الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
We can report that S. Enteritidis and S. Typhimurium are common serotypes in commercial layer farms in Dakahlia province. Because they have an economic and a public health importance, a wide and a long term survey covering all the country is strongly required and a strategic plan for the elimination of S. Enteritidis and S. Typhimurium is very necessary. In this study we isolated and identified multidrug-resistant strain of S. Typhimurium from layer farms. Slide agglutination test and multiplex PCR were used for Salmonella serotyping. Furthermore, we characterized many important antimicrobial resistance genes by using PCR and DNA sequencing. These resistance genes confer resistance to many antimicrobial agents regularly used in poultry farming. It is clear that both inactivated Salmonella vaccines, have a good protection against the colonization of the challenge Salmonella strain in the internal organs of birds especially ovary, the fecal shedding and the egg deposition and subsequently reduction in the incidence of egg and meat contamination with Salmonella resulting in a reduction of the human health hazard. It is also clear that two doses of vaccination are better than one dose of vaccine. We can also conclude that the vaccination is recommended for all commercial laying flocks to reduce both fecal shedding and egg contamination of S. Enteritidis and to eliminate S. Enteritidis from large multi-stage laying farms that was unlikely to be possible, without vaccination beside good cleaning and disinfection.