Urinary tract infections can be severe, sometimes fatal, diseases whose etiological pathogens are predominantly uropathogenic strains of Escherichia coli (UPEC). To investigate the UPEC pathogenesis, several models have already been established with minor or major disadvantages. The aim od this thesis was to develop a simple, fast, and inexpensive biomimetic in vitro model based on normal porcine urothelial (NPU) cells that are genetically and physiologically similar to human bladder urothelium and to perform basic studies of E. coli pathogenicity. Initially, the model was tested using a set of control E. coli strains (J96, 536, SE15 and MG1655) and, subsequently, with human E. coli strains isolated either from urine of patients with urinary infections or from feces of healthy individuals. Pathogenicity of the individual strain tested was detrmined by viability of NPU cells. To visualize the subcellular events, transmission and scanning electron microscopy was performed. The strains were tested for the presence of different virulence-associated genes, phylogroup, type of core lipid, O-serotype, type of lipopolysaccharide, and ability to form biofilms. Statistical analysis of possible correlations between strains’ characteristics and the effect on survival of the NPU cells was performed. We also assessed the cytokine response of the NPU cells to different E. coli strains. Results showed that our model has the discriminatory power to distinguish pathogenic from non-pathogenic E. coli strains, and to identify new, potentially pathogenic strains and to reveal the cytokine response of the NPU cells.
|
