MOLECULAR CHARACTERIZATION OF GENES LINKED TO ANTIMICROBIALS AND VIRULENCE RESISTANCE IN SALMONELLA SP. ISOLATED FROM BROILER CHICKENS

Document Type : Research article

Authors

1 Department of Avian and Rabbit Medicine, Faculty of Veterinary Medicine, Assiut University, Assiut, Egypt.

2 Poultry Diseases department, Animal Health Research Institute, Agricultural Research Center (ARC), Assiut, Egypt.

Abstract

Fifteen Salmonella strains representing four Salmonella serovars (S.Anatum, S.Montevideo, S.Typhimurium and S.Boecker) were isolated, purified, and identified from freshly dead and diseased chickens suspected to be infected with Salmonellosis. In this study, antimicrobial resistance to 14 different antimicrobials and virulence genotyping to those Salmonella strains were performed. All isolates were completely sensitive (100%) to amikacin, Sulphamethoxazole/trimethoprim, Flumequine, Neomycin and gentamicin. Isolates responded variably to tetracycline, colistin sulfate and cephradine. Intermediate sensitivity to streptomycin and for doxycycline and Ciprofloxacin was observed.
In contrast, all isolates were completely resistant to Ampicillin, Cefotaxime and Amoxicillin. The genotypic resistance of studied serotypes against the Sulfonamide resistance gene. β-lactams resistance gene, Streptomycin resistance and Tetracycline resistance gene showed that all Salmonella studied serotypes (100%) have Sul-1gene, and were also positive for bla TEM gene, (aadA) and (TetA A) gene at PCR respectively. while two Salmonella serotypes (50%) were positive for (qnrA) gene blamable for Quinolones resistance. The efficacy of four disinfectants was evaluated; Quaternary Ammonium Compound, Iodine compound, Organic ‎salt and Acid and H2O2 used by commercial poultry disinfectants. All the investigated 4 Salmonella serotypes showed no observable growth after treatment, with 3% hydrogen peroxide and 2% organic salt and acid and 3% QAC and visible growth at 1% and 2% hydrogen peroxide and iodine at the recommended user-dilution. Results of screening of some MDR isolates by multiplex PCR for detection of some virulence genes showed that all the tested isolates (100%) had hilA, sopB, stn, and invA.

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Assiut Veterinary Medical Journal
Volume 70, Issue 183
October 2024
Pages 166-184

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