[Pathogenetic aspects of urinary tract infection].

Most urinary tract infections are caused by Enterobacteriaceae; E. coli-strains dominating in 50 to 80% of primary infections. Microorganisms possessing the ability to colonize the uroepithelium (fimbriae/pili) and to cytotoxically damage of cells (hemolysin) may initiate acute infections. On the other hand, properties favouring the survival of these strains in the tissue (K-antigen, iron sequestering/aerobactin) tend to produce relapse and/or chronic infection. A variety of host-specific factors, especially glycosphingolipids, on the surface of epithelial cells determine the virulence of pathogenic microorganisms in the urinary tract and the course of a disease. Structural damages resulting from intra- or extrarenal obstructions, disturbances of the urinary flow and metabolic disorders are essential, predisposing factors of a host organism. These different factors and interactions of these mechanisms determine the manifestation and course of urinary tract infections.