Sat, the secreted autotransporter toxin of uropathogenic Escherichia coli, is a vacuolating cytotoxin for bladder and kidney epithelial cells.
The secreted autotransporter toxin (Sat) of uropathogenic Escherichia coli exhibits cytopathic activity upon incubation with HEp-2 cells. We further investigated the effects of Sat on cell lines more relevant to the urinary tract, namely, those derived from bladder and kidney epithelium. Sat elicited elongation of cells and apparent loosening of cellular junctions upon incubation with Vero kidney cells. Additionally, incubation with Sat triggered significant vacuolation within the cytoplasm of both human bladder (CRL-1749) and kidney (CRL-1573) cell lines. This activity has been associated with only a few other known toxins. Following transurethral infection of CBA mice with a sat mutant, no reduction of CFU in urine, bladder, or kidney tissue was seen compared to that in mice infected with wild-type E. coli CFT073. However, significant histological changes were observed within the kidneys of mice infected with wild-type E. coli CFT073, including dissolution of the glomerular membrane and vacuolation of proximal tubule cells. Such damage was not observed in kidney sections of mice infected with a Sat-deficient mutant. These results indicate that Sat, a vacuolating cytotoxin expressed by uropathogenic E. coli CFT073, elicits defined damage to kidney epithelium during upper urinary tract infection and thus contributes to pathogenesis of urinary tract infection.
Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore 21201, USA.
Debra M
DM
Guyer
Suzana
S
Radulovic
Faye-Ellen
FE
Jones
Harry L T
HL
Mobley
D000818:Animals; D001427:Bacterial Toxins / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D002522:Chlorocebus aethiops; D003593:Cytoplasm / Q000473:pathology; D003603:Cytotoxins / Q000378:metabolism*; D004195:Disease Models, Animal; D004847:Epithelial Cells / Q000473:pathology; D004926:Escherichia coli / Q000378:metabolism*; D004927:Escherichia coli Infections / Q000473:pathology; D005260:Female; D006801:Humans; D007668:Kidney / Q000473:pathology*; D051379:Mice; D008808:Mice, Inbred CBA; D011704:Pyelonephritis / Q000382:microbiology; D013997:Time Factors; D001743:Urinary Bladder / Q000473:pathology*; D014617:Vacuoles; D014709:Vero Cells
D001427:Bacterial Toxins; D002352:Carrier Proteins; D003603:Cytotoxins