Molecular analysis of the endobronchial stent microbial biofilm reveals bacterial communities that associate with stent material and frequent fungal constituents

Endobronchial stents are increasingly used to treat airway complications in multiple conditions including lung transplantation but little is known about the biofilms that form on these devices. We applied deep sequencing to profile luminal biofilms of 46 endobronchial stents removed from 20 subjects primarily with lung transplantation-associated airway compromise. Microbial communities were analyzed by bacterial 16S rRNA and fungal ITS marker gene sequencing. Corynebacterium was the most common bacterial taxa across biofilm communities. Clustering analysis revealed three bacterial biofilm types: one low diversity and dominated by Corynebacterium; another was polymicrobial and characterized by Staphylococcus; and the third was polymicrobial and associated with Pseudomonas, Streptococcus, and Prevotella. Biofilm type was significantly correlated with stent material: covered metal with the Staphylococcus-type biofilm, silicone with the Corynebacterium-dominated biofilm, and uncovered metal with the polymicrobial biofilm. Subjects with sequential stents had frequent transitions between community types. Fungal analysis found Candida was most prevalent, Aspergillus was common and highly enriched in two of three stents associated with airway anastomotic dehiscence, and fungal taxa not typically considered pathogens were highly enriched in some stents. Thus, molecular analysis revealed a complex and dynamic endobronchial stent biofilm with three bacterial types that associate with stent material, a central role for Corynebacterium, and that both expected and unexpected fungi inhabit this unique niche. The current work provides a foundation for studies to investigate the relationship between stent biofilm composition and clinical outcomes, mechanisms of biofilm establishment, and strategies for improved stent technology and use in airway compromise.

支气管内支架（endobronchial stents）目前已愈发广泛地应用于多种病症引发的气道并发症治疗，其中涵盖肺移植相关病症，但学界对这类器械表面形成的生物被膜（biofilms）仍缺乏充分了解。本研究采用深度测序（deep sequencing）技术，对20名主要罹患肺移植相关气道损伤的受试者取出的46个支气管内支架的管腔生物被膜开展群落谱系分析。研究通过细菌16S核糖体RNA（16S rRNA）与真菌内转录间隔区（Internal Transcribed Spacer, ITS）标记基因测序，对微生物群落进行解析。棒状杆菌属（Corynebacterium）是所有被分析的生物被膜群落中最常见的细菌类群。聚类分析结果显示，共存在三种细菌生物被膜类型：其一为低多样性群落，以棒状杆菌属为主导；其二为多微生物群落，以葡萄球菌属（Staphylococcus）为特征类群；其三亦为多微生物群落，与假单胞菌属（Pseudomonas）、链球菌属（Streptococcus）及普雷沃菌属（Prevotella）的存在显著相关。生物被膜类型与支架材料存在显著关联：带覆膜金属支架对应葡萄球菌型生物被膜，硅胶支架对应棒状杆菌主导型生物被膜，而无覆膜金属支架则对应多微生物型生物被膜。接受序贯支架植入的受试者，其生物被膜群落类型常发生转换。真菌群落分析显示，念珠菌属（Candida）为最普遍的真菌类群；曲霉属（Aspergillus）较为常见，且在2个与气道吻合口漏（airway anastomotic dehiscence）相关的支架中呈现高度富集状态；部分支架中还高度富集了通常不被视作致病菌的真菌类群。综上，分子分析揭示了结构复杂且动态变化的支气管内支架生物被膜：存在三种与支架材料相关的细菌群落类型，棒状杆菌属发挥核心作用，且该独特生态位中同时存在已知与未知的真菌类群。本研究为后续探究支架生物被膜组成与临床结局的关联、生物被膜形成机制，以及优化支架技术与气道损伤治疗策略的相关研究奠定了坚实基础。