Department of Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Goethe-University Frankfurt am Main, Frankfurt am Main, Germany.
Environ Microbiol. 2019 Jul;21(7):2212-2230. doi: 10.1111/1462-2920.14565. Epub 2019 Mar 12.
Multidrug resistant (MDR) pathogens are one of the most pressing challenges of contemporary health care. Acinetobacter baumannii takes a predominant position, emphasized in 2017 by the World Health Organization. The increasing emergence of MDR strains strengthens the demand for new antimicrobials. Possible targets for such compounds might be proteins involved in resistance against low water activity environments, since A. baumannii is known for its pronounced resistance against desiccation stress. Despite the importance of desiccation resistance for persistence of this pathogen in hospitals, comparable studies and precise data on this topic are rare and the mechanisms involved are largely unknown. This review aims to give an overview of the studies performed so far and the current knowledge on genes and proteins important for desiccation survival. 'Osmotic stress' is not identical to 'desiccation stress', but the two share the response of bacteria to low water activities. Osmotic stress resistance is in general studied much better, and in recent years it turned out that accumulation of compatible solutes in A. baumannii comprises some special features such as the bifunctional enzyme MtlD synthesizing the unusual solute mannitol. Furthermore, the regulatory pathways, as understood today, will be discussed.
耐多药（MDR）病原体是当代医疗保健面临的最紧迫挑战之一。鲍曼不动杆菌占据主要地位，2017 年世界卫生组织对此加以强调。MDR 菌株的不断出现加剧了对新型抗菌药物的需求。此类化合物的可能靶标可能是参与抵抗低水活度环境的蛋白质，因为众所周知，鲍曼不动杆菌对干燥胁迫具有明显的抗性。尽管干燥抗性对于该病原体在医院中的持续存在非常重要，但关于该主题的可比研究和精确数据很少，涉及的机制在很大程度上仍不清楚。本文旨在概述迄今为止进行的研究以及与干燥存活相关的重要基因和蛋白质的现有知识。“渗透压胁迫”与“干燥胁迫”并不相同，但两者都具有细菌对低水活度的反应。一般来说，渗透压抗性的研究要好得多，近年来发现，鲍曼不动杆菌中相容溶质的积累具有一些特殊特征，例如双功能酶 MtlD 合成不寻常的溶质甘露醇。此外，还将讨论今天所理解的调节途径。
