Using in vitro, in vivo, and histopathological analyses to characterize the pathogenicity of novel APEC strains collected from colibacillosis cases from Georgia poultry populations | ASM Animal MicrobiologyThe pathogenicity of avian pathogenic Escherichia coli (APEC) in chickens has been ascribed primarily to serogroups O1, O2, and O78, with
no previous studies exploring the virulence of newer, novel APEC strains that have
been linked with recent poultry disease. Current commercial APEC vaccines only target
serogroups O1 and O78, and cross-protection remains limited. Therefore, understanding
how these novel APEC strains interact with the poultry host is critical. Moreover,
better animal challenge model studies are needed to develop new preventive plans against
these novel APEC serogroups. Our results show that while these novel APEC strains
cause high mortality in embryonic chicks, one APEC strain caused high mortality in
adult birds and was proven to be a primary pathogen. Also, these strains caused yolk
sac destruction, the critical organ for embryo development, potentially leading to
poor performance for the poultry production system. This study has used intensive
analysis and holistic assays to elucidate these novel APEC strains’ virulence, thereby
creating a better understanding of disease development.