Rapid Quantitative Detection of Salmonella spp. via Magnetic Beads-based Fluorescent Lateral Flow Immunoassay*

Abstract

Polymerase chain reaction (PCR) plays an increasingly important role in microbial detection. However, the existing methods are difficult to be widely applied due to factors such as instruments, reagents, and experimental conditions. In this study, we developed a robust and reliable fluorescent lateral flow immunoassay combined with polymerase chain reaction (PCR-LFIA) based on magnetic beads purification for rapid detection of Salmonella app. The PCR-LFIA assay can avoid false positives caused by primer dimers. The sensitivity of PCR-LFIA method was 6×100 CFU/mL of Salmonella pure culture or 6×102 CFU/mL of artificially spiked chicken faeces. The specificity of PCR-LFIA assay was verified by eighteen Salmonella and non-Salmonella reference strains. Six of the eighty-five (7.1%) samples collected were positive by PCR-LFIA assay and the results were further confirmed by biochemical characteristics. This assay allows quantitative detection of Salmonella with a cutoff value of 175 and can be completed in 80 minutes. In conclusion, the optimized PCR-LFIA method can potentially serve as an effective diagnostic tool for timely response to disease outbreaks.