Dingemans Jozef, Monsieurs Pieter, Yu Sung-Huan, Crabbé Aurélie, Förstner Konrad U, Malfroot Anne, Cornelis Pierre, Van Houdt Rob
Department of Bioengineering Sciences, Research Group Microbiology, Vrije Universiteit Brussel, and VIB Structural Biology, Brussels, Belgium Unit of Microbiology, Expert Group Molecular and Cellular Biology, Institute for Environment, Health and Safety, Belgian Nuclear Research Centre (SCK CEN), Belgium.
Unit of Microbiology, Expert Group Molecular and Cellular Biology, Institute for Environment, Health and Safety, Belgian Nuclear Research Centre (SCK CEN), Belgium.
mBio. 2016 Aug 2;7(4):e00813-16. doi: 10.1128/mBio.00813-16.
Chronic colonization of the lungs by Pseudomonas aeruginosa is one of the major causes of morbidity and mortality in cystic fibrosis (CF) patients. To gain insights into the characteristic biofilm phenotype of P. aeruginosa in the CF lungs, mimicking the CF lung environment is critical. We previously showed that growth of the non-CF-adapted P. aeruginosa PAO1 strain in a rotating wall vessel, a device that simulates the low fluid shear (LS) conditions present in the CF lung, leads to the formation of in-suspension, self-aggregating biofilms. In the present study, we determined the phenotypic and transcriptomic changes associated with the growth of a highly adapted, transmissible P. aeruginosa CF strain in artificial sputum medium under LS conditions. Robust self-aggregating biofilms were observed only under LS conditions. Growth under LS conditions resulted in the upregulation of genes involved in stress response, alginate biosynthesis, denitrification, glycine betaine biosynthesis, glycerol metabolism, and cell shape maintenance, while genes involved in phenazine biosynthesis, type VI secretion, and multidrug efflux were downregulated. In addition, a number of small RNAs appeared to be involved in the response to shear stress. Finally, quorum sensing was found to be slightly but significantly affected by shear stress, resulting in higher production of autoinducer molecules during growth under high fluid shear (HS) conditions. In summary, our study revealed a way to modulate the behavior of a highly adapted P. aeruginosa CF strain by means of introducing shear stress, driving it from a biofilm lifestyle to a more planktonic lifestyle.
Biofilm formation by Pseudomonas aeruginosa is one of the hallmarks of chronic cystic fibrosis (CF) lung infections. The biofilm matrix protects this bacterium from antibiotics as well as from the immune system. Hence, the prevention or reversion of biofilm formation is believed to have a great impact on treatment of chronic P. aeruginosa CF lung infections. In the present study, we showed that it is possible to modulate the behavior of a highly adapted transmissible P. aeruginosa CF isolate at both the transcriptomic and phenotypic levels by introducing shear stress in a CF-like environment, driving it from a biofilm to a planktonic lifestyle. Consequently, the results obtained in this study are of great importance with regard to therapeutic applications that introduce shear stress in the lungs of CF patients.
铜绿假单胞菌在肺部的慢性定植是囊性纤维化（CF）患者发病和死亡的主要原因之一。为深入了解CF肺部中铜绿假单胞菌的特征性生物膜表型，模拟CF肺部环境至关重要。我们之前表明，非CF适应型铜绿假单胞菌PAO1菌株在旋转壁容器（一种模拟CF肺部低流体剪切力（LS）条件的装置）中生长，会导致形成悬浮的、自我聚集的生物膜。在本研究中，我们确定了在LS条件下，一种高度适应的、可传播的铜绿假单胞菌CF菌株在人工痰液培养基中生长所伴随的表型和转录组变化。仅在LS条件下观察到了强大的自我聚集生物膜。在LS条件下生长导致参与应激反应、藻酸盐生物合成、反硝化作用、甘氨酸甜菜碱生物合成、甘油代谢和细胞形状维持的基因上调，而参与吩嗪生物合成、VI型分泌和多药外排的基因下调。此外，一些小RNA似乎参与了对剪切应力的反应。最后，发现群体感应受到剪切应力的轻微但显著影响，导致在高流体剪切力（HS）条件下生长期间自诱导分子的产量更高。总之，我们的研究揭示了一种通过引入剪切应力来调节高度适应的铜绿假单胞菌CF菌株行为的方法，使其从生物膜生活方式转变为更浮游的生活方式。
铜绿假单胞菌形成生物膜是慢性囊性纤维化（CF）肺部感染的标志之一。生物膜基质可保护这种细菌免受抗生素以及免疫系统的攻击。因此，预防或逆转生物膜形成被认为对慢性铜绿假单胞菌CF肺部感染的治疗有很大影响。在本研究中，我们表明在类似CF的环境中引入剪切应力，有可能在转录组和表型水平上调节高度适应的可传播铜绿假单胞菌CF分离株的行为，使其从生物膜生活方式转变为浮游生活方式。因此，本研究获得的结果对于在CF患者肺部引入剪切应力的治疗应用具有重要意义。
