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  • Phylogenetic and toxinogeni...
    Frentzel, Hendrik; Kraushaar, Britta; Krause, Gladys; Bodi, Dorina; Wichmann-Schauer, Heidi; Appel, Bernd; Mader, Anneluise

    Food control, January 2018, 2018-01-00, Letnik: 83
    Journal Article

    The foodborne pathogen Bacillus (B.) cereus is a common contaminant in spices and herbs. To further characterise B. cereus and its closely related group members present in spices and herbs, we analysed presumptive B. cereus strains isolated from six different condiments with view to B. cereus group species, phylogenetic affiliation and toxinogenic potential. Of a total of 59 isolates 44 were identified as B. cereus sensu stricto (s.s.), four as B. toyonensis-like, five as B. thuringiensis, one as B. weihenstephanensis, two as B. pseudomycoides/B. mycoides and three as undefined B. cereus group species. A maximum of three different species occurred simultaneously in the same spice sample. The isolates comprised 33 multilocus (ML) sequence types (STs), which can be assigned to three different phylogenetic groups. Except two B. pseudomycoides/B. mycoides strains, all isolates were able to produce enterotoxins and one strain the emetic toxin cereulide as detected by an immunoassay and LC-MS, respectively. The prevalence of toxin genes was 96.6% for nheA, 94.9% for hblD, 50.8% for cytK-2 and 1.7% for ces. The emetic strain was characterised by ST 869, which for the first time was assigned to an emetic B. cereus (s.s.) strain and is not part of the previously known two emetic MLST clusters. Our results demonstrate that not only B. cereus (s.s.) but also toxin producing B. thuringiensis, B. weihenstephanensis and B. toyonensis-like strains could be detected in condiments. For some isolates MLST revealed disagreements between phylogenetic relationship and the classification as B. weihenstephanensis and B. mycoides based on previously described species markers. •Different B. cereus group species occur simultaneously in condiments.•Prevalence of toxin genes was 96.6% nheA, 94.9% hblD, 50.8% cytK-2 and 1.7% ces.•ST 869 was for the first time assigned to an emetic B. cereus (s.s.) strain.•MLST revealed disagreements between phylogenetic relationships and species markers.