Pyelonephritogenic diffusely adhering Escherichia coli EC7372 harboring Dr-II adhesin carries classical uropathogenic virulence genes and promotes cell lysis and apoptosis in polarized epithelial caco-2/TC7 cells.
Diffusely adhering Escherichia coli (DAEC) strains expressing adhesins of the Afa/Dr family bind to epithelial cells in a diffuse adherence pattern by recognizing a common receptor, the decay-accelerating factor (CD55). Recently, a novel CD55-binding adhesin, named Dr-II, was identified from the pyelonephritogenic strain EC7372. In this report, we show that despite the low level of sequence identity between Dr-II and other members of the Afa/Dr family, EC7372 induces pathophysiological effects similar to those induced by other Afa/Dr DAEC strains on the polarized epithelial cell line Caco-2/TC7. Specifically, the Dr-II adhesin was sufficient to promote CD55 and CD66e clustering around adhering bacteria and apical cytoskeleton rearrangements. Unlike other Afa/Dr DAEC strains, EC7372 expresses a functional hemolysin that promotes a rapid cellular lysis. In addition, cell death by apoptosis or necrosis was observed in EC7372-infected Caco-2/TC7 cells, depending on infection time. Our results indicate that EC7372 harbors a pathogenicity island (PAI) similar to the one described for the pyelonephritogenic strain CFT073, which carries both hly and pap operons. Cumulatively, our findings indicate that strain EC7372 can be considered a prototype of a subclass of Afa/Dr DAEC isolates that have acquired a PAI harboring several classical uropathogenic virulence genes.
Guignot
J
J
Unité 510, Faculté de Pharmacie Paris XI, Institut National de la Santé et de la Recherche Médicale, F-92296 Châtenay-Malabry, France.
Breard
J
J
Bernet-Camard
M F
MF
Peiffer
I
I
Nowicki
B J
BJ
Servin
A L
AL
Blanc-Potard
A B
AB
D018830:Adhesins, Escherichia coli / Q000502:physiology*; D017209:Apoptosis; D001422:Bacterial Adhesion; D018958:CD55 Antigens / Q000502:physiology*; D018938:Caco-2 Cells; D016764:Cell Polarity; D004926:Escherichia coli / Q000235:genetics / Q000472:pathogenicity*; D006460:Hemolysin Proteins / Q000502:physiology; D006801:Humans; D009336:Necrosis; D011704:Pyelonephritis / Q000209:etiology*; D013997:Time Factors; D014774:Virulence
D018830:Adhesins, Escherichia coli; D018958:CD55 Antigens; D006460:Hemolysin Proteins