| Abstrakt: |
Bacillus cytotoxicus,a member of the Bacillus cereusgroup, is a thermotolerant species originally reported from a lethal foodborne infection in France in 1998. The strain NVH391-98, isolated from this outbreak, produces cytotoxin K1, a potential cytotoxic enterotoxin. However, the habitat and diversity of B. cytotoxicusisolates so far have been poorly explored. The objective of this study was to assess the prevalence of this bacterium in different food products (mainly dried) and to estimate its diversity. Among the 210 samples analyzed, all potato flakes contained the bacterium at low concentrations (≤102CFU/g). However, prepared and kept at room temperature for 2 days, the puree contained ca. 105CFU/g B. cytotoxicus. Besides potato flakes, some samples of millet flour, salted potato chips, and soups also contained B. cytotoxicus. From these samples, 55 thermotolerant B. cytotoxicusisolates were obtained. When classified into six distinct random amplified polymorphism DNA patterns, they showed the existence of 11 distinct plasmid profiles. Although most isolates (including the reference strains NVH391-98 and NVH883-00) contained no detectable plasmid, some displayed one to three plasmids with sizes from ca. 8 to 90 kb. It also emerged from this study that a single food sample could contain B. cytotoxicusisolates with different genetic profiles. |
