Shewaramani Sonal, Kassen Rees
Department of Biology, University of Ottawa, Ottawa, ON, Canada.
Front Microbiol. 2022 Aug 17;13:953964. doi: 10.3389/fmicb.2022.953964. eCollection 2022.
, a ubiquitous opportunistic pathogen, is a leading cause of chronic infection of airways in cystic fibrosis () patients. Chronic infections typically arise from colonization by environmental strains, followed by adaptation of to the conditions within the airway. It has been suggested that oxygen availability can be an important source of selection causing trait changes associated with the transition to chronic infection, but little data exist on the response of to varying levels of oxygen. Here, we use a diverse collection of strains recovered from both patients and environmental sources to evaluate the role of oxygen availability in driving adaptation to the lung while also accounting for phylogenetic relatedness. While we can detect a signal of phylogeny in trait responses to oxygen availability, niche of origin is a far stronger predictor. Specifically, strains isolated from the lungs of patients are more sensitive to external oxidative stress but more resistant to antibiotics under anoxic conditions. Additionally, many, though not all, patho-adaptive traits we assayed are insensitive to oxygen availability. Our results suggest that inferences about trait expression, especially those associated with the transition to chronic infection, depend on both the available oxygen and niche of origin of the strains being studied.
铜绿假单胞菌是一种普遍存在的机会致病菌，是囊性纤维化（CF）患者气道慢性感染的主要原因。慢性感染通常源于环境菌株的定植，随后铜绿假单胞菌适应CF气道内的条件。有人提出，氧气供应可能是导致与向慢性感染转变相关性状变化的重要选择来源，但关于铜绿假单胞菌对不同氧气水平反应的数据很少。在这里，我们使用从CF患者和环境来源收集的多种铜绿假单胞菌菌株，评估氧气供应在推动适应CF肺部过程中的作用，同时考虑系统发育相关性。虽然我们可以在对氧气供应的性状反应中检测到系统发育信号，但起源生态位是一个更强的预测因子。具体而言，从CF患者肺部分离的菌株对外部氧化应激更敏感，但在缺氧条件下对抗生素更具抗性。此外，我们检测的许多（尽管不是全部）致病适应性性状对氧气供应不敏感。我们的结果表明，关于性状表达的推断，尤其是那些与向慢性感染转变相关的推断，取决于所研究菌株的可用氧气和起源生态位。
