Evolutionary genetic analysis of the emergence of epidemic Vibrio cholerae isolates on the basis of comparative nucleotide sequence analysis and multilocus virulence gene profiles
Evolutionary genetic analysis of the emergence of epidemic Vibrio cholerae isolates on the basis of comparative nucleotide sequence analysis and multilocus virulence gene profiles
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DOI：
10.1128/jcm.42.10.4657-4671.2004
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发表时间：
2004-10-01
影响因子：
9.4
通讯作者：
Boyd, EF
中科院分区：
文献类型：
--
作者：
O'Shea, YA;Reen, FJ;Boyd, EF
霍乱弧菌是霍乱的病原体，是水生生态系统的自然居民。我们研究了一个独特的收集霍乱弧菌临床和环境菌株的广泛的地理分布恢复了60年的时间，以确定其进化的遗传关系的基础上分析的两个管家基因，苹果酸脱氢酶（mdh）和伴侣蛋白（groEL）。此外，12个与毒力相关的区域的系统发育分布进行了确定。mdh序列比较分析表明，O1和O139群霍乱弧菌分离株属于同一克隆谱系。在groEL这些O1和O139菌株的单链构象多态性（SSCP）分析证实了流行性克隆复合物的存在。在检测的12个毒力区域中，只有三个区域，即第七次大流行岛1（Vibrio seventh pandemic island 1，VSP-I）、VSP-II和RS1，在所有经典霍乱弧菌分离株中均不存在。大多数霍乱弧菌El Tor生物型和O139血清型分离株，只有一株VO7含有VSP-I。两个霍乱弧菌El Tor分离株，GP 155和2164 - 78，缺乏VSP-I和VSP-II，一个El Tor分离株，GP 43，缺乏VSP-II。5株非O1/非O139血清群分离株的mdh序列与流行株O1和O139的mdh序列相同。这些分离株，类似于经典菌株，缺乏VSP-I和VSP-II。在所有分离株中发现了12个毒力区中的4个：hlyA、pilE、MSHA和RTX。然而，在非O1/非O139分离株中，另外8个区域的发生率相当低。霍乱弧菌自然分离株的进化关系和多位点毒力基因谱表明，连续的大流行毒株是通过连续获得新的毒力区域而从共同的O1血清群祖先产生的。
Vibrio cholerae, the causative agent of cholera, is a natural inhabitant of the aquatic ecosystem. We examined a unique collection of V. cholerae clinical and environmental isolates of widespread geographic distribution recovered over a 60-year period to determine their evolutionary genetic relationships based on analysis of two housekeeping genes, malate dehydrogenase (mdh) and a chaperonin (groEL). In addition, the phylogenetic distribution of 12 regions associated with virulence was determined. Comparative sequence analysis of mdh revealed that all V. cholerae O1 and O139 serogroup isolates belonged to the same clonal lineage. Single-strand conformational polymorphism (SSCP) analysis of these O1 and O139 strains at groEL confirmed the presence of an epidemic clonal complex. Of the 12 virulence regions examined, only three regions, Vibrio seventh pandemic island 1 (VSP-I), VSP-II, and RS1, were absent from all classical V. cholerae isolates. Most V. cholerae El Tor biotype and O139 serogroup isolates, only one strain, VO7, contained VSP-I. Two V. cholerae El Tor isolates, GP155 and 2164-78, lacked both VSP-I and VSP-II, and one El Tor isolate, GP43, lacked VSP-II. Five non-O1/non-O139 serogroup isolates had an mdh sequence identical to that of the epidemic O1 and O139 strains. These isolates, similar to classical strains, lack both VSP-I and VSP-II. Four of the 12 virulence regions examined were found to be present in all isolates: hlyA, pilE, MSHA and RTX. Among non-O1/non-O139 isolates, however, the occurrence of the additional eight regions was considerably lower. The evolutionary relationships and multilocus virulence gene profiles of V. cholerae natural isolates indicate that consecutive pandemic strains arose from a common O1 serogroup progenitor through the successive acquisition of new virulence regions.