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Updated: Jul 8, 2026

Establishment and Characterization of UTI and CAUTI in a Mouse Model
08:40

Establishment and Characterization of UTI and CAUTI in a Mouse Model

Published on: June 23, 2015

The high-affinity phosphate transporter Pst is a virulence factor for Proteus mirabilis during complicated urinary

Sandra M Jacobsen1, Mary C Lane, Jean M Harro

  • 1Department of Microbiology and Immunology, School of Medicine, University of Maryland Baltimore, Baltimore, MD, USA.

FEMS Immunology and Medical Microbiology
|January 16, 2008
PubMed

Insights

The Pst transporter is crucial for Proteus mirabilis virulence in urinary tract infections (UTIs). This high-affinity phosphate transporter provides an in vivo advantage, though it is not essential for bacterial growth in vitro.

Area of Science:

  • Microbiology
  • Bacterial Pathogenesis
  • Molecular Biology

Background:

  • Proteus mirabilis is a common cause of complicated urinary tract infections (UTIs).
  • Phosphate uptake is essential for bacterial survival and is tightly regulated.
  • The high-affinity phosphate transporter (Pst) system and its regulation are key to bacterial adaptation.

Purpose of the Study:

  • To investigate the role of the Pst transporter in the virulence of Proteus mirabilis during UTIs.
  • To determine if the Pst system is essential for in vitro growth or provides an in vivo advantage.

Main Methods:

  • Generated Pst transporter mutants (pstS, pstA) of Proteus mirabilis HI4320 using transposon mutagenesis.
  • Assessed bacterial growth in vitro under various conditions (rich broth, minimal media, human urine) and in vivo using a CBA mouse model of ascending UTIs.
  • Analyzed alkaline phosphatase (AP) production as an indicator of phosphate regulation.

Main Results:

  • Mutants lacking functional Pst transporter constitutively produced alkaline phosphatase, indicating dysregulated phosphate homeostasis.
  • Pst mutants showed no significant growth defects in vitro.
  • Pst mutants exhibited reduced colonization in the mouse bladder compared to wild-type, but complementation restored colonization ability.

Conclusions:

  • The Pst transport system confers a significant in vivo advantage to Proteus mirabilis during UTI pathogenesis.
  • The Pst transporter acts as a virulence factor, satisfying molecular Koch's postulates.
  • Targeting the Pst transporter could be a potential therapeutic strategy for P. mirabilis UTIs.

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