Centre for Immunology and Infection Control, Queensland University of Technology, Brisbane, Queensland, Australia.
Public Health Microbiology, Forensic and Scientific Services, Queensland Department of Health, Brisbane, Queensland, Australia.
Microbiol Spectr. 2023 Feb 14;11(1):e0263122. doi: 10.1128/spectrum.02631-22. Epub 2023 Jan 23.
Cholera caused by pathogenic Vibrio cholerae is still considered one of the major health problems in developing countries including those in Asia and Africa. Australia is known to have unique V. cholerae strains in Queensland waterways, resulting in sporadic cholera-like disease being reported in Queensland each year. We conducted virulence and antimicrobial genetic characterization of O1 and non-O1, non-O139 V. cholerae (NOVC) strains (1983 to 2020) from Queensland with clinical significance and compared these to environmental strains that were collected as part of a V. cholerae monitoring project in 2012 of Queensland waterways. In this study, 87 V. cholerae strains were analyzed where O1 ( = 5) and NOVC ( = 54) strains from Queensland and international travel-associated NOVC ( = 2) (61 in total) strains were sequenced, characterized, and compared with seven previously sequenced O1 strains and 18 other publicly available NOVC strains from Australia and overseas to visualize the genetic context among them. Of the 61 strains, three clinical and environmental NOVC serogroup strains had cholera toxin-producing genes, namely, the CTX phage (identified in previous outbreaks) and the complete pathogenicity island 1. Phylogenetic analysis based on core genome analysis showed more than 10 distinct clusters and interrelatedness between clinical and environmental V. cholerae strains from Australia. Moreover, 30 (55%) NOVC strains had the cholix toxin gene () while only 11 (20%) strains had the gene. In addition, 18 (34%) NOVC strains from Australia had the type three secretion system and discrete expression of type six secretion system genes. Interestingly, four NOVC strains from Australia and one NOVC strain from Indonesia had SXT, a mobile genetic element. Several strains were found to have beta-lactamase () and chloramphenicol acetyltransferase () genes. Our study suggests that Queensland waterways can harbor highly divergent V. cholerae strains and serve as a reservoir for various V. cholerae-associated virulence genes which could be shared among O1 and NOVC V. cholerae strains via mobile genetic elements or horizontal gene transfer. Australia has its own V. cholerae strains, both toxigenic and nontoxigenic, that are associated with cholera disease. This study aimed to characterize a collection of clinical and environmental NOVC strains from Australia to understand their virulence and antimicrobial resistance profile and to place strains from Australia in the genetic context of international strains. The findings from this study suggest the toxigenic V. cholerae strains in the Queensland River water system are of public health concern. Therefore, ongoing monitoring and genomic characterization of V. cholerae strains from the Queensland environment are important and would assist public health departments to track the source of cholera infection early and implement prevention strategies for future outbreaks. Understanding the genomics of V. cholerae could also inform the natural ecology and evolution of this bacterium in natural environments.
由致病性霍乱弧菌引起的霍乱仍然被认为是包括亚洲和非洲在内的发展中国家的主要卫生问题之一。众所周知,澳大利亚昆士兰州的水道中存在独特的霍乱弧菌菌株,导致每年昆士兰州都会报告散发性霍乱样疾病。我们对具有临床意义的来自昆士兰州的 O1 和非 O1、非 O139 霍乱弧菌 (NOVC) 菌株(1983 年至 2020 年)进行了毒力和抗菌遗传特征分析,并将这些菌株与作为 2012 年昆士兰州水道霍乱弧菌监测项目一部分收集的环境菌株进行了比较。在这项研究中,分析了 87 株霍乱弧菌菌株,其中 O1(=5)和 NOVC(=54)菌株来自昆士兰州和国际旅行相关的 NOVC(=2)(共 61 株)菌株进行了测序、特征分析,并与之前测序的 7 株 O1 菌株和来自澳大利亚和海外的 18 株其他公开的 NOVC 菌株进行了比较,以可视化它们之间的遗传背景。在 61 株菌株中,3 株临床和环境 NOVC 血清群菌株具有霍乱毒素产生基因,即 CTX 噬菌体(在前几次暴发中鉴定出)和完整的致病性岛 1。基于核心基因组分析的系统发育分析显示,来自澳大利亚的临床和环境霍乱弧菌菌株之间存在 10 多个不同的簇和相关性。此外,30 株(55%)NOVC 菌株具有 cholix 毒素基因(),而只有 11 株(20%)菌株具有 基因。此外,来自澳大利亚的 18 株(34%)NOVC 菌株具有 III 型分泌系统和离散的 VI 型分泌系统基因表达。有趣的是,来自澳大利亚的 4 株 NOVC 菌株和来自印度尼西亚的 1 株 NOVC 菌株具有 SXT,这是一种移动遗传元件。一些菌株被发现具有β-内酰胺酶()和氯霉素乙酰转移酶()基因。我们的研究表明,昆士兰州的水道可以容纳高度分化的霍乱弧菌菌株,并作为各种霍乱弧菌相关毒力基因的储库,这些基因可以通过移动遗传元件或水平基因转移在 O1 和 NOVC 霍乱弧菌菌株之间共享。澳大利亚拥有与霍乱疾病相关的毒力和非毒力霍乱弧菌菌株。本研究旨在对来自澳大利亚的临床和环境 NOVC 菌株进行特征分析,以了解它们的毒力和抗菌药物耐药谱,并将来自澳大利亚的菌株置于国际菌株的遗传背景下。这项研究的结果表明,昆士兰州河流系统中的毒力型霍乱弧菌菌株对公共卫生构成威胁。因此,对昆士兰州环境中霍乱弧菌菌株进行持续监测和基因组特征分析非常重要,这将有助于公共卫生部门尽早追踪霍乱感染源,并为未来的暴发实施预防策略。了解霍乱弧菌的基因组学还可以为该细菌在自然环境中的自然生态和进化提供信息。