The interaction of urinary tract infection and renal insufficiency.

Urinary tract infections (UTIs) are among the most common infections caused by microorganisms, and pyelonephritis is the most severe infection of the urogenital tract. The risk of developing chronic renal insufficiency due to a UTI without other risk factors is low. The pathogenicity and virulence of the infective microorganisms as well as the efficiency of local or systemic defence mechanisms determine the course and severity of the disease. Virulence properties (adhesins, toxins, capsule, iron uptake) are encoded by genomic structures and the determination of virulence is influenced by the host situation. In renal insufficiency, a variety of quite different substances (uraemic toxins, betaine, amino acids, creatinine, urea, glucose) influence the microbial environment. Defence factors (Tamm-Horsfall protein, defensin, phagocytic activity of granulocytes) and underlying anatomical lesions as well as pre-existing renal disease determine the severity of UTI and the prognosis of renal insufficiency.