Funamori Y, Fujinaga Y, Yokota K, Inoue K, Hirai Y, Oguma K, Kira S, Taketa K
Department of Public Health, Okayama University Medical School, Japan.
Acta Med Okayama. 1999 Aug;53(4):193-200. doi: 10.18926/AMO/31612.
Three outbreaks and many isolated cases of enterohemorrhagic Escherichia coli O157:H7 occurred in 1996 and 1997 in Okayama Prefecture, Japan. In an attempt to investigate the route of these infections, the strains isolated from the 3 outbreaks (total 33 strains) and 15 isolated cases (total 15 strains) were investigated using random amplification of polymorphic DNA (RAPD) and pulsed-field gel electrophoresis (PFGE). In addition, 10 strains from an outbreak in Tojo Cho, Hiroshima Prefecture (June 1996), 2 strains from the particular types of meat in Kochi Prefecture, and 42 strains isolated from bovine feces in a farm in Okayama Prefecture were also investigated in the same manner. PFGE was much more useful than RAPD for molecular typing of the clinical isolates, in that it allowed us to classify them into 10 PFGE groups. We noted that the strains differed according to the time and place of the outbreaks (or isolated cases). This indicates that O157:H7 infections in Okayama Prefecture were caused by different strains (although some cases were aggravated by the same strains as were found in other areas). The isolates from bovine feces were classified into 5 groups by PFGE profiles, but none of them were identical to those of the clinical isolates.
1996年和1997年，日本冈山县发生了3起肠出血性大肠杆菌O157:H7暴发疫情以及多起散发病例。为了调查这些感染的传播途径，我们运用随机扩增多态性DNA（RAPD）和脉冲场凝胶电泳（PFGE）技术，对从3起暴发疫情中分离出的菌株（共33株）以及15例散发病例中分离出的菌株（共15株）进行了研究。此外，还以同样的方式对来自广岛县东条町一起暴发疫情的10株菌株（1996年6月）、高知县特定类型肉类中的2株菌株以及冈山县一个农场牛粪便中分离出的42株菌株进行了研究。对于临床分离株的分子分型，PFGE比RAPD更为有效，它能使我们将这些菌株分为10个PFGE组。我们注意到，这些菌株因疫情暴发（或散发病例）的时间和地点不同而存在差异。这表明，冈山县的O157:H7感染是由不同菌株引起的（尽管有些病例是由与其他地区相同的菌株导致病情加重）。通过PFGE图谱，牛粪便中分离出的菌株被分为5组，但没有一组与临床分离株相同。
