Development of a New System for Bacterial Load Detection in Water Samples Exploiting ATP Chemiluminescence Reaction

In this work, we present an innovative system for the rapid detection of bacterial contamination in water samples, exploiting chemiluminescence reaction in the presence of bacterial adenosine triphosphate (ATP). It is formed by a closed box in which reagents and ATP from water samples are put in a spectrophotometric-grade quartz cuvette on a silicon photomultiplier (SiPM) that converts the photons revealed into electrical signals. A commercial kit for bacterial load detection in water samples employing ATP chemiluminescent reaction was tested, and its filtration and lysis efficiencies were assessed. A comparison between the new system and the luminometer, the standard device for chemiluminescence detection, was then conducted. Firstly, calibration curves for both systems were obtained using different ATP concentrations, resulting in a Limit of Detection (LoD) of 0.03 nM for the SiPM-based system and 0.01 nM for the luminometer. Afterwards, water samples artificially contaminated with E. coli were prepared to compare the detection efficiency of both systems using the commercial kit for sample processing. A cultural method analysis was also conducted to validate the obtained results. ATP concentrations derived from the three detection strategies showed great consistency, underlying the high sensitivity of the new low-cost, miniaturizable and potentially remotely controlled system developed.