Avian pathogenic Escherichia coli (APEC) causes colibacillosis, which is one of the main causes of
economic losses in the poultry industry worldwide. This disease occurs only when the E. coli infecting
strain presents virulence factors (encoded by specific genes) that enable the adhesion and proliferation
in the host organism. Herin, 15 E. coli strains of different serogroups isolated from birds with
colibacillosis were assigned to their phylogenetic groups and analyzed for the occurrence of 11
virulence associated genes. phylogenetic typing showed that group B2 was the largest (33.3%, 5/15)
followed by group B1 (26.7%, 4/15), groups A and D were similar in size (22.1%, 19/86). The virulence
profiles showed that ompA was found in most isolates 14/15 (93.3%). The iss gene was found in13/15
(86.6%). Followed by traT and iutA genes which were found in12/15 (80%). cvaC, stx2 and tsh genes
were present in 9/15(60%), 7/15(46%) and of the isolates, respectively. Only one isolate gave positive
amplification for stx1 and ibeA genes each. The hly gene was not encountered in any of the tested
isolates.