Preliminary MLST studies on ExPEC isolates of human and animal origin have shown that the K1-positive-capsule of APEC and NMEC isolates have a very identical Phylogenetic background. This information together with an almost non-differentiable virulence gene pattern would therefore raise questions about the potential zoonotic risk of APEC, and also whether the assumed host specificity of ExPEC pathovars to date really exists. To answer this, one of the dissertation topics in our group is therefore based on the following approaches: (I) Functional comparative studies of APEC and NMEC with regards to their invasiveness in vitro using Human (HBMEC) and avian cell lines, as well as in vivo through chicken infections. (II) Deletion of Invasion-associated genes (ibeA, ibeB und ompA) from APEC and NMEC and then testing the invasion ability of the mutants in vitro as also their virulence in vivo. (III) To try and explain the origin of APEC and NMEC strains with respect to their relatedness using MLST, as well as the sequence analysis of the invasion-associated genes ompA and ibeB.
Infection of HBMEC (Human Brain Endothelial Cells) [blue: Actin structure; red: Cell nucleus] with APEC-strain IMT5155 [green]