Detection of some virulence gene Stx1, Stx2, and rfb of Escherichia coli isolated from fish in Nineveh governorate, Iraq

Abstract

The aim of the current study is to detect the presence of some virulence genes of Escherichia (E.) coli in fish. A total of 46 strains of E. coli were previously isolated from 153 fish samples, including 28 and 18 isolate of E. coli from local markets and fish farms, respectively, in Nineveh Governorate from November 2021 to January 2022. The results of the study show that all isolates of E. coli possessed the uidA gene with a molecular weight of 623 bp. In addition, they show that 88.9% (16/18) isolates from farmed fish samples possessed the Stx1 gene with a molecular weight of 347 bp, while 72.2% (13/18) of them carried the Stx2 gene with a molecular weight of 589 bp. Also, the study unveils that 89.3 % (25/28) isolated from the market fish samples possessed the Stx1 gene with a molecular weight of 347 bp and 85.7% (24/28) isolates carried the Stx2 gene with a molecular weight of 589 bp. The rfb gene is not detected in this study, neither in farm fish nor in the samples from the local fish markets using the PCR technique. Likewise, it shows that E. coli isolated from fish possessed the Stx1 and Stx2 genes, which are major causative agents of food poisoning for consumers. Finally, the study gives important information about the application of health conditions on fish farms and fish markets to prevent contamination and reduce infections by foodborne pathogens that cause food poisoning for humans.