Iwasa M, Makino S, Asakura H, Kobori H, Morimoto Y
Laboratory of Entomology, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido, Japan.
J Med Entomol. 1999 Jan;36(1):108-12. doi: 10.1093/jmedent/36.1.108.
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 was isolated for the first time from Musca domestica L. A total of 310 fly samples was collected from 4 different farms in Obihiro-City, Hokkaido, in the summer and autumn of 1997;5 samples carried E. coli serotype O157:H7. Using ELISA and Vero cell cytotoxicity assay, 3 isolates from 1 cattle farm produced both active Shiga-toxin type 1 (Stx1) and 2 (Stx2). These isolates also carried hemolysin and eaeA genes and harbored the 90-kb virulence plasmid of EHEC O157:H7. Based on plasmid profiles, antibiotic patterns, polymerase chain reaction (PCR)-based DNA finger printing analysis using random amplified polymorphic DNA, pulsed field gel electrophoresis analysis, and DNA sequences of stx1 and stx2, all 3 isolates from fly samples were identical. These results indicate that the house fly is capable of carrying the toxigenic EHEC O157:H7 involved in human disease.
首次从家蝇中分离出肠出血性大肠杆菌（EHEC）O157:H7。1997年夏秋季节，从北海道带广市的4个不同农场共采集了310份苍蝇样本；其中5份样本携带大肠杆菌O157:H7血清型。使用酶联免疫吸附测定（ELISA）和Vero细胞细胞毒性试验，从1个养牛场分离出的3株菌株均产生了活性志贺毒素1型（Stx1）和2型（Stx2）。这些分离株还携带溶血素和eaeA基因，并含有EHEC O157:H7的90kb毒力质粒。基于质粒图谱、抗生素谱、使用随机扩增多态性DNA的聚合酶链反应（PCR）DNA指纹分析、脉冲场凝胶电泳分析以及stx1和stx2的DNA序列，来自苍蝇样本的所有3株分离株均相同。这些结果表明，家蝇能够携带与人类疾病相关的产毒EHEC O157:H7。
