Type 1 pili-mediated adherence of Escherichia coli strain LF82 isolated from Crohn's disease is involved in bacterial invasion of intestinal epithelial cells
Article first published online: 24 FEB 2004
Volume 39, Issue 5, pages 1272–1284, March 2001
How to Cite
Boudeau, J., Barnich, N. and Darfeuille-Michaud, A. (2001), Type 1 pili-mediated adherence of Escherichia coli strain LF82 isolated from Crohn's disease is involved in bacterial invasion of intestinal epithelial cells. Molecular Microbiology, 39: 1272–1284. doi: 10.1111/j.1365-2958.2001.02315.x
- Issue published online: 24 FEB 2004
- Article first published online: 24 FEB 2004
- Accepted 11 December, 2000.
We previously characterized the invasive ability of Escherichia coli strain LF82, isolated from an ileal biopsy of a patient with Crohn's disease. In the present study, we performed TnphoA insertion mutagenesis to identify genes involved in LF82 invasion of intestinal epithelial cells. Most of the non-invasive mutants had an insertion mutation within the type 1 pili-encoding operon. Two non-invasive fim mutants, which harboured an insertion within the fimI and fimF genes, still adhered but had lost the ability to induce host cell membrane elongations at the sites of contact with the epithelial cells. Transcomplementation experiments with a fim operon cloned from E. coli K-12 restored both invasive ability and the ability to induce host cell membrane elongations. Expression of the cloned LF82 or K-12 fim operon into the non-invasive laboratory strain JM109 did not confer invasive properties. Thus, these findings showed that: (i) type 1 pili-mediated adherence is involved in LF82-induced perturbation of host cell signalling responsible for membrane elongations; (ii) native shafts are required for type 1 pilus-mediated induction of membrane elongations; (iii) this active phenomenon is a key step in the establishment of the invasive process; and (iv) type 1 pili alone are not sufficient to trigger bacterial internalization.