Investigation of the virulence of aeromonads recovered from human mixed infections, tested alone and in association in the Caenorhabditis elegans model.. Virulence of Aeromonas in the Caenorhabditis elegans model

Despite a pathotype concept, aeromonad virulence remains poorly understood, and difficult to predict. In addition, Aeromonas human infections often involve mixed infection, and 5-10% cases include two distinct aeromonads, with unknown an impact on virulence. The aim of this study was to understand aeromonad-mixed infection by studying the virulence of aeromonads recovered from human mixed infections, tested alone and in association in the Caenorhabditis elegans model. The genome content of virulence-associated gene failed to explain virulence synergy and to identify pathotypes although some virulence–associated genes present in some strains were absent from their companion strain (e.g., T3SS). Synergistic virulence observed between infectious isolates stresses to consider Aeromonas infection process at the community level and not should not be limited to the pathotype concept.

尽管存在致病型（pathotype）这一概念，但气单胞菌的致病机制仍未被充分阐明，且其毒力难以预测。此外，人类气单胞菌感染常为混合感染，其中5%-10%的病例涉及两种不同的气单胞菌，其对毒力的影响尚不清楚。本研究旨在探究气单胞菌混合感染的机制，具体方法为：对从人类混合感染病例中分离得到的气单胞菌分别单独测试其毒力，并以秀丽隐杆线虫（Caenorhabditis elegans）为模型测试其联合感染时的毒力。尽管部分菌株所携带的毒力相关基因在其配对的共感染菌株中缺失（例如三型分泌系统（T3SS）），但基于毒力相关基因的基因组特征分析，既无法解释毒力协同效应，也无法鉴定致病型。本研究观察到的感染分离株之间的毒力协同效应，提示我们应从群落层面考量气单胞菌的感染过程，而不应局限于致病型这一概念。