Simultaneous detection of dual targets Escherichia coli and Salmonella enteritidis using enzyme-free strand displacement reaction

Escherichia coli (E. coli) and Salmonella enteritidis (S. enteritidis) are common food-borne pathogens, which pose a very significant threat to the healthcare environment. The rapid detection of relevant bacteria can help control their rapid spread, while the traditional bacterial culture detection method is time-consuming and not conducive to the rapid detection of pathogens. Recently, new detection methods for related pathogenic bacteria have emerged, but these methods are relatively complex, and few methods can detect two bacteria at the same time. Therefore, there is an urgent need to develop multi-target, convenient, and fast pathogen detection methods. This method successfully constructed an enzyme-free fluorescent biosensor based on the adapter-mediated strand displacement reaction to detect E. coli ATCC25922 and S. enteritidis ATCC13076. This method had an ultrasensitive detection limit of 0.7 CFU/mL and 0.61 CFU/mL within 20 min, with a broad linear range of 34–10⁵ CFU/mL of E. coli and 17–10⁶ CFU/mL of S. enteritidis, respectively. Importantly, the spiked recovery of the three clinical fluid samples performed well, which proved that this method had the potential to detect E. coli and S. enteritidis in clinical samples. The sensor constructed by this method can detect dual targets at the same time, increasing the possibility of large-scale clinical use.