Department of Public Health, Comparative Pathology and Veterinary Hygiene, University of Padova, Agripolis, Viale dell'Università 16, 35020 Legnaro, Padua, Italy.
Appl Environ Microbiol. 2011 Jul;77(14):4986-5000. doi: 10.1128/AEM.00708-11. Epub 2011 Jun 3.
The genus Aeromonas has been described as comprising several species associated with the aquatic environment, which represents their principal reservoir. Aeromonas spp. are commonly isolated from diseased and healthy fish, but the involvement of such bacteria in human infection and gastroenteritis has frequently been reported. The primary challenge in establishing an unequivocal link between the Aeromonas genus and pathogenesis in humans is the extremely complicated taxonomy. With the aim of clarifying taxonomic relationships among the strains and phenotypes, a multilocus sequencing approach was developed and applied to characterize 23 type and reference strains of Aeromonas spp. and a collection of 77 field strains isolated from fish, crustaceans, and mollusks. All strains were also screened for putative determinants of virulence by PCR (ast, ahh1, act, asa1, eno, ascV, and aexT) and the production of acylated homoserine lactones (AHLs). In addition, the phenotypic fingerprinting obtained from 29 biochemical tests was submitted to the nonparametric combination (NPC) test methodology to define the statistical differences among the identified genetic clusters. Multilocus sequence typing (MLST) achieved precise strain genotyping, and the phylogenetic analysis of concatenated sequences delineated the relationship among the taxa belonging to the genus Aeromonas, providing a powerful tool for outbreak traceability, host range diffusion, and ecological studies. The NPC test showed the feasibility of phenotypic differentiation among the majority of the MLST clusters by using a selection of tests or the entire biochemical fingerprinting. A Web-based MLST sequence database (http://pubmlst.org/aeromonas) specific for the Aeromonas genus was developed and implemented with all the results.
气单胞菌属被描述为由几种与水生环境相关的物种组成，水生环境是其主要的宿主。气单胞菌属通常从患病和健康的鱼类中分离出来，但这些细菌与人类感染和肠胃炎的关系经常被报道。在确定气单胞菌属与人类发病机制之间明确联系的主要挑战是极其复杂的分类学。为了澄清菌株和表型之间的分类关系，开发了一种多位点测序方法，并应用于描述 23 种气单胞菌属的参考株和从鱼类、甲壳类动物和软体动物中分离的 77 株田间株。所有菌株还通过 PCR（ast、ahh1、act、asa1、eno、ascV 和 aexT）和酰化高丝氨酸内酯（AHLs）的产生筛选潜在的毒力决定因素。此外，从 29 种生化试验获得的表型指纹图谱被提交给非参数组合（NPC）试验方法，以定义鉴定的遗传聚类之间的统计差异。多位点序列分型（MLST）实现了精确的菌株基因分型，串联序列的系统发育分析描绘了气单胞菌属中分类群之间的关系，为暴发溯源、宿主范围扩散和生态研究提供了有力的工具。NPC 试验表明，通过选择测试或整个生化指纹图谱，大多数 MLST 聚类之间可以进行表型分化。开发了一个针对气单胞菌属的基于网络的 MLST 序列数据库（http://pubmlst.org/aeromonas），并实现了所有结果。
