Magneto-agglutination biosensor system for rapid detection of bacteria causing urinary tract infections

Globally, urinary tract infection (UTI) is very common and a primary reason for antibiotic prescribing. Currently, standard testing procedures involving laboratory culture of samples are slow and often patients are treated on symptoms alone, risking inappropriate treatment when not required. In this work, a novel biosensing system based on a magneto-agglutination assay is developed and evaluated. The system comprises an easy-to-use, multianalyte, urinalysis cartridge, and an instrument, which incorporates a fluid flow control unit, precision magnet movement and sensor coils plus magnetometers for each channel. The cartridge incorporates a range of features to ensure sensitive and reproducible measurement, from tolerating high variability in the volume of sample introduced to an in-built quality control mechanism through dynamic data capture. Measurement sensitivity for E.coli, Proteus and Klebsiella was high, with concentrations of pathogens as low as 10² CFUs quantified. In a small study on 30 patient urine samples, high clinical sensitivity was indicated. All 3 assay measurements (from urine sample input to result output) were completed in 7 min, making the magneto-agglutination biosensor system suitable for point-of-care applications.