Detection of Virulence Genes of Salmonella in Diarrhoeic Ducks by using Polymerase Chain Reaction (PCR)

SٍٍALMONELLA spp. is responsible for various food borne outbreaks. Incidence of Salmonella among the examined diarrheic ducks was 5.5%. The occurrence was 6.15% in young ducks which was higher than that in adult duck 4.28%. The total incidence of Salmonella in slaughtered ducks was 3.33%. The serovars were S.Infants, S. Typhimurium , S. Virchow from fecal samples of adult ducks and S. Agona, S. Infants, 2 S. Kentucky, 2 S. Longhorn, S. Typhimurium and S. Virchow in fecal samples of young ducks while from slaughtered ducks were (S. Kentucky and S. Typhimurium from both caeci and intestines and S. Typhimurium from livers ). Variation in pathogenicity and enterotoxin production of Salmonella isolates were observed. Sensitivity of salmonellae to ciprofloxacin, flumequine were 56.3%, enrofloxacin , gentamicin and norfloxacin were 50% and trimethoprim was 18.8%. All isolates were resistant to doxycycline hydrochloride and penicillin. All isolates from diarrheic and slaughtered ducks harbor invA gene and amplified at 284bp. Sixteen Salmonella isolates examined for pef gene at 700bp that was present in 2 S. Typhimurium, S. Agona and S. Kentucky isolated from diarrheic ducks and 2 S. Kentucky isolated from slaughtered ducks. Finally we investigate the presence of stn gene that was encoded on plasmid DNA and amplified a region 617bp in 16 isolates of Salmonella 2 S. Typhimurium, 2 S. Virchow, S. Agona, S. Infant, 2 S. Kentucky and S. Longhorn isolated from diarrheic ducks while 2 S. Kentucky isolated from slaughtered ducks harbored this gene.