Research note: Prevalence and genetic characteristics of pathogenic E. coli isolates from domestic pigeons in central China.

Pigeon has become popular as a food recently, due to their highly nutritive valuE. colibacillosis, which is caused by pathogenic E. coli, is one of the most important bacterial diseases in pigeon breeding. However, data on E. coli isolates from pigeons are currently limited. In order to understand the prevalence and genetic characteristics of pathogenic E. coli in pigeon farms, a total of 199 E. coli strains were isolated from domestic pigeons in central China. Among them, 30.15 % isolates (60/199) were identified to belong to phylogroups B2 and D, which were recognized as pathogenic E. coli. To further characterize these 60 pathogenic E. coli, whole genome sequencing and antimicrobial susceptibility testing were carried out. These isolates covered 12 serotypes, and the dominant serotypes were O166 (30/60), O17 (7/60) and O7 (7/60). Eleven sequence types (ST) were identified, and ST646, ST38 and ST2001 were the dominant genotypes. Among these 60 pathogenic E. coli strains, high resistance rates to florfenicol (96.7 %), tetracycline (96.7 %), ampicillin (98.3 %) and trimethoprim (96.7 %) were observed. Twenty-six resistance genes were identified, and the most popular resistance genes included floR (58/60), tetA (58/60), bla (58/60), dfrA (57/60) and sul2 (53/60). Virulence gene analysis revealed five different iron uptake systems in these strains, and all the O166 serotype strains contained three iron uptake systems. In addition, diarrhoeagenic E. coli-associated gene eaeH was detected in 96.67 % of the pathogenic isolates, highlighting their foodborne threat. Overall, this study extends our knowledge of the epidemiology of pathogenic E. coli in domestic pigeons.