Development of intracellular bacterial communities of uropathogenic Escherichia coli depends on type 1 pili.


Journal Article

Uropathogenic Escherichia coli, the predominant causative agent of urinary tract infections, use type 1 pili to bind and invade bladder epithelial cells. Upon entry, the bacteria rapidly replicate and enter a complex developmental pathway ultimately forming intracellular bacterial communities (IBCs), a niche with biofilm-like properties protected from innate defences and antibiotics. Paradoxically, bacteria within IBCs produce type 1 pili, an organelle thought only to be an extracellular colonization factor. Thus, we investigated the function of type 1 pili in IBC development. The cystitis isolate, UTI89, was genetically manipulated for conditional fim expression under control of the tet promoter. In this strain, UTI89-tetR/P(tet) fim, piliation is constitutively inhibited by the tetracycline repressor, TetR. Repression is relieved by anhydrotetracycline (AHT) treatment. UTI89-tetR/P(tet) fim and the isogenic control strain, UTI89-tetR, grown in the presence of AHT, colonized the bladder and invaded the superficial umbrella cells at similar levels at early times in a murine model of infection. However, after invasion UTI89-tetR/P(tet) fim became non-piliated and was unable to form typical IBCs comprised of tightly packed, coccoid-shaped bacteria in contrast to the control strain, UTI89-tetR. Thus, this work changes the extracellular colonization functional paradigm of pili by demonstrating their intracellular role in biofilm formation.

Full Text

Cited Authors

  • Wright, KJ; Seed, PC; Hultgren, SJ

Published Date

  • September 2007

Published In

Volume / Issue

  • 9 / 9

Start / End Page

  • 2230 - 2241

PubMed ID

  • 17490405

Pubmed Central ID

  • 17490405

International Standard Serial Number (ISSN)

  • 1462-5814

Digital Object Identifier (DOI)

  • 10.1111/j.1462-5822.2007.00952.x


  • eng

Conference Location

  • England