Prevalence of Escherichia Coli in Some Selected Foods and Children Stools with Special Reference to Molecular Characterization of Enterohemorrhagic Strain

Abstract

Escherichia coli is one of the most important etiologic agents of childhood diarrhea that represents a major public health problem in developing countries and now is being recognized as emerging entero-pathogens in the well developed countries. Among the diarrhegenic Escherichia Coli (DEC) this work was focused on the Enterohemorrhagic Escherichia Coli (EHEC) that produce Shigatoxins (Stxs). The infection is mainly transmitted through food of bovine origin such as beef and dairy products that has been often associated with outbreaks which ranged from mild diarrhea to the life-threatening hemolytic uremic syndrome. The aim of this study was to evaluate the incidence of potentially virulent STEC isolates from minced meat, some selected dairy products and from children clinical cases. Out of 360 samples, a total of 115 E.coli isolates were recovered as following 35 (30.43%) isolate from meat, 21 (18.26%) from raw milk, 31 (26.96%) from cheese and 28 (24.35%) from children stool. The identification were based on Microscopical examination, Biochemical identification and Serotyping. Twenty eight isolates were identified serologically. O26:K60 serotype 6 (21.4%) was found to be the most prevalent serotype. Screening for virulence genes (Stx₁, Stx₂, eaeA, hlyA) was done using multiplex PCR, which revealed detection of the target genes in 10 out of 115 (8.7%) examined samples. About 7 (70%) samples possessed eaeA gene alone; while 2 (20%) samples contained Stx₂ gene. Both Stx₁ and eaeA genes were detected in 1(10%) sample only.