الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The obtained results were summarized as follows:
1- Examination of 678 organ samples collected from recently dead broilers revealed that E. coli isolates was recovered from 509 samples with overall prevalence 75.07%.
2- Out of 95 fresh heart blood samples, 72 samples were E. coli positive with an incidence of 75.79%.
3- Out of 95 examined kidney samples, 65 were E. coli positive with
a prevalence of 68.42%.
4- Examination of small intestine of recently dead bird samples, 77 out of 95 samples were positive for E. coli with a prevalence of 81.05%.
5- Isolation of E. coli isolates from bone marrow samples revealed the detection of E. coli isolates in 82 out of 95 samples with a prevalence of 86.32%.
6- The occurrence of E. coli isolates in feed samples collected from broiler farms during the study period revealed that E. coli isolates were recovered from 72 out of 80 feed samples with a percentage of 90%.
7- The prevalence of E. coli isolates in drinking water samples collected during the period of investigation showed that 22 out of 80 water samples were positive for E. coli with a prevalence of 27.5%.
8- Also, examination the occurrence of E. coli isolates in litter samples collected from investigated broiler farms indicated that 64 out of 80 litter samples were positive for E. coli with a prevalence of 80%.
9- The morphological tests used for identification of E. coli clarified that E. coli isolates are G-ve rods appeared as pink colonies when cultured on MacConkey media, green metallic colonies on EMB medium. However, appeared as red colonies on Congo red medium.
10- The biochemical tests using the API20E system for identification of suspected isolated E. coli strains revealed that 98% of suspected isolates were biochemically identical to typical E. coli features.
11- The serological tests used for identification of randomly selected E. coli (20) isolates clarified that, one E. coli isolate was serotype O1, one was O78, one was O128, two were serotype O2, two were O124, two were O125, two were O114, three were serotype O26, and six isolates could not be typed by the available Antisera (Untypable).
12- Prevalence of E. coli isolates in broiler poultry farms from different samples revealed that E. coli isolates was isolated in 667 (72.65%) out of 918 poultry farms samples originated from different sources including; feed (72 out of 80 “90%”), water (22 out of 80 “27.5%”), litter (64 out of 80 “80%”), fresh heart blood (72 out of 95 “75.79%”), liver (88 out of 95 “92.63%”), lung (47 out of 95 “49.47%”), kidney (65 out of 95 “68.42%”), brain (68 out of 95 “71.58%”), small intestine (77 out of 95 “81.05%”), air sac (10 out of 13 “86.93%”), and bone marrow (82 out of 95 “86.32%”).