[Escherichia coli virulence factors in pediatric urinary tract infections]

As many as 90% of all community-acquired urinary tract infections (UTIs) and more than 30% of nosocomially acquired UTIs are caused by E coli. The migration of bacteria into proximal urethra and bladder mucosa requires that the organisms travel "upstream" and resist being carried away by the flow of urine. Colonisation requires binding of specific adhesions of the bacteria to appropriate receptors on the surfaces of the epithelial cells. P fimbrae are found in 80%, 30% and 20% of strains from patients with pyelonephritis, cystitis and asymptomatic bacteriura, respectively. P fimbrae are found in only 30% of strains isolated from patients with pyelonephritis associated with compromising host factors such as vesicoureteral reflux, urinary tract anatomical abnormalities and recent urinary tract instrumentation.