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Updated: Jul 24, 2025
Detection of Bacteria Using Fluorogenic DNAzymes
Published on: May 28, 2012
Flow cytometric detection of vancomycin-resistant Enterococcus faecium in urine using fluorescently labelled
Thomas F Oftedal1, Dzung B Diep2
1Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway. thof@nmbu.no.
Abstract:
A urinary tract infection (UTI) occurs when bacteria enter and multiply in the urinary system. The infection is most often caused by enteric bacteria that normally live in the gut, which include Enterococcus faecium. Without antibiotic treatment, UTIs can progress to life-threatening septic shock. Early diagnosis and identification of the pathogen will reduce antibiotic use and improve patient outcomes. In this work, we develop and optimize a cost-effective and rapid (< 40 min) method for detecting E. faecium in urine. The method uses a fluorescently labelled bacteriocin enterocin K1 (FITC-EntK1) that binds specifically to E. faecium and is then detected using a conventional flow cytometer. Using this detection assay, urine containing E. faecium was identified by an increase in the fluorescent signals by 25-73-fold (median fluorescence intensity) compared to control samples containing Escherichia coli or Staphylococcus aureus. The method presented in this work is a proof of concept showing the potential of bacteriocins to act as specific probes for the detection of specific bacteria, such as pathogens, in biological samples.
Insights
A new rapid method detects Enterococcus faecium (E. faecium) in urine using a fluorescent bacteriocin probe. This early detection of E. faecium can improve patient outcomes and reduce antibiotic use.
Area of Science:
- Microbiology
- Biotechnology
- Medical Diagnostics
Background:
- Urinary tract infections (UTIs) are common and can lead to severe complications like septic shock if untreated.
- Enterococcus faecium (E. faecium) is a frequent cause of UTIs, necessitating accurate and timely pathogen identification.
- Current diagnostic methods can be slow, delaying appropriate antibiotic treatment and potentially increasing antibiotic resistance.
Purpose of the Study:
- To develop a rapid, cost-effective method for detecting E. faecium in urine samples.
- To utilize bacteriocins as specific probes for bacterial identification.
- To demonstrate the potential of this method for early UTI diagnosis and improved patient management.
Main Methods:
- Development of a fluorescently labeled bacteriocin, enterocin K1 (FITC-EntK1), for specific binding to E. faecium.
- Optimization of a detection assay using conventional flow cytometry.
- Testing the assay with urine samples spiked with E. faecium, Escherichia coli, and Staphylococcus aureus.
Main Results:
- The FITC-EntK1 assay detected E. faecium with a 25-73-fold increase in median fluorescence intensity compared to controls.
- The method achieved detection in under 40 minutes, demonstrating its rapidity.
- The assay showed specificity for E. faecium against other common urinary bacteria.
Conclusions:
- Bacteriocins can serve as effective, specific probes for detecting bacterial pathogens in biological samples.
- This novel method offers a promising approach for rapid E. faecium detection in urine, aiding early UTI diagnosis.
- The developed assay has the potential to reduce unnecessary antibiotic use and improve clinical outcomes for UTI patients.
