Dual-Gene Based Recombinase-Aided Amplification (RAA) - Lateral Flow Strip for the Sensitive On-Site Detection of Yersinia enterocolitica in Food Samples

BACKGROUND: Yersinia enterocolitica is one of the most common foodborne pathogens worldwide. Currently, most detection methods are primarily focused on pathogenic strains of Y. enterocolitica; while it has been frequently observed that traditionally believed "non-pathogenic" strains of Y. enterocolitica can also cause human disease. OBJECTIVE: Herein, we have developed a novel dual-recombinase-aided amplification (RAA)-lateral flow test strip assay targeting both of a pathogenic marker (ail) and a conserved gene (foxA) for the rapid detection of both pathogenic and non-pathogen Y. enterocolitica strains in food samples. METHODS: Primers and probes were designed and optimized for the detection of ail and foxA genes using RAA technology. The optimal RAA-LFS assay was then evaluated for specificity and sensitivity, and validated in both chicken samples spiked with a series of ten-fold diluted Y. enterocolitica cultures and 100 natural food samples including milk, chicken, beef, pork, and salmon. RESULTS: The newly designed assay demonstrated 100% specificity and achieved a detection limit of 17 CFU/reaction for both targets, with the entire sample preparation and detection process completed within 25 min. Additionally, the assay showed high sensitivity in spiked chicken samples, achieving a detection limit of 1.03 × 10-1 CFU/mL for both targets. Validation with the natural food samples confirmed the robustness of the assay, as the results from this new assay were in agreement with those from the commonly used traditional techniques. CONCLUSIONS: In summary, the dual RAA-LFS assay integrates two genetic markers into a single test strip, providing a rapid, cost-effective, specific, and sensitive tool for on-site detection of pathogenic and common Y. enterocolitica strains. HIGHLIGHTS: A novel dual RAA-LFS assay for the rapid detection of both pathogenic and common Y. enterocolitica strains was developed.