Biosensing Strategies for Bacterial Detection and Antimicrobial Susceptibility Testing: A Narrative Review

Background: Growing research interest has focused on biosensing platforms as rapid, sensitive and economically advantageous tools for bacterial identification and antimicrobial resistance or susceptibility assessment in microbiological diagnostics. Conventional microbiological workflows remain essential reference methods but may require extended incubation and processing times. A wide range of biosensing strategies has therefore been investigated to accelerate bacterial detection and the assessment of antimicrobial response. Methods: This narrative review examines biosensing approaches relevant to bacterial detection and AST, including living-cell and whole-cell biosensors, electrochemical and impedimetric platforms, optical biosensors, bacteriophage-based systems, immunosensors, aptamer-based technologies, microfluidic approaches, and CRISPR-associated molecular detection. Particular attention is given to the distinction between platforms in which living cells function as sensing elements and systems in which bacterial cells or bacterial components represent the analytical target. Results: Reported analytical performance varied considerably according to bacterial species, recognition element, transduction strategy, sample matrix, sample-preparation requirements, and validation design. Selected experimental platforms achieved rapid detection or antimicrobial-response measurements; however, many studies were performed using buffer systems, artificially spiked samples, or relatively limited collections of bacterial isolates. Phenotypic AST platforms, molecular resistance-detection systems, and bacterial-identification technologies provide different types of information and should therefore not be considered interchangeable. Translation into routine microbiology remains limited by challenges related to sample preparation, reproducibility, sensor stability, standardization, validation against reference methods, and integration into clinical workflows. Conclusions: Cell-based and related biosensing approaches show potential to complement conventional microbiological methods, but further standardisation, validation and integration into routine workflows are required before widespread clinical implementation.