Growth and verocytotoxin productivity of Escherichia coli O157 grown at low temperature in foods

我们研究了食品中低温培养的大肠杆菌O157的生长和产胞毒素的情况。从人、牛和食品中分离到大肠杆菌菌株，分析了它们的基因组图谱和产生的蠕形细胞毒素类型。我们使用了几种不同的菌株，它们产生的维细胞毒素的基因组图谱和类型都不同。在4℃以下，E.ColiO157的生长速度很低，但随着温度的升高而增加。在8℃时，生长速度随蔬菜类型的不同而变化。O157大肠杆菌在黄瓜和生姜上生长良好，但在青椒上略有生长。当牛肉和牛奶接种O157大肠杆菌时，细胞在牛肉上生长良好。用牛乳培养时，发现O157和非致病性大肠杆菌的生长速度不同：O157的生长速度高于非致病性大肠杆菌。根据细胞生长的菌株和食物类型的不同，卵胞毒素的产量也会发生变化。

We examined the growth and verocytotoxin productivity of Escherichia coli O157 grown at low temperature in foods. E.coli strains were isolated from human, bovine and foods, and their genomic profiles and the types of verocytotoxin they produced were analyzed. We used several strains different in the genomic profiles and types of verocytotoxin they produced. The growth rate of E.coli O157 was very low below 4℃, but increased with increase of the temperature. At 8℃, the growth rate changed depending on the types of vegetables. E.coli O157 well grew on cucumber and ginger, but slightly grew on green pepper. When beef and cow's milk were inoculated with E.coli O157, the cells well grew on beef. Difference between E.coli O157 and non-pathogenic E.coli was observed when we used cow's milk : E.coli O157 showed higher growth rate than non-pathogenic E.coli. The verocytotoxin productivity was found to change depending on the strains and types of foods in which the cells grew.