Bacterial etiologic agents in the pathogenesis of urinary tract infection

Most of the information available concerning virulence factors of uropathogens is based on studies of Escherichia coli, the commonest cause of urinary tract infections. Earlier studies revealed several phenotypic Escherichia coli virulence factors that influenced both the anatomic level and severity of urinary tract infection. Virulence factors included O antigen serotype, presence and quantity of K capsular polysaccharide, adherence to uroepithelial cells, resistance to serum bactericidal activity, hemolysin, and aerobactin production. The introduction of DNA hybridization methodology has provided a valuable tool for reevaluation of the epidemiology of Escherichia coli infection as well as an alternative to the conventional phenotypic approach for studying the genotypic basis for virulence.