Pennsylvania Animal Diagnostic Laboratory System
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Identifying markers for distinguishing avian pathogenic E. coli strains

Chitrita DebRoy, Sean Altecruz, Suzanne Myers, Sabrina Reilley, Tara Tiffany, Jocelyn Torcolini, Danielle Needle, Mike Davis

Gastroenteric Disease Center
Penn State, University Park, PA 16802

We examined 105 E. coli strains collected from turkeys with colibacillosis and 166 normal fecal E. coli isolates from randomly selected finisher flocks and brooder flocks. The serotyping of these isolates showed that O78 was the principle serogroup associated with clinical isolates followed by O2, O114, O8 and O1 respectively. The serogroups of fecal isolates did not correspond to the serogroups observed for the clinical isolates. The strains were characterized for the presence of four potential virulence genes for increased serum survival (iss), temperature sensitive hemagglutination (tsh), hemolysin (HlyE) and K1 capsular antigen. Iss and K1 genes were more common among pathogenic than the fecal E. coli isolates. Serum resistance for a subset of 24 clinical isolates was examined. None of them exhibited resistance to serum although all of them carried the iss gene. The plasmid profile of these 24 clinical isolates and 6 environmental isolates reflected the presence of several plasmids. Some common plasmids were observed between the strains. Further work is being conducted to see which plasmids in clinical and environmental isolates carry the iss gene by southern blotting.

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