الفهرس 
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Abstract
Diarrhea is a major problem of livestock in Egypt and throughout the world. Salmonella is one of the main etiological agents of infectious diarrhea and represents a zoonotic hazard worldwide. In the current study, a total number of 197 and 149 diarrheic sheep and goats of different age groups, at different seasons were clinically examined and from which rectal swabs were collected. Rectal swabs were bacteriologically examined for isolation of Salmonella. There were 5 Salmonella isolates recovered from diarrheic goats (3.36%) and 3 from diarrheic sheep (1.52%). The highest rate of Salmonella infection among the examined diarrheic sheep and goats was in Spring season and in (1-2.5 years) age group. Serological identification of the recovered Salmonella isolates revealed 6 different serotypes (Salmonella Bonariensis, Salmonella Kottbus, Salmonella Stanleyville, Salmonella Enteritidis, Salmonella Paratyphi A and Salmonella Ferruch) and 2 Untypable isolates. The recovered isolates were examined for their antimicrobial sensitivity and it was found that the highest resistance rates were recorded against ampicillin, amoxicillin, levofloxacin and ciprofloxacin with resistance rates 100%, 62.5%, 62.5% and 50%, respectively. While the highest sensitivity rates were detected for cefotaxime, gentamycin, amikacin, streptomycin, norfloxacin, sulphamethaxozle+trimethoprim, chloramphenicol and enrofloxacin with sensitivity rates 87.5%, 87.5%, 75%, 75%, 62.5%, 62.5% ,62.5% and 50%, respectively. PCR was applied for genotypic characterization of virulence genes (invA, Stn, bcfc and avrA). All isolates were positive for the 4 virulence genes. Also, PCR was used for confirmation of the existed resistance pattern in antibiogram test. All isolates (8) which are resistant to ampicillin (β-Lactam antibiotic) have blaTEM resistance gene, 3 isolates which are resistant to sulphamethaxozle+trimethoprim (Potentiated sulphonamides) have sul1 and dfrA resistance genes, 5 isolates which are resistant to levofloxacin, 3 which are resistant to enrofloxacin and 2 isolates which are resistant to norfloxacin (Flourquinolone group) both have qnrs gene and 3 isolates which are resistant to doxycycline (Tetracycline group) have tetA(A) resistance gene. The presence of the virulence and antimicrobial resistance genes within the Salmonella strains exhibiting specific MDR may make the strains clinically more relevant.