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Updated: Aug 5, 2025
Super-resolution Imaging of Proteus mirabilis Biofilm by Expansion Microscopy
Published on: July 18, 2025
Metabolic interplay between Proteus mirabilis and Enterococcus faecalis facilitates polymicrobial biofilm formation
Benjamin C Hunt1, Vitus Brix1, Joseph Vath1
1Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, 14203, United States of America.
Abstract:
Polymicrobial biofilms play an important role in the development and pathogenesis of CAUTI. Proteus mirabilis and Enterococcus faecalis are common CAUTI pathogens that persistently co-colonize the catheterized urinary tract and form biofilms with increased biomass and antibiotic resistance. In this study, we uncover the metabolic interplay that drives biofilm enhancement and examine the contribution to CAUTI severity. Through compositional and proteomic biofilm analyses, we determined that the increase in biofilm biomass stems from an increase in the protein fraction of the polymicrobial biofilm matrix. We further observed an enrichment in proteins associated with ornithine and arginine metabolism in polymicrobial biofilms compared to single-species biofilms. We show that L-ornithine secretion by E. faecalis promotes arginine biosynthesis in P. mirabilis, and that disruption of this metabolic interplay abrogates the biofilm enhancement we see in vitro and leads to significant decreases in infection severity and dissemination in a murine CAUTI model.
Insights
This study reveals how common urinary tract infection bacteria, Proteus mirabilis and Enterococcus faecalis, enhance polymicrobial biofilms through metabolic cooperation. Disrupting this interaction reduces infection severity and spread.
Area of Science:
- Microbiology
- Infectious Diseases
- Biochemistry
Background:
- Polymicrobial biofilms are key in catheter-associated urinary tract infections (CAUTI).
- Proteus mirabilis and Enterococcus faecalis are prevalent CAUTI pathogens that form robust biofilms.
- These polymicrobial biofilms exhibit increased biomass and antibiotic resistance.
Purpose of the Study:
- To investigate the metabolic interplay driving enhanced polymicrobial biofilm formation.
- To examine the contribution of this interplay to CAUTI pathogenesis and severity.
Main Methods:
- Compositional and proteomic analyses of single-species and polymicrobial biofilms.
- In vitro assessment of metabolic interactions between E. faecalis and P. mirabilis.
- In vivo murine CAUTI model to evaluate infection severity and dissemination.
Main Results:
- Polymicrobial biofilms showed increased protein content in the matrix, contributing to biomass.
- Enrichment of ornithine and arginine metabolism proteins was observed in polymicrobial biofilms.
- E. faecalis L-ornithine secretion promotes P. mirabilis arginine biosynthesis, enhancing biofilms.
Conclusions:
- A specific metabolic crosstalk between E. faecalis and P. mirabilis drives polymicrobial biofilm enhancement.
- Disrupting this L-ornithine/arginine metabolic interplay significantly reduces in vitro biofilm formation.
- Interference with this pathway decreases CAUTI severity and dissemination in a murine model.
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