Study of some virulence factors in Escherichia coli strains of animal origin

Abstract

The present study investigated Escherichia coli (E. coli) strains isolated from chickens in Algeria, focusing on their virulence factors and antibiotic resistance profiles. Avian pathogenic E. coli (APEC) is the primary causative agent of avian colibacillosis, a prevalent disease affecting chicken populations globally. Despite the identification of multiple virulence-associated factors, in Algeria, little information has been available on virulence potential and antibiotics resistance of avian E. coli isolates. Therefore, the aim of this study was the characterization of virulence genes and antibiotic resistance profile of Algerian E. coli strains isolated from diseased broilers. In this research, 23 of Escherichia coli isolates were recovered from broilers exhibiting clinical signs and lesions of colibacillosis. The investigation examined the presence of virulence factors such as curli production according to CR binding and hemolysis, indicative of APEC's pathogenic potential. Curli, adhesive surface structures facilitating bacterial attachment and hemolysis ability to lyse red blood cells, were assessed for their roles in tissue damage and disease progression. The prevalence was (82.7%) curliated isolates, (17.39%) non curliated isolated added to it hemolysis test were (21.74%) non hemolytic, (78.26%) were alpha hemolytic. Furthermore, five key virulence genes were analyzed with PCR :( iss, iron, hlyF, ompt, and iutA) These genes, responsible for factors critical to APEC's pathogenicity, including adherence to host cells, iron acquisition, toxin production, and evasion of host immune responses, were investigated to understand the genetic determinants underlying APEC's virulence and pathogenesis. Reports showed that 99% of the examined isolates host at least two of the tested virulence factors. The most prevalent genes were: iss (86.95%), iroN (100%) the highest prevalence, Ompt (91.30%), hlyF (78.26%), iut A (82.60%) considered as lower rates Additionally, 17 antibiotics were used to detect sensibility and resistance were determined for 23 isolates were (100%) resistant to ampicillin and (100%) sensitive to cefazolin / cefoxitin / cefotaxime / ceftazidime / ertapenem / imipenem / Amikaracin / Gentamicin / Fosfomycin. Were the most efficient antibiotics against the analyzed pathogene Echerichia coli isolates. Overall, these findings provide more insights about avian pathogenic E.coli virulence potential in Algeria which could participate in the fight against colibacillosis