Determination of Uropathogenic Escherichia coli in Urine by an Immunobiosensor Based Upon Antigen-Antibody Biorecognition with Fluorescence Detection and Bead-Injection Analysis

Abstract

Uroinfections, which are mainly caused by pathogenic bacteria, especially uro-pathogenic E. coli (UPEC), are among the major health problems in the modern world. The current gold standard for the identification of uroinfection causing pathogens in urine is microbiological cultivation, but uro-pathogens are also determined with quantitative polymerase chain reaction (qPCR) and matrix assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. However, it takes several hours or days to obtain the results. A promising option for rapid identification of pathogens is the application of biosensors. The aim of the current study was to develop a biosensor for the fast detection of UPEC in urine samples allowing achieving a limit of detection below 10³ CFU/mL, essential for the diagnostics of recurrent uroinfections and related diseases. First, the pathogens were attached onto a single use column and specifically detected using E. coli antibodies conjugated with a fluorescence marker. The bead-injection analysis platform for fluidics provided E. coli limits of detection and quantification in 150 µL urine samples <3 and <5 cells/mL, respectively. The time of analysis was 17 min. The biosensor results were in good correlation with the results obtained with other methods, indicating that the complex urine matrix of UPEC patients did not affect the biosensor measurements.

Keywords:

• Immunobiosensor
• uropathogenic Escherichia coli
• fluorescence
• bead-injection analysis

Acknowledgement

We thank Dr. Krista Lõivukene from the Tartu University Hospital for helping with microbiological analysis and providing UPEC positive urine samples.

Additional information

Funding

This work was supported by Estonian Research Council Grant No. IUT 20-17 and by the Graduate School of Functional Materials and Technologies receiving funding from the European Regional Development Fund at the University of Tartu, Estonia.