Caracterización molecular de aislados de Escherichia coli en pollos de carne (Gallus gallus domesticus) de la provincia de Azuay, Ecuador

Abstract

Escherichia coli (E. coli) can cause significant economic loses in agricultural and animal industries. In spite of the high risks that this bacterium poses to food safety, environmental health and human health, as of today, most diagnostic methods focus only in the genotypic characterization of this bacterium’s isolates without addressing whether these isolates contain virulence factor genes (VFG). The objective of this work was to identify VFGs in isolates from commercial farms and to describe the genetic diversity of these isolates. Thirty isolates from chickens showing clinical signs of colibacillosis from commercial poultry farms in the province of Azuay (Ecuador) were used in the study. The isolates were purified and confirmed using gram-staining and PCR-amplification of the E. coli-specific genetic marker uspA. VFGs presence in the isolates DNA were screened using selected markers as follows: adhesins (fimC), exotoxins (cvaA), and iron uptake and transport systems (iucD, chuA and fyuA). The genetic diversity of the isolates was described using the (GTG)5 technique. About 75% percent (25/30) of the isolates reported the uspA marker confirming E. coli identity. Forty-eight percent (12/25) of the isolates reported the presence of the chuA marker, 20% (5/25) reported the cvaA marker, and 84% (21/25), 36% (9/25) and 56% (14/25) of the isolates reported the fimC, fyuA, and iucD markers, respectively. (GTG)5 analysis identified segregation of the bacterial isolates in two groups. These results reveal that most of the isolates contained VFGs and an large genetic diversity among the isolates.