Related Experiment Video
Updated: Jul 4, 2026
An In Vitro Bladder Model of Catheter-Associated Urinary Tract Infection
Published on: June 24, 2025
L-fucose-dependent biofilm formation by Escherichia coli enhances polymicrobial interactions and antibiotic tolerance
Steven M Taddei1, Namrata Deka1, Adam Marin1
1Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA.
Abstract:
Urinary tract infections are common healthcare associated infections, a large subset of which are caused by indwelling catheters. Long term catheterization causes persistent, asymptomatic, polymicrobial colonization despite catheters changes and antibiotic usage. In these polymicrobial populations, P. mirabilis, E. faecalis, and E. coli were found as the most common co-colonizing species. We investigated how interactions between P. mirabilis, E. coli, and E. faecalis contribute to biofilm formation and colonization of urinary catheters. Our results show that the interaction between these three species leads to enhanced biofilm biomass driven by an increase in total protein content of the biofilm. Biofilm enhancement required all three species and was also media-dependent, especially for dual-species combinations. Importantly, triple species biofilms also demonstrate biofilm enhancement when established under flow conditions in a biofilm reactor model using silicone urinary catheters. Additionally, triple species biofilm enhancement occurred in co-colonizing isolates from catheterized patients and was found to be specific to interactions between these three species. Triple species biofilms also demonstrated a species-dependent resistance to two commonly used antibiotics, ciprofloxacin and nitrofurantoin. By examining priority effects, E. coli was found to be the main facilitator of biofilm enhancement in a flow model. Finally, proteomics revealed that an L-fucose utilization pathway in E. coli was a key contributor to triple species biofilm enhancement. Overall, our results demonstrate the significant impact of polymicrobial interactions on biofilm formation in the catheterized environment and highlight ways in which complex microbial interplay and priority effects can shape the establishment of persistent colonization.
Insights
Polymicrobial interactions between three key bacteria significantly enhance urinary catheter biofilm formation and antibiotic resistance. Escherichia coli plays a crucial role in this process, particularly through its L-fucose utilization pathway.
Area of Science:
- Microbiology
- Infectious Diseases
- Biotechnology
Background:
- Urinary tract infections (UTIs) are common healthcare-associated infections, often linked to indwelling catheters.
- Long-term catheterization leads to persistent, asymptomatic polymicrobial colonization, even with interventions.
- Key co-colonizing species include *Proteus mirabilis*, *Enterococcus faecalis*, and *Escherichia coli*.
Purpose of the Study:
- To investigate the impact of interactions between *P. mirabilis*, *E. faecalis*, and *E. coli* on urinary catheter biofilm formation.
- To understand the mechanisms driving enhanced biofilm biomass and colonization in polymicrobial communities.
- To assess the role of microbial interactions in antibiotic resistance within catheter biofilms.
Main Methods:
- Utilized a biofilm reactor model with silicone urinary catheters under flow conditions.
- Analyzed biofilm biomass, total protein content, and species-specific contributions.
- Employed proteomics to identify key metabolic pathways involved in biofilm enhancement.
- Tested antibiotic resistance profiles of triple-species biofilms against ciprofloxacin and nitrofurantoin.
Main Results:
- Triple-species biofilms (*P. mirabilis*, *E. faecalis*, *E. coli*) exhibited significantly enhanced biomass compared to dual-species or single-species biofilms.
- Biofilm enhancement was dependent on the presence of all three species and specific media conditions.
- *E. coli* was identified as a key facilitator of biofilm enhancement, particularly under flow conditions.
- Proteomics revealed that an L-fucose utilization pathway in *E. coli* is critical for this enhancement.
- Triple-species biofilms showed increased resistance to ciprofloxacin and nitrofurantoin.
Conclusions:
- Polymicrobial interactions profoundly influence biofilm formation and colonization on urinary catheters.
- The interplay between *P. mirabilis*, *E. faecalis*, and *E. coli* drives enhanced biofilm development and antibiotic resistance.
- *E. coli*'s L-fucose utilization pathway is a significant factor in catheter-associated polymicrobial biofilm formation.
