الفهرس 
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Abstract
Detection of virulence genes and antimicrobial resistance of Escherichia coli isolated from dead-in shell chicken embryos
Escherichia coli is considered as the second principal causative bacterium causing disease, mortalities and public health hazard in poultry.
This work was carried out to identify some virulence genes of E. coli ( pho A, iss, tsh and eae A ) causing embryonic death in chicken eggs and its antimicrobial resistance through:
1- Collection of samples from three different hatcheries in kafr el sheikh governorate A total of 80 dead in shell embryos at more than 14 days of age by using a sterile swab from un absorbed yolk sac of dead in shell chicken embryo.
2- Isolation and identification of bacterial agent by streaking on Macconkey agar and Eosin methylene blue medium then confirmed by biochemical tests.
3- Antimicrobial sensitivity testing by using 4 antibiotic discs (ampicillin, ciprofloxacin, gentamycin and tetracycline).
4- Detection of the virulence genes.
The results revealed that six out of 80 samples were positive for E. coli.
The isolation of E. coli means that it is impossible to eliminate this bacteria completely.
Based on in vitro drug sensitivity assay,Gentamycin was the antibiotic to which high number of isolates were sensitive , moderately sensitive to tetracycline and resistance to ampicillin.
PCR identification of E. coli isolates gave positive results for pho-A gene as a general marker for E. coli at 720 pb, Iss gene gave positive results at 266 pb, Tsh gene gave positive results at 620pb and Iss and Tsh were detected at a percentage of 100% eae A gene was not detected in any of the isolates.