الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
Enterotoxigenic E. coli (ETEC) strains, are a major cause of infant dialThea in less-developed countries, one of the main bacterial causes of dehydrating infant diaIThea in developing areas and an infection correlated with adverse nutritional consequences. They are rarely responsible for diaIThea in temperate countries with good hygiene, but cause about half of the episodes of diaIThea in travellers from these countries to the tropical and - developing countries. ETEC colonize the proximal small intestine, where they elaborate heat-labile enterotoxins (L TI and L Tu) , or heat-stable enterotoxins (ST a and ST b) , or both that cause the sma11 intestine to secrete water and electrolytes leading to watery diaIThea . This bacterial colonization is achieved by means of fimbriae-hair like organe1les found on the surface of the organism called colonization factor antigens (CF As) , that a110w them to overcome the peristahic defense mechanism of small intestine and the adherence to the enterocytes . As there is no reliable and easy biochemical or other markers to distinguish ETEC from non ETEC strains, their recognition depends upon the demonstration of enterotoxin production. Several biological methods have been used for the detection of ETEC such as the classical laboratory measures as rabbit ligated ileal loop , skin penneability factor etc , and the tissue cultures such as the mouse Y I adrenal cel1s and Chinese hamster ovary cel1s in case of LT toxins and the suckling niice assay in case of ST toxins. A wide range of immunological techniques are now available for the detection of LT including the Biken test, CIE , ELISA , RIA , CoA test and latex agglutination test. Recently ST toxins are also identified by ELISA and indirect immunodot assay. Radio-labelled and biotin-labelled gene probes have also been developed for the detection of both LT or ST enterotoxins ii1 stool, food or water samples containing ETEC . The aim of this study was to evaluate the utility of a latex agglutination tests as a rapid and specific immunological tool in the diagnosis of ETEC among infants suffering from acute watery diarrhea and compare this method with a classical biological measure (Rabbit ligated ileal loop test) . This study was carried out on 100 infant and child their ages ranging from 0-2.5 years, who have been attending the out patient clinic of EI-Shatby University Children Hospital in the period from Spring to Summer 1994 . Detailed History was taken from every patient’s parents. Duplicate rectal swabs were taken from each infant or child and transferred within 2 hours to the laboratory. Both rectal swabs were suspended in a tube containing sterile saline an~ washed thoroughly. Three loopfuls of each faecal suspension were inoculated onto a DC A agar plate and one loopful was inoculated onto a MacConkey agar plate and incubated at 37°C for 24 hours, then examined for lactose fennenting colonies with typical E. coli appearance. The suspected E. coli colonies were subjected for further biochemical identification (Indole, Motility etc) . The identified E. coli colonies were transferred to Nutrient soft agar slants, incubated at 37°C for 24 hours and then held at 4°C until tested for enterotoxin production. For toxigenicity demonstration the test and positive control strains of E. coli were subcultured onto Trypticase soy agar plates and incubated at 37°C for 24 hours, then 3-5 colonies of each strain were transferred into Trypticase soy broth containing 0.60/0 yeast extracts and 45 ~g/ml of Lincomycin, incubated in a shaking water-bath at 37°C for 18-24 hours with constant shaking at 150 rpm , then 50 Ilg/ml of Gentamicin was added to each tube and incubated for another one to two hours at 37°C with shaking. Then 2 ml of each bacterial culture fluid was transfeITed into a centrifuge tube and centrifuged at 3000 rpm for 20 minutes, then the snpematant was recovered and used as the test sample in the reversed passive latex agglutination test (VET -RPLA) and as the inocula in the rabbit ligated ileal loop bioassay (RIL) . The obtained results trom the VET -RPLA test were compared with those obtained from the RIL bioassay and the results were as follows: 1 It was found that out of the 84 well characterized E. coli isolates obtained trom 100 infant and child having acute diarrhea , 6 subjects were ETEC with an incidence rate of 7.2 . 2 The highest isolation rate for ETEC in the present study was found to be in the age group 3- 12 months, which was 5 out of the 6 positive subjects (83.30/0) with no statistical significance. 3. In the present study, males (8.20/0) were affected more than females (5.7) .