The Type 1 Pili Regulator Gene fimX and Pathogenicity Island PAI-X as Molecular Markers of Uropathogenic Escherichia Coli

Microbiology. 2013 Aug;159(Pt 8):1606-1617. doi: 10.1099/mic.0.066472-0. Epub 2013 Jun 6.


Uropathogenic Escherichia coli (UPEC) fall within a larger group of isolates producing extraintestinal disease. UPEC express type 1 pili as a critical virulence determinant mediating adherence to and invasion into urinary tract tissues. Type 1 pili expression is under regulation by a family of site-specific recombinases, including FimX, which is encoded from a genomic island called PAI-X for pathogenicity island of FimX. Using a new multiplex PCR, fimX and the additional PAI-X genes were found to be highly associated with UPEC (144/173 = 83.2 %), and more prevalent in UPEC of lower urinary tract origin (105/120 = 87.5 %) than upper urinary tract origin (39/53 = 74 %; P<0.05) or commensal isolates (28/78 = 36 %; P≤0.0001). The Fim-like recombinase gene fimX is the only family member that has a significant association with UPEC compared to commensal isolates. Our results indicate PAI-X genes, including the type 1 pili regulator gene fimX, are highly prevalent among UPEC isolates and have a strong positive correlation with genomic virulence factors, suggesting a potential role for PAI-X in the extraintestinal pathogenic E. coli lifestyle.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomarkers*
  • Escherichia coli Proteins / genetics*
  • Fimbriae, Bacterial / genetics*
  • Genomic Islands*
  • Polymerase Chain Reaction
  • Recombinases / genetics*
  • Uropathogenic Escherichia coli / genetics*


  • Biomarkers
  • Escherichia coli Proteins
  • FimX protein, E coli
  • Recombinases