Research Article
Azeem Riaz M*, Aslam A, Reh
Abstract
The objective of the present study the rfb gene clusters in avian pathogenic E. coli cardinal serotypes O1, O2 and O78 strains and to develop a multiplex polymerase chain reaction method for serotyping of the O-antigens. The multiplex polymerase chain reaction method was used for the identification of serotypes of APEC. The second part of the study was to study the pathological lesions caused by most prevalent sero group in experimentally infected broiler chicks. A total of 100 tissue samples (50 lungs and livers each) were collected from colibacillosis suspected broiler birds and subjected to isolation and identification of E. coli by conventional methods. Multiplex PCR was used for confirmation of three serogroups i.e., O1, O2 and O78. We found more O2 33% than O1 8% and O78 zero percent. These results suggested the prevalence of O2 sero group in our study. The prevalent sero group (O2) was experimentally inoculated in broiler birds at day 7 of their age. Lungs and liver samples from these experimentally infected birds were taken at days 14 and 21 of their age and subjected to histopathology. We found that there was hepatomegaly, coagulative necrosis, congestion and infiltration of inflammatory cells in infected livers. The lungs were congested and there were macrophages, lymphocytes and heterophils too. There was mostly hepatic form of colibacillosis with this infective strain.