Institute of Environmental Biotechnology, Graz University of Technology, Graz, Austria.
Division of Infectious Diseases, Department of Internal Medicine, Medical University of Graz, Graz, Austria; BioTechMed Graz, Inter-university Cooperation Platform, Graz, Austria.
J Hazard Mater. 2022 Jan 15;422:126836. doi: 10.1016/j.jhazmat.2021.126836. Epub 2021 Aug 8.
Multi-species biofilms are more resistant against stress compared to single-species biofilms. However, the mechanisms underlying this common observation remain elusive. Therefore, we studied biofilm formation of well-known opportunistic pathogens (Acinetobacter baumanii, Enterococcus faecium, Escherichia coli, Staphylococcus haemolyticus and Stenotrophomonas maltophilia) in various approaches. Synergistic effects in their multi-species biofilms were observed. Using metatranscriptomics, changes in the gene expression of the involved members became evident, and provided explanations for the improved survivability under nutrient limitation and exposure to disinfectants. Genes encoding proteins for vitamin B6 synthesis and iron uptake were linked to synergism in the multi-species biofilm under nutrient-limited conditions. Our study indicates that sub-lethal concentrations of an alcohol-based disinfectant enhance biofilm yields in multi-species assemblages. A reduction of the dominant taxa in the multi-species biofilm under disinfectant pressure allowed minor taxa to bloom. The findings underline the importance of minor but antimicrobial-resistant species that serve as "protectors" for the whole assemblage due to upregulation of genes involved in defence mechanisms and biofilm formation. This ultimately results in an increase in the total yield of the multi-species biofilm. We conclude that inter-species interactions may be crucial for the survival of opportunistic pathogens; especially under conditions that are typically found under hospital settings.
与单物种生物膜相比，多物种生物膜更能抵抗压力。然而，这种常见现象的背后机制仍难以捉摸。因此，我们以多种方式研究了众所周知的机会性病原体（鲍曼不动杆菌、屎肠球菌、大肠杆菌、溶血葡萄球菌和嗜麦芽窄食单胞菌）的生物膜形成。在它们的多物种生物膜中观察到协同作用。通过宏转录组学，涉及成员的基因表达变化变得明显，并为在营养限制和消毒剂暴露下提高生存能力提供了解释。编码维生素 B6 合成和铁摄取蛋白的基因与营养受限条件下多物种生物膜中的协同作用有关。我们的研究表明，亚致死浓度的酒精基消毒剂可增强多物种组合中的生物膜产量。在消毒剂压力下，多物种生物膜中优势类群的减少允许次要类群的繁荣。这些发现强调了次要但具有抗药性的物种的重要性，由于参与防御机制和生物膜形成的基因上调，它们充当整个集合的“保护者”。这最终导致多物种生物膜的总产量增加。我们得出结论，种间相互作用可能对机会性病原体的生存至关重要；特别是在医院环境中通常发现的条件下。
