Institute for Food Safety and Hygiene, Vetsuisse Faculty University of Zurich, Winterthurerstrasse 272, 8057 Zurich, Switzerland.
FEMS Microbiol Lett. 2019 Oct 1;366(20). doi: 10.1093/femsle/fnz240.
Data on the occurrence, population structure and toxinogenic potential of Bacillus cereus sensu lato isolated from flour is essential to enable improved risk assessment. We aimed to provide data on the occurrence of B. cereus sensu lato in flour products at retail level. In addition, we screened the isolates for Bacillus thuringiensis and Bacillus cytotoxicus and determined population structure and toxin gene profiles. We screened 89 flour products for presence of B. cereus sensu lato, resulting in 75 positive samples (84%). We were able to show that the population structure of members of the B. cereus group isolated from flour is highly diverse. Isolates were assigned to panC types II (4%), III (21%), IV (39%) and V (36%). Production of parasporal crystals characteristic for Bacillus thuringiensis was detected in seven isolates assigned to panC type III, IV and V. No B. cytotoxicus were detected. Two of the isolates harbored ces encoding cereulide, which causes the emetic syndrome. Various enterotoxin genes were found, with all isolates harboring nhe, 75% of isolates harboring hbl and 51% of the isolates harboring cytK-2. Our findings suggest that toxinogenic B. cereus sensu lato are common in flour products at retail level.
有关从面粉中分离出的蜡样芽胞杆菌属（Bacillus cereus sensu lato）的发生、种群结构和产毒潜能的数据对于改进风险评估至关重要。我们旨在提供零售级面粉产品中蜡样芽胞杆菌属（Bacillus cereus sensu lato）发生的数据。此外，我们筛选了这些分离株中是否存在苏云金芽孢杆菌（Bacillus thuringiensis）和细胞毒素芽孢杆菌（Bacillus cytotoxicus），并确定了种群结构和毒素基因谱。我们筛选了 89 种面粉产品中是否存在蜡样芽胞杆菌属（Bacillus cereus sensu lato），结果有 75 个阳性样品（84%）。我们能够表明，从面粉中分离出的蜡状芽孢杆菌群成员的种群结构非常多样化。分离株被分配到 panC 型 II（4%）、III（21%）、IV（39%）和 V（36%）。在被分配到 panC 型 III、IV 和 V 的 7 个分离株中检测到了特征性的苏云金芽孢杆菌的伴孢晶体。未检测到细胞毒素芽孢杆菌。其中两个分离株携带编码呕吐毒素的 ces 基因，这会导致呕吐综合征。发现了各种肠毒素基因，所有分离株均携带 nhe，75%的分离株携带 hbl，51%的分离株携带 cytK-2。我们的研究结果表明，产毒蜡样芽胞杆菌属（Bacillus cereus sensu lato）在零售级面粉产品中很常见。
