Investigations on virulence genes of some bacterial infections in Nile tilapia in Kafr El-Sheikh farms

Elbaz, Naglaa; Abd Al Fatah, Mohammad; Gaafar, Alkhateib; Soliman, Magdy

doi:10.21608/djvs.2023.200798.1112

Investigations on virulence genes of some bacterial infections in Nile tilapia in Kafr El-Sheikh farms

Document Type : Original Article

Authors

¹ Department of Poultry and Fish Diseases, Faculty of Veterinary Medicine, Damanhour University, Egypt

² Department of Biochemistry, Veterinary Medicine Directorate, Kafr El-Shiekh, Egypt

³ Department of Hydrobiology, Veterinary Research Division, National Research Center, Egypt

10.21608/djvs.2023.200798.1112

Abstract

In the last decades, aquaculture is considered a new sector of science in progressed countries and a main substitution for animal protein to decrease the widening gap between demand and supply. Therefore, the main objective of this study was to investigate the virulence genes for the main bacterial infection in Kafr El-sheikh governorate, Egypt. After surveying the understudy farms from April to November 2019, 120 Nile tilapia farms were investigated for severe mortalities in Kafr El-Sheikh region of Egypt with major aquaculture production. The clinical examination of the diseased fish Nile tilapia (Orechromius niloticus) showed severe focal hemorrhage fins, extensive mucous at the surface of the body, congested gills, and severe ulcers on the body. For identification of the most predominant bacterial isolates Pseudomonas fluorescens, Aeromonas hydrophila, and Streptococcus faecalis by using multiplex PCR for various virulent genes aprX, 16S rRNA, aerA, ahhl, gelE, asa1, esp and cylA. Our results revealed that molecular characterization of A. hydrophila strains confirmed with 100%, Ps. fluorescens was 85% and S. faecalis was 75%. We concluded that our findings provide updated information for future reference and highlight the occurrence of bacterial outbreaks with a special reference to virulent genes.

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