Marine Biology Research Division and Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego, 8750 Biological Grade, La Jolla, CA 92093-0202, USA. Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), km. 107 Carr, Tijuana-Ensenada, 22860 B.C. México. International Center for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh. Instituto de Acuicultura, Universidad de Santiago de Compostela, Santiago de Compostela, Spain. Maryland Pathogen Research Institute and 7Center for Bioinformatics and Computational Biology, University of Maryland, College Park, MD 20742, USA.
Environ Microbiol Rep. 2010 Feb;2(1):198-207. doi: 10.1111/j.1758-2229.2010.00139.x.
Non-toxigenic non-O1, non-O139 Vibrio cholerae strains isolated from both environmental and clinical settings carry a suite of virulence factors aside from cholera toxin. Among V. cholerae strains isolated from coastal waters of southern California, this includes cholix toxin, an ADP-ribosylating factor that is capable of halting protein synthesis in eukaryotic cells. The prevalence of the gene encoding cholix toxin, chxA, was assessed among a collection of 155 diverse V. cholerae strains originating from both clinical and environmental settings in Bangladesh and Mexico and other countries around the globe. The chxA gene was present in 47% of 83 non-O1, non-O139 strains and 16% of 72 O1/O139 strains screened as part of this study. A total of 86 chxA gene sequences were obtained, and phylogenetic analysis revealed that they fall into two distinct clades. These two clades were also observed in the phylogenies of several housekeeping genes, suggesting that the divergence observed in chxA extends to other regions of the V. cholerae genome, and most likely has arisen from vertical descent rather than horizontal transfer. Our results clearly indicate that ChxA is a major toxin of V. cholerae with a worldwide distribution that is preferentially associated with non-pandemic strains.
从环境和临床环境中分离出的非产毒非 O1、非 O139 霍乱弧菌株除霍乱毒素外，还携带一系列毒力因子。在从加利福尼亚州南部沿海水域分离出的霍乱弧菌株中，这包括霍乱毒素，一种能够阻止真核细胞中蛋白质合成的 ADP-核糖基化因子。本研究评估了编码霍乱毒素 chxA 的基因在来自孟加拉国和墨西哥以及全球其他国家的临床和环境来源的 155 种不同霍乱弧菌株中的流行情况。chxA 基因存在于本研究筛选的 83 株非 O1、非 O139 菌株中的 47%和 72 株 O1/O139 菌株中的 16%。共获得了 86 个 chxA 基因序列，系统发育分析表明它们分为两个不同的分支。这两个分支也存在于几个管家基因的系统发育中，这表明 chxA 中的分化延伸到霍乱弧菌基因组的其他区域，并且很可能是垂直进化而不是水平转移的结果。我们的研究结果清楚地表明，ChxA 是一种具有全球分布的霍乱弧菌主要毒素，它与非流行菌株密切相关。
