Virulence factors of Escherichia coli contribute to acute renal failure

Background: The development of acute renal failure (ARF) significantly enha nces the mortality of patients with Gram-negative septic shock. The role of specific bacterial virulence factors different from lipopolysaccharides (L PS) in the deterioration of renal function in septic shock remains to be de termined. Methods: An Escherichia coli wild-type strain (536/21 WT, 06:K15: H31) was isolated from a patient suffering from a urinary tract infection. The strain expresses various virulence factors (e.g, hemolysin, fimbriae) g enetically encoded by pathogenicity islands. The spontaneous deletion mutan t 536/ 21 Del lacks the expression of these virulence factors. Isolated rat kidneys were perfused with a suspension (5 x 10(4)/ml) of the respective s train or control perfusion medium and the renal functional parameters were analyzed. Intrarenal deposition of E. coli was detected by immunohistology and Gram staining. Results: The perfusion of the isolated perfused rat kidn ey with a uropathogenic E. coli wild-type strain (536/21 WT) caused an acut e deterioration of renal function which was not observed in kidneys exposed to a deletion mutant of E, coli 536/21 lacking the expression of virulence factors. The glomerular filtration rate and the urine flow rate significan tly decreased only in kidneys perfused with the E. coli wild-type strain, w hile there was no change versus controls in kidneys perfused with the delet ion mutant. Conclusions: Distinctive bacterial virulence factors different from LPS such as hemolysin and the presence of different fimbriae may contr ibute to the development of ARF in sepsis induced by E. coli, Anti-LPS stra tegies may not be sufficient to reduce the risk of ARF in Gram-negative sep tic shock. Copyright (C) 1999 S. Karger AG, Basel.