Shiga toxin-producing Escherichia coli (STEC) is considered one of the
most important emergent zoonotic food bome pathogens. A total of two
hundred random samples were collected from children with acute
diarrhea. 53 of them had blood in stools, 47 had blood in stools and
associated with hemolytic uremic syndrome (HUS). The other hundred
had no blood in their stools. Samples were collected from the
gastroenterology unit of Assiut Children University Hospital during the
period from October 2003 to September 2004. The present study was
designed to estimate the incidence of STEC 0157:H7 infection among
diarrheal children with and without blood in stools, moreover percentage
frequency of HUS among patients with positive STEC infection was
evaluated and demographic and clinical characteristics of the STEC
patients were investigated. Furthermore antibiotic resistance patterns of
the recovered strains were studied and plasmid profile of the obtained
isolates were performed to elucidate the relation between the obtained
strains. E.coli 0157:H7 could be detected in 16.98%, 17% and 3% of
bloody diarrhea, bloody diarrhea associated with HUS and non bloody
diarrhea, respectively. Ecological distribution of the examined children
revealed that the rate of infection was higher (11.3%) in rural areas than
in urban areas (5%). E.coli 0157:H7 was recovered in children fed on
bottle milk (2.5%) and animal products (17.27%) while it was not
isolated from children with breast feeding. The majority of cases in the
present study were in the age group of 7-24 months with a rate of
(18.3%), followed by those in age group of <7months with a rate of 5%.
It has been estimated that 60% of the isolated strains were resistant to
ampicillin and 10% of them were resistant to erythromycin as well as
5% of the strains were resistant to gentamycin and tetracycline. It was
revealed that out of the isolated 20 isolates of E.coli 0157:H7, 6 (30%)
harboured some copies of plasmids ranging in size from (1.1 to 45
MDa). The obtained strains harbouring plasmids were grouped into
6 plasmid profiles with different molecular weights and this results
reveal the existence of a variety of clones which may indicate several
sources of contamination.