Rapid detection of viable Bacillus cereus emetic and enterotoxic strains in food by coupling propidium monoazide and multiplex PCR (PMA-mPCR). (September 2015)

• Record Type: Journal Article
• Authors: Forghani, Fereidoun; Langaee, Taimour; Eskandari, Mohammad; Seo, Kun-Ho; Chung, Mi-Ja; Oh, Deog-Hwan
• Is Part Of: Food control. Volume 55(2015:Sep.)
• Page Start: 151
• Page End: 157
• Publication Date: 2015-09
• Subjects: Bacillus cereus -- Propidium monoazide (PMA) -- Multiplex PCR -- Emetic toxin -- Enterotoxin -- Food; Food -- Quality -- Periodicals; Food -- Analysis -- Periodicals; Food handling -- Periodicals; Food industry and trade -- Quality control -- Periodicals; Aliments -- Industrie et commerce -- Qualité -- Contrôle -- Périodiques; Aliments -- Qualité -- Périodiques; Aliments -- Analyse -- Périodiques; Hygiène alimentaire -- Périodiques; Food -- Analysis; Food handling; Food -- Quality; Periodicals; Electronic journals; 664.07
• DOI: 10.1016/j.foodcont.2015.02.049
• Languages: English
• ISSNs: 0956-7135

Abstract

Abstract: Bacillus cereus can cause emetic and diarrheal food poisoning. It is widespread in nature and therefore, considered a major foodborne pathogen. To develop a sensitive and reliable assay for detecting enterotoxin genes ( nheA, entFM, hblD, cytK ) and emetic toxin ( ces ), specific primers each targeting one individual gene were designed. Propidium monoazide (PMA) was coupled with the developed multiplex PCR (mPCR) for the detection of viable B. cereus. The inclusivity and exclusivity of the PMA-mPCR was confirmed using a panel of 44 strains including 17 emetic and 9 enterotoxic B. cereus reference strains and 18 non-target strains. The limit of detection (LOD) without PMA treatment in pure DNA was 2 pg/reaction tube. The LOD of mPCR assay in pure heat-killed dead bacteria was 4.0 × 10 2 CFU/mL. Also, the LOD on the viable bacteria with or without PMA treatment was similar (3.8 × 10 2 CFU/mL) showing that the PMA treatment did not significantly decrease sensitivity. Finally, the newly developed PMA-mPCR successfully detected 4.8 × 10 3 and 3.6 × 10 3 CFU/g of viable B. cereus F4810/72 (emetic) and B. cereus ATCC 12480 (enterotoxic) reference strains, respectively, in food samples. Hence, this study combines PMA and mPCR to detect viable B. cereus with a wide range of toxin detection (5 toxins). Thus, the novel PMA-mPCR assay developed in this study is a rapid and efficient diagnostic tool for the monitoring of viable B. cereus in food samples and potentially other samples via appropriate DNA extraction. Highlights: First paper to report the detection of viable Bacillus cereus with emetic/enterotoxic differentiation. Having same limit of detection with previous approaches without viable cell detection. Having the widest toxin detection range among similar approaches. Suitable for toxigenic profiling of food or clinical samples by only viable cells.