Comparison of the Diatheva STEC FLUO with BAX System Kits for Detection of O157:H7 and Non-O157 Shiga Toxin-Producing Escherichia coli (STEC) in Ground Beef and Bean Sprout Samples Using Different Enrichment Protocols

The aim of this study was to assess the performance of the Diatheva STEC FLUO and BAX System real-time PCR assays for detection of Shiga toxin-producing Escherichia coli (STEC) (stx1/stx2 and eae target genes) and O-group identification in ground beef and bean sprout samples. Ground beef (325 g or 25 g) and mung bean sprout (25 g) samples were inoculated with ~ 10 CFU of the Btop five^ STEC (O157:H7, O26, O103, O111, and O145 as specified in EU regulation ISO13136:2012), enriched using different broths and incubation temperatures, and tested using the Diatheva and BAX real-time PCR assays. In ground beef, both molecular methods were able to detect the Btop five^ STEC, and lower Ct values were observed for the Diatheva kits compared to BAX System. The O111-contaminated samples gave negative results with both methods using mTSB + novobiocin for enrichment. In bean sprouts, both methods provided positive results, although detection was not possible using mTSB + acriflavin/ cefsulodin/vancomycin for enrichment. In conclusion, the Diatheva and BAX methods detected the Btop five^ STEC in ground beef and bean sprouts when inoculated at low levels. Both assays provided equivalent results in terms of performance and reliability. Thus, the Diatheva kits are comparable to reference STEC-detection methods and could be used by the food industry to reliably detect the Btop five^ STEC.