Milk-originated Bacillus cereus sensu lato strains harbouring Bacillus anthracis-like plasmids are genetically and phenotypically diverse
Milk-originated Bacillus cereus sensu lato strains harbouring Bacillus anthracis-like plasmids are genetically and phenotypically diverse
复制标题
DOI：
10.1016/j.fm.2017.05.009
复制
发表时间：
2017-10-01
影响因子：
5.3
通讯作者：
Marjanska, Paulina Sylwia
中科院分区：
文献类型：
--
作者：
Bartoszewicz, Marek;Marjanska, Paulina Sylwia
广义蜡状芽孢杆菌广泛分布于食品中，包括生奶和加工奶。质粒酶通常决定细菌的毒力和毒性，但它们在B进化中的作用。广义蜡状病毒只是部分已知。在这里，我们观察到，近8%的B.在来自一家乳制品工厂的生奶和超热处理（UHT）奶中，蜡状酵母分离株对pXO 1样质粒呈阳性，对pXO 2样质粒呈阳性的比例为12%。然而，pXO1样质粒显着更频繁的原料奶，而pXO2样质粒更频繁的加工牛奶。来自生牛奶和UHT牛奶的菌株是肠致病性的，多达五分之一的菌株是耐冷的。采用多位点序列分型的系统发育评估揭示了这些杆菌的多系结构，具有不同的冷适应分离株和致病菌株组（包括呕吐B。cereus）。两个采样点对应的种群表现出显着的连锁不平衡和纯化选择的存在。远离克隆的种群结构表明存在适应乳制品行业特定条件的序列类型或生态型。高的重组突变率表明B之间的水平基因转移起着重要作用。牛奶中分离出广义蜡状芽孢杆菌。(C)2017爱思唯尔有限公司版权所有
Bacillus cereus sensu lato is widely distributed in food products, including raw and processed milk. Plasmids often determine bacterial virulence and toxicity, but their role in the evolution of B. cereus sensu lato is only partly known. Here, we observed that nearly 8% of B. cereus sensu lato isolates were positive for pXO1-like plasmids and 12% for pXO2-like plasmids in raw and ultra-heat-treated (UHT) milk from one dairy plant. However, pXO1-like plasmids were significantly more frequent in raw milk, while pXO2-like plasmids were more frequent in processed milk. Strains from raw and UHT milk were enterotoxigenic, with up to one-fifth of the isolates being psychrotolerant. Phylogenetic assessment using multi locus sequence typing revealed a polyphyletic structure for these bacilli, with distinct groups of cold adapted isolates and pathogenic strains (including emetic B. cereus). Populations corresponding to both sampling sites exhibited significant linkage disequilibrium and the presence of purifying selection. The far-from-clonal population structure indicated the presence of sequence types or ecotypes adapted to specific conditions in the dairy industry. A high recombination-to-mutation ratio suggested an important role for horizontal gene transfer among B. cereus sensu lato isolates in milk. (C) 2017 Elsevier Ltd. All rights reserved.