جداسازي ، سنجش و روتوكسين و گروه بندي سرمي سويه هاي اشريشيا كلي انتروهموراژيك در فصل پاييز 1378 در استان ايلام

ISOLATION , VEROTOXIN ASSAY AND SEROGROUPING OF ENTEROHEMORRHAGIC E. COLI (EHEC) STRAINS IN ILAM PROVINCE (AUTUMN, 1999)

Verotoxin producing E.coli belonging to several different "0" serotype, have been associated closely with Hemolytic Uremic Syndrome (HUS) and Hemorrhagic Colitis (HC). In order to isolate EHEC and carry out verotoxin assays of EHEC strains in Ilam Province 1557 faecal samples were collected. stool samples were cultured for initial isolation of EHEC on sorbitol Macconkey agar medium and biochemical tests were used for confirmation of EHEC. The colony sweepy polymyxin-B extraction method was used for extraction of toxin.In this study, 26 isolates of EHEC were isolated and all of them produced a cytopathic effect on Vero cells. No significant difference was seen between the rate of separated EHEC and diarrhea was observed in rural areas and most of the cases who were EHEC positive were normal and had no diarrhea , but this difference was significant in urban areas. (P=0.001). Neutralization assay revealed that the cytopathic effect on vero cells induced by 18 samples(69.2%) could be neutralized with anti-VT] serum, and 7 (26.9%) with anti-VT2. The effect of I sample (3.9%) could only be neutralized with a mixture of anti-VT] / VT2 sera. In serogrouping test among the 26 isolates,one isolate(3.9%) showed an agglutination reaction with antiserum 0157:H7. The findings indicate that in Ilam , EHEC isolates are present and VT1 are produced by most of the strains.