Abstract

Avian pathogenic Escherichia coli (APEC) is one of the extra intestinal pathogenic E. coli (ExPEC). Previous studies showed that O1, O2 and O78 serotypes are mostly associated with Colibacillosis outbreaks, but recently there are emergent new pathogenic serotypes that have spread worldwide. Wide antigenic diversity exists among APEC strains in Egypt; however, the involvement of a particular O serotype in the infection process appears to vary with the geographical region. Different virulence genes have been identified in APEC. Recently; the presence of these virulence genes is being employed as an indication of pathogenicity, rather than the tedious E. coli serotyping methods. In Egypt; several virulence genes were studied, and were found to be different based on the geographical area. However; all studies were limited to a small number of screened virulence genes, in addition to the inconsistency of these screened genes. To control APEC, antibiotics have been used for decades; however the emergence of multi-drug resistant E. coli, and the difficulty of discovering new antimicrobial therapies made vaccine the best choice to control E. coli infections in poultry farms. In this review, the various aspects of APEC infection in poultry with special focus on the epidemiology of APEC in Egypt in relation to virulence traits were discussed. In addition, the most recent vaccination trials against the APEC diseases in poultry were discussed. We concluded that the virulence gene patterns of APEC can be considered as molecular markers of pathogenicity. Although of their current limitations, some vaccine trials showed promising results as good alternative to control colibacillosis in poultry.

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