Studies on Shiga-toxins [STX1 and STX2] produced by escherichia coli isolated from diarrheal cases in Assiut university children hospital

ABSTRACT

Shiga toxin producing E. coli. [STEC] are emerging pathogens capable of producing sporadic and epidemic diarrhea that may be complicated by haemorrhagic colitis and life threatening hemolytic uremic syndrome [HUS]. The goals of the present study is testing stool specimens for Shiga toxins [Stx1 and Stx2] and detection of the prevalence of the Shiga toxin producing E. coli [STEC] among the diarrheal cases collected in Assiut University Children Hospital. For these purposes, stool specimens from 150 inpatients and 150 outpatients with diarrhea, watery diarrhea or bloody diarrhea and from 40 infants and children with no gastrointestinal illness as control were collected from Assiut University Children Hospital. Escherichia coli was detected in 30 [20%], 64 [42.67%] and 12 [30%] of the inpatients, outpatients and control group respectively. The detection of the Shiga toxins [verotoxins] was done by phenotypic method [Vero cell cytotoxicity assay], immunological method [EIA using RIDA screen kit] and finally by genotypic method [multiplex PCR]. During our study, multiplex PCR [as gold standerd] showed that 4 [13.33%] and 17[26.56%] of E. coli isolated from the inpatients and outpatients respectively were STEC. Non of the E. coli isolateded from control group were STEC. Seven [33.3%] of STEC isolates carried Shiga toxin 1 [Stx1] genes and 14 [66.7%] of STEC isolates carried Shiga toxin 2 [Stx2] genes