Salmonella is considered as one of the major economic problems facing poultry industry all over the world because of its significant losses.
Aim: The present study was aimed to identify Salmonella species isolated from poultry feed, water and litter. determination of their antibiotic’s sensitivity. Detection of some virulence and resistance genes.
Materials and Methods: A total of 100 samples of feed (40), water (36) and litter (24) were collected randomly from different chicken shops, houses, and farms in Kafr El-Sheikh Governorate. Isolation and identification of Salmonella were done on selective media and by biochemical and serological tests. The Sensitivity test was made against 12 antibiotics (cefotaxime 30 μg, doxycycline 20 μg, cephradine 20 U, Erythromycin 20 μg, amikacin 30 μg, flumequine 30 μg, ceftazidime 30 μg, lincomycin 25 μg, Clindamycin 25 μg spectinomycin 20μg, Ciprofloxacin5 μg and Neomycin 30 μg. Multiplex PCR was used for detection of resistance genes (blaTEM, qnrS) and virulence genes (Stn, invA) of Salmonella.
Results: out of 100 samples, 14 Salmonella species (14%) were isolated; three isolates from litter (12.5%), five isolates from water (13.89%) and six isolates from feed (15%). In total four different Salmonella serotypes were identified: S. Kentucky (33.33%), S. Blegdam (33.33%), S. Yovokome (11.11%) and S. Ferruch (22.22%). The most isolated Salmonella spp. (88.89%) were found to be resistant to ciprofloxacin (fluoroquinolones) and cefotaxime (cephalosporin) with 89%, while they were highly sensitive to amikacin with (100%). Stn and invA virulence genes plus blaTEM and qnrS resistance genes were detected in the four Salmonella serotypes.
Conclusion: Amikacin could be considered the first drug of choice for treatment of Salmonella infection. Detection of invA and stn (virulence genes) in the identified Salmonella serotypes, suggested them as a gene marker for the rapid detection of the virulent strains of Salmonella. blaTEM and qnrS resistance genes explain their resistance to ciprofloxacin (fluoroquinolones) and cefotaxime.
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