Involvement of Lipoprotein NlpI in the Virulence of Adherent Invasive Escherichia coli Strain LF82 Isolated from a Patient with Crohn's Disease
AUTOR(ES)
Barnich, Nicolas
FONTE
American Society for Microbiology
RESUMO
Escherichia coli strain LF82 recovered from a chronic lesion of a patient with Crohn's disease (CD) is able to adhere to and invade cultured intestinal epithelial cells and to replicate within macrophages. One mutant selected for its impaired ability to invade epithelial cells had an insertion of a Tn phoA transposon within the nlpI gene encoding the lipoprotein NlpI. A NlpI-negative isogenic mutant showed a 35-fold decrease in its ability to adhere to and a 45-fold decrease in its ability to invade Intestine-407 cells, but its ability to survive and to replicate within macrophages was similar to that of wild-type strain LF82. In addition, this mutant did not express flagella and synthesized very small amounts of type 1 pili. Downregulation of type 1 pili in the NlpI-negative mutant resulted from a preferential switch toward the OFF position of the invertible DNA element located upstream of the fim operon. The FimB and FimE recombinases act in concert to control the switch, and a large decrease in fimB and fimE mRNA levels was observed. The absence of flagellar structures correlated with a drastic 19-fold decrease in the fliC mRNA level, regardless of the FlhD2C2 transcriptional regulator and of the σ28 transcription factor. The key role of NlpI in virulence is independent of type 1 pili and motility, since induced type 1 pilus expression and/or forced contact between bacteria and intestinal epithelial cells did not restore the ability of the NlpI mutant to adhere to and to invade intestinal epithelial cells.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=387872Documentos Relacionados
- HtrA Stress Protein Is Involved in Intramacrophagic Replication of Adherent and Invasive Escherichia coli Strain LF82 Isolated from a Patient with Crohn's Disease
- Invasive Ability of an Escherichia coli Strain Isolated from the Ileal Mucosa of a Patient with Crohn’s Disease
- Identification and Characterization of a New Lipoprotein, NlpI, in Escherichia coli K-12
- Adherent Invasive Escherichia coli Strains from Patients with Crohn's Disease Survive and Replicate within Macrophages without Inducing Host Cell Death
- Nutritional amblyopia in a patient with Crohn's disease.