RESUMO
Objective: to determine the frequency of potential virulence factors in Escherichia coli isolates from avian colibacillosis
Design: descriptive study
Samples: one hundred E. coli isolates from cases of avian colibacillosis examined in this study were obtained from the bacterial collection of Poultry Diseases Section, Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Tehran
Procedure: all isolates were characterized with respect to motility, serum resistance and ability to produce aerobactin, colicin, colicin V and hemolysin
Results: no hemolytic isolate was found. Motility and serum resistance were found in 64 and 94% of isolates, respectively. The percentages of isolates that produced aerobactin, colicin and colicin V were 85, 90 and 22%, respectively
Conclusion: aerobactin production and serum resistance may be important factors associated with virulence of avian E. coli isolates