Acinetobacter baumannii is a nosocomial pathogen that causes multi-drug resistant infections mainly in immunocompromised patients. Although this gram-negative species lacks flagella, it is able to move over wet surfaces through a not well characterized type of movement known as surface-associated motility. In this study we demonstrate through the inactivation of the A1S_2813 gene (coding a CheW-like protein) and recA (coding a DNA damage repair and recombination protein) that both genes are involved in the surface-associated motility and chemotaxis of A. baumannii ATCC 17978 strain. In addition, we also point out that the lack of either RecA or CheW-like proteins reduces its virulence in the Caenorhabditis elegans and the Galleria mellonella animal models. Furthermore, we show through co-immunoprecipitation assays that the CheW-like protein and RecA interact and that this interaction is abolished by the introduction of the mutation S97A in one of the domains of CheW-like protein that is structurally conserved in Salmonella enterica and necessary for the RecA-CheW interaction in this bacterial species. Finally, we show that the replacement of the wild-type CheW-like protein by that presenting the S97A mutation impairs surface-associated motility, chemotaxis and virulence of A. baumannii strain ATCC 17978.

中文翻译：

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RecA和CheW样蛋白之间的直接相互作用是表面相关的运动性，趋化性和鲍曼不动杆菌ATCC 17978的全部毒力所必需的。

鲍曼不动杆菌是一种医院病原体，主要在免疫功能低下的患者中引起多重耐药性感染。尽管这种革兰氏阴性菌缺乏鞭毛，但它能够通过一种不十分清楚的运动类型在湿表面上运动，这种运动称为表面相关运动。在这项研究中，我们通过灭活A1S_2813基因（编码CheW样蛋白）和recA（编码DNA损伤修复和重组蛋白）来证明这两个基因都与鲍氏不动杆菌ATCC的表面相关运动性和趋化性有关。 17978株。此外，我们还指出，在秀丽隐杆线虫和黑麦草廊动物模型中，缺乏RecA或类似CheW的蛋白质会降低其毒力。此外，我们通过共同免疫沉淀试验表明，CheW样蛋白和RecA相互作用，并且通过在结构上在肠杆菌沙门氏菌中保守的CheW样蛋白的一个域中引入突变S97A消除了这种相互作用该细菌物种中的RecA-CheW相互作用。最后，我们表明，通过呈现S97A突变替代野生型CheW样蛋白会损害鲍曼不动杆菌ATCC 17978的表面相关运动性，趋化性和毒性。