新興霍亂弧菌O139型感染事件之分子流行病學分析   全文下載

Molecular Epidemiology of Newly Emerged V. cholerae O139 in Taiwan

1997年8月台灣高雄地區首次發現感染霍亂孤菌（Vibrio cholerae） O139型病例，經追查得知因生食甲魚卵而被感染，並從甲魚及甲魚池檢出霍亂孤菌O139 型；本菌近年來頗受國內外防疫界之重視。本研究收集當時分別從甲魚及甲魚池環境所分離出之霍亂孤菌O139型菌株共14株，及當時個案病例之1株臨床分離株共15株，以聚合?鏈反應法（PCR）測試其染色體上霍亂毒素基因cho1era toxin gene （ctxA和ctxB）和共同調控毒素纖毛基因toxin-coregulated pili gene （tcpA和tcpI）之普及率，發現14株環境和1株臨床本土性菌株對此四種基因均為陽性反應；以脈場膠電泳法（pulsed-field gel electrophoresis, PFGE）進行基因組分型比較，分別以限制酵素SfiI或NotI切割，15株菌株以限制酵素SfiI分為5次型，以限制酵素NotI分為3次型，臨床分離株與14株環境分離株之PFGE圖譜彼此間或相同或僅相差1~3個帶狀片段，經由SfiI分型其D系數（Dice coefficients）介於0.88 至1.0；經由NotI分型其D系數介於0.87至1.0。雖然以質體輪廓分析法（plasmid profile analysis）可將15株菌株區分為3型，臨床分離株與其中12株環境分離株質體輪廓分型圖譜相同。綜合以上分析結果，推論這些菌株衍生自相同菌源，即臨床分離株應源自環境分離株。顯示分子分型有利於霍亂感染案件分離株之追查印證。"

A Vibrio cholerae O139 strain was isolated from a cholera patient in August 1997 in Kaohsiung County, Taiwan. This was the first case of V. cholerae O139 emerging in Taiwan. An epidemiological study showed that the infectious source was turtle eggs. One clinical isolate and fourteen isolates from environmental specimens of the turtle farm were collected. From all isolates, the genes encoded for cholera toxin (ctxA and ctxB) and for toxin-coregulated pili genes (tcpA and tcpI) were specifically amplified by polymerase chain reactions. In pulsed-field gel electrophoresis (PFGE) studies, these isolates were categorized to five subtypes using SfiI restriction digestion; whereas three distinct subtypes were identified when NotI was used for digestion. The banding pattern of the clinical isolate in PFGE only differed by 1-3 bands from those of the environmental isolates regardless of the restriction enzyme used. The Dice coefficients were found to be in the range of 0.88-1.0 and 0.87-1.0, respectively, by using SfiI and NotI for the subtyping. When these isolates were analyzed by plasmid profile analysis, the profile pattern of the clinical strain was identical to 12 of the 14 environmental strains. Based on these results, it was concluded that the fifteen strains studied were descended from the same origin, with the clinical isolate originated from the environmental isolates. The data suggests that the molecular subtyping is a powerful tool for tracing and verifying the infectious sources of V. cholerae cases. 1997年8月台灣高雄地區首次發現感染霍亂孤菌（Vibrio cholerae） O139型病例，經追查得知因生食甲魚卵而被感染，並從甲魚及甲魚池檢出霍亂孤菌O139 型；本菌近年來頗受國內外防疫界之重視。本研究收集當時分別從甲魚及甲魚池環境所分離出之霍亂孤菌O139型菌株共14株，及當時個案病例之1株臨床分離株共15株，以聚合酶鏈反應法（PCR）測試其染色體上霍亂毒素基因cho1era toxin gene （ctxA和ctxB）和共同調控毒素纖毛基因toxin-coregulated pili gene （tcpA和tcpI）之普及率，發現14株環境和1株臨床本土性菌株對此四種基因均為陽性反應；以脈場膠電泳法（pulsed-field gel electrophoresis, PFGE）進行基因組分型比較，分別以限制酵素SfiI或NotI切割，15株菌株以限制酵素SfiI分為5次型，以限制酵素NotI分為3次型，臨床分離株與14株環境分離株之PFGE圖譜彼此間或相同或僅相差1～3個帶狀片段，經由SfiI分型其D系數（Dice coefficients）介於0.88 至1.0；經由NotI分型其D系數介於0.87至1.0。雖然以質體輪廓分析法（plasmid profile analysis）可將15株菌株區分為3型，臨床分離株與其中12株環境分離株質體輪廓分型圖譜相同。綜合以上分析結果，推論這些菌株衍生自相同菌源，即臨床分離株應源自環境分離株。顯示分子分型有利於霍亂感染案件分離株之追查印證。