Determinación de la diversidad genética y caracterización de genes de patogenicidad en aislados de Escherichia coli en pollos de engorde (Gallus gallus domesticus), Azuay, Ecuador

Abstract

In the poultry industry there are different types of pathogenic and non-pathogenic Escherichia coli, depending on the virulence associated genes (VAG) present in the bacteria. However, there are no reports for the area on the identification of E. coli VAG in broiler chickens especially in Ecuadorian andean communities. The main objective of this study was to identify the genetic diversity and the presence of VAG in E. coli strains. In this study, E. coli VAG were characterized in the Azuay Province (Ecuador) using isolates from 30 bacteriological cultures from chickens with clinical signs of colibacillosis. The PCR technique was used to detect the uspA gene (specific from E. coli) and also the GAV of adhesins (fimC), exotoxins (cvaA) and iron uptake-transport systems (iucD; chuA; fyuA) in each bacteria isolate. Pathogenic E. coli were molecularly typed by evaluating polytrinucleotide (GTG)5 sequences. The 83.33 % of the cultures presented the uspA gene from E. coli. The frequencies of positive VAG were 48 % for the chuA gene, 20 % for the cvaA gene, 84 % for the fimC gene, 36 % for the fyuA gene and 56 % for the iucD gene. Sequence evaluation (GTG)5 revealed two main phylogenetic groups of E. coli most of which carried at least one VAG gene. These results contribute to a more precise diagnosis of colibacillosis, as well as to is control and treatment by poultry farmers.