舟山海岛鼠伤寒沙门菌肠毒素基因序列特征分析

Analysis of enterotoxin gene sequence characteristics of Salmonella typhimurium in Zhoushan

目的通过对6株鼠伤寒沙门菌肠毒素基因的进化特征分析,为舟山鼠伤寒沙门菌引起的食源性疾病防控提供理论依据。方法收集定海、普陀两区的鼠伤寒沙门菌6株,用PCR方法检测肠毒素基因并对阳性产物进行测序,通过DNA star软件对序列进行比对,构建基因进化树及序列。结果 6株鼠伤寒沙门菌肠毒素基因检测结果均为阳性,基因序列比对结果显示6株鼠伤寒沙门菌肠毒素基因的同源性为100.0%,与印度鼠伤寒沙门菌A201菌株（KF032246）和美国鼠伤寒沙门菌Q1菌株（L16014）的肠毒素基因序列的同源性为99.2%和100.0%;与柠檬酸杆菌肠毒素的同源性为85.3%-88.4%;与其他致病菌同类基因的同源性分别为26.6%-45.0%。结论近年来在舟山市流行的鼠伤寒沙门菌的肠毒素基因序列进化高度保守,与志贺菌、大肠埃希菌、霍乱弧菌、副溶血性弧菌及金黄色葡萄球菌的同类基因同源性较低,但与柠檬酸杆菌的肠毒素基因有较高的同源性应引起相关部门重视。

Objective To analyze the evolution characteristics of enterotoxin gene of 6 Salmonella typhimurium strains,so as to provide theoretic basis for the prevention of food born diseases caused by Salmonella typhimurium. Methods The enterotoxin genes of 6 Salmonella typhimurium collected from Dinghai district and Putuo district were amplified by PCR,and the positive products were sequenced. DNA star software was used for the sequences comparison,gene- based phylogenetic tree and building the sequence. Results The enterotoxin genes were all positive in 6 isolates and the sequence detection showed the homology was 100. 0%. The homologies of nucleotide were 99. 2%,100. 0% to A201（ KF032246） in India and Q1（ L16014） in America respectively. The sequence had similarity of 85. 3%- 88. 4% and 26. 6%- 45. 0% to Citrobacter freudii and the same kind genes in other pathogens. Conclusion The enterotoxin gene sequence evolution of Salmonella typhimurium epidemic in Zhoushan was highly conserved. It had a low similarity to Shigella,Escherichia coli,Vibrio cholera,Vibrio parahaemolyticus,Staphylococcus aureus except for Citrobacter freudii,which should be paid attention to.