrazolium-based colorimetric assay (MTT assay).
E. coli 0157 and Shigella shiga play major role in the etiology of hemorrhagic
diarrhea. In addition, stool culture on Sorb itol MacConkey agar followed by
Chro,nJDTM 0157:H7 agar is a simple and reliable method for E. coli 0157
detection. |
