الفهرس 
Cover Page Title in EnglishOnly 14 pages are availabe for public view
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Abstract
Bovine salmonellosis is a worldwide bacterial disease causing great animal losses, public health and economical problems This study was conducted on 160 animals (130 calves) and (30adult cattle). the animals were raised at Alexandria governorate, individually or in farms. A total number of 85 calves were suffering from diarrhea and 45 were apparently healthy and 15 adult cattle were suffering from diarrhea and 15 were apparently healthy. The clinical features of diarrhea in most of the cases the diarrhea ranged from yellowish watery to greenish watery diarrhea, and blackish watery, some cases present blood clots and/or mucus with diarrhea, some animals showed elevated body temperature The seasonal incidence of diarrhea with salmonellosis mainly occur in the season of winter and in the season of autumn All samples collected were subjected to bacteriological examination for isolation and identification of Salmonella species The results revealed the isolation of Salmonella from 11 (13%) and 1 (6.6%) diarrheic calves and one adult cattle respectively. On contrary, no Salmonella could be isolated from both apparently healthy calves and adult cattle Serotyping of 12 isolated Salmonellae (11 from calves and 1 from adult cattle), revealed 8 serotypes: Salmonella Enteritidis (2), Salmonella Hadar (2), Salmonella Typhimurium (2), Salmonella Kentuky (2), Salmonella Infantis (1), Salmonella Tsevie (1), Salmonella Magherafelt (1). All the pervious serotypes were isolated from calves, Salmonella Virchow(1) was isolated from one adult cattle In the present work 10 isolates were examined by PCR for the presence of three virulence gene: Salmonella invasion gene (invA), Salmonella enterotoxin gene (stn) and plasmid encoded fimbriae gene (pefA) ). The invA gene was detected in 7 (70%) isolates while stn gene was detected only in 2 (20%) isolates, but pefA gene could not be detected in all 10 Salmonella isolates The 12 Salmonella isolates were examined for antimicrobial sensitivity using 10 antibiotic discs. 12 (100%) isolates showed resistance to at least one antimicrobial, the highest sensitivity was observed for streptomycin, gentamycin and neomycin, while the highest resistance was observed for erythromycin 12 (100%), tetracycline 8 (67%) and ampicillin 7 (58%), Salmonella Hadar was the most resistant Salmonella species where it was resistant to 9 of 10 antimicrobial used in this study while Salmonella Tsevie and Salmonella Typhimurium were the most susceptible species to antibiotics as it was susceptible to 9 of the 10 antimicrobials used.