<i>Burkholderia cenocepacia</i> and <i>Pseudomonas aeruginosa</i> in dual-species models: Insights into population distribution, antibiotic susceptibility, and virulence

Multispecies biofilms are communities composed of different microorganisms embedded in an auto-synthesized polymeric matrix. <i>Pseudomonas aeruginosa</i> and <i>Burkholderia cenocepacia</i> are two multidrug-resistant and biofilm-forming opportunistic pathogens often found in the lungs of people living with cystic fibrosis. In this context, planktonic, static, and dynamic biofilms and <i>in vivo</i> models of both species were optimized in this work to understand their population dynamics, disposition, virulence, and antibiotic susceptibility. From the coculture models optimized in this work, we determined that <i>B. cenocepacia</i> grows in a clustered, aggregative manner at the bottom layers of biofilms, in close contact with <i>P. aeruginosa</i>, that tends to occupy the top layers. Their coexistence increases virulence-related gene expression in both species at early stages of coinfection and in <i>in vivo</i> models, while there was a general downregulation of virulence-related genes after longer coexistence periods as they eventually reach a non-competitive stage during chronic infections. When evaluating antimicrobial susceptibility, a decrease of antimicrobial tolerance was observed in both species when co-cultured. These findings shed light on the differential behavior of <i>P. aeruginosa</i> and <i>B. cenocepacia</i> in dual-species systems, stressing the relevance of multispecies studies in the clinical context.

多物种生物被膜（multispecies biofilms）是由多种微生物嵌入自主合成的聚合物基质所构成的群落。铜绿假单胞菌（Pseudomonas aeruginosa）与伯克霍尔德菌（Burkholderia cenocepacia）均为多重耐药、可形成生物被膜的机会致病菌，常定植于囊性纤维化患者的肺部。本研究针对这两种菌株优化了浮游态、静态及动态生物被膜模型，以及体内（in vivo）模型，以探究其种群动态、空间分布、毒力特性及抗生素敏感性。基于本研究构建的共培养模型，我们发现伯克霍尔德菌（B. cenocepacia）以簇状聚集的方式生长于生物被膜底层，并与占据顶层的铜绿假单胞菌（Pseudomonas aeruginosa）紧密接触。二者共存可在共感染早期及体内模型中上调两种菌株的毒力相关基因表达水平；但随着共培养时长延长，由于慢性感染过程中二者最终进入非竞争阶段，毒力相关基因的表达普遍出现下调。在评估抗菌敏感性时，研究观察到共培养状态下两种菌株的抗菌耐受性均有所降低。本研究结果阐明了铜绿假单胞菌与伯克霍尔德菌在双物种体系中的差异化行为，强调了多物种研究在临床场景中的重要意义。

搜集汇总

背景与挑战

背景概述

该数据集聚焦于铜绿假单胞菌和洋葱伯克霍尔德菌这两种多重耐药病原体在双物种模型中的相互作用，通过优化生物膜和体内模型，揭示了它们在种群分布、抗生素敏感性和毒力方面的动态变化。研究发现，两种菌在共培养时呈现分层分布，早期共感染增加毒力基因表达，但长期共存后下调，且共培养降低了抗菌耐受性，强调了多物种研究在临床环境中的重要性。