GENESIS OF THE NOVEL EPIDEMIC VIBRIO-CHOLERAE-0139 STRAIN - EVIDENCE FOR HORIZONTAL TRANSFER OF GENES INVOLVED IN POLYSACCHARIDE SYNTHESIS
GENESIS OF THE NOVEL EPIDEMIC VIBRIO-CHOLERAE-0139 STRAIN - EVIDENCE FOR HORIZONTAL TRANSFER OF GENES INVOLVED IN POLYSACCHARIDE SYNTHESIS
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DOI：
10.1002/j.1460-2075.1995.tb06993.x
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发表时间：
1995-01-16
期刊：
影响因子：
11.4
通讯作者：
MOOI, FR
中科院分区：
文献类型：
--
作者：
BIK, EM;BUNSCHOTEN, AE;MOOI, FR
已知只有 O1 血清型霍乱弧菌菌株会引起流行，而非 O1 菌株则与零星霍乱病例有关。因此，出人意料的是，最近在亚洲爆发的霍乱疫情是由血清型为 O139 的非 O1 菌株引起的。我们提供的证据表明，O139 源自与当前霍乱大流行的病原体 V.cholerae O1 El Tor 密切相关的菌株，通过获得新的 DNA，该 DNA 插入并替换了受体菌株的部分 O 抗原基因簇。对部分新DNA进行了测序，观察到两个开放阅读框（otnA和otnB），其产物分别与参与荚膜和O抗原合成的蛋白质表现出同源性。这表明 otnAB DNA 决定了 O139 细胞表面的独特抗原特性。 O1 菌株中未检测到 otnAB DNA，但存在于血清型 O69 和 O141 的两种非 O1 霍乱弧菌菌株中。在 O69 和 O139 菌株中，otnAB 基因位于推定插入序列 (IS) 元件 rfbQRS 附近，该元件与 O1 菌株中的 O 抗原合成基因相关，并且可能在 otnAB DNA 插入受体染色体中发挥了作用。我们的结果表明，O139 菌株是由非 O1 菌株和 O1 菌株之间的水平基因转移产生的。获得的 DNA 改变了受体 O1 菌株的抗原特性，在大部分人群对 O1 菌株免疫的地区提供了选择性优势。这一基因事件可能导致了目前亚洲霍乱的流行。
Only Vibrio cholerae strains of serotype O1 are known to cause epidemics, while non-O1 strains are associated with sporadic cases of cholera. It was therefore unexpected that the recent cholera epidemic in Asia was caused by a non-O1 strain with the serotype O139. We provide evidence that O139 arose from a strain closely related to the causative agent of the present cholera pandemic, V.cholerae O1 El Tor, by acquisition of novel DNA which was inserted into, and replaced part of, the O antigen gene cluster of the recipient strain. Part of the novel DNA was sequenced and two open reading frames (otnA and otnB) were observed, the products of which showed hamology to proteins involved in capsule and O antigen synthesis, respectively. This suggests that the otnAB DNA determines the distinct antigenic properties of the O139 cell surface. The otnAB DNA was not detected in O1 strains, but was present in two non-O1 V.cholerae strains with serotypes O69 and O141. In the O69 and O139 strains the otnAB genes were located proximate to the putative insertion sequence (IS) element rfbQRS, which is associated with O antigen synthesis genes in O1 strains, and may have played a role in the insertion of the otnAB DNA in the recipient chromosome. Our results suggest that the O139 strain arose by horizontal gene transfer between a non-O1 and an O1 strain. The acquired DNA has altered the antigenic properties of the recipient O1 strain, providing a selective advantage in a region where a large part of the population is immune to O1 strains. This genetic event may have contributed to the present cholera epidemic in Asia.