Type 1 fimbrial expression enhances Escherichia coli virulence for the urinary tract

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

Abstract

Type 1 fimbriae are adhesion organelles expressed by many Gram-negative bacteria. They facilitate adherence to mucosal surfaces and inflammatory cells in vitro, but their contribution to virulence has not been defined. This study presents evidence that type 1 fimbriae increase the virulence of Escherichia coli for the urinary tract by promoting bacterial persistence and enhancing the inflammatory response to infection. In a clinical study, we observed that disease severity was greater in children infected with E. coli O1:K1:H7 isolates expressing type 1 fimbriae than in those infected with type 1 negative isolates of the same serotype. The E. coli O1:K1:H7 isolates had the same electrophoretic type, were hemolysin-negative, expressed P fimbriae, and carried the fim DNA sequences. When tested in a mouse urinary tract infection model, the type 1-positive E. coli O1:K1:H7 isolates survived in higher numbers, and induced a greater neutrophil influx into the urine, than O1:K1:H7 type 1-negative isolates. To confirm a role of type 1 fimbriae, a fimH null mutant (CNI016) was constructed from an O1:K1:H7 type 1-positive parent. E. coli CNI016 had reduced survival and inflammatogenicity in the mouse urinary tract infection model. E. coli CNI016 reconstituted with type 1 fimbriae (E. coli CN1018) had restored virulence similar to that of the wild- type parent strain. These results show that type 1 fimbriae in the genetic background of a uropathogenic strain contribute to the pathogenesis of E. coli in the urinary tract.

Detaljer

Författare
Enheter & grupper
Externa organisationer
  • Technical University of Denmark
  • Göteborgs universitet
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Mikrobiologi inom det medicinska området

Nyckelord

Originalspråkengelska
Sidor (från-till)9827-9832
Antal sidor6
TidskriftProceedings of the National Academy of Sciences of the United States of America
Volym93
Utgivningsnummer18
StatusPublished - 1996 sep 3
PublikationskategoriForskning
Peer review utfördJa