Occurrence of Escherichia coli virulence genes in feces of wild birds from Central Italy

ABSTRACT

Objective: To investigate the potential role of wild birds as fecal spreaders of enteropathogenic, enterohemorrhagic and Shiga-toxins producing Escherichia coli (E. coli), enteropathogenic E. coli, enterohemorrhagic E. coli and Shiga toxin-producing E. coli strains. Methods: Fecal samples collected from 121 wild birds of different orders and species were submitted to molecular analyses. In particular, eaeA encoding intimin, hlyA encoding for hemolysin, stx1 and stx2 genes encoding Shiga-toxins 1 and 2, respectively, were investigated. Results: Overall, 21(17.35%) fecal samples resulted positive for at least one of the investigated genes. In detail, 12(9.91%) samples were positive for eaeA, 10(8.26%) for stx1, 4(3.31%) for hylA and 1(0.83%) for stx2. An owl (Athene noctua) positive for the four investigated genes suggesting that it harbored a STEC strain. However, virulence genes characterizing EPEC, and EHEC strains were mainly found among seagulls, waterfowl and feral pigeons. Conclusions: Seagulls, waterfowl and feral pigeons, which frequently reach and contaminate rural, urban and peri-urban areas with their droppings, may be important sources of E. coli infection for other animals and humans.