Enrichment of lung microbiome with supraglottic taxa is associated with increased pulmonary inflammation

Background: The lung microbiome of healthy individuals frequently harbors oral organisms. Despite evidence that micro-aspiration is commonly associated with smoking-related lung diseases, the effects of lung microbiome enrichment with upper airway taxa on inflammation has not been studied. We hypothesize that the presence of oral microorganisms in the lung microbiome is associated with enhanced pulmonary inflammation. Methods: We sampled bronchoalveolar lavage (BAL) from the lower airways of 29 asymptomatic subjects (9 never-smokers, 14 former-smokers and 6 current-smokers). We quantified, amplified, and sequenced 16S rRNA genes from BAL samples by qPCR and 454 sequencing. Pulmonary inflammation was assessed by exhaled nitric oxide (eNO), BAL lymphocytes and neutrophils. Results: BAL had lower total 16S than supraglottic samples and higher than saline background. Bacterial communities in the lower airway clustered in two distinct groups that we designated... (for more see dbGaP study page.)

研究背景：健康个体的肺部微生物组通常定植有口腔微生物。尽管已有证据表明微量吸入常与吸烟相关肺部疾病存在关联，但目前尚未有研究探讨上呼吸道菌群类群富集肺部微生物组对肺部炎症的影响。本研究假设肺部微生物组中存在口腔微生物与肺部炎症加剧具有相关性。研究方法：本研究纳入29名无症状受试者，对其下呼吸道采集支气管肺泡灌洗（bronchoalveolar lavage, BAL）样本，其中9名从未吸烟、14名为既往吸烟者、6名为当前吸烟者。通过实时荧光定量PCR（quantitative PCR, qPCR）与454测序技术，对支气管肺泡灌洗液样本中的16S rRNA基因进行定量、扩增及测序。肺部炎症水平通过呼出气一氧化氮（exhaled nitric oxide, eNO）、支气管肺泡灌洗液中的淋巴细胞与中性粒细胞水平进行评估。研究结果：支气管肺泡灌洗液样本的16S总基因拷贝数低于声门上样本，且高于生理盐水背景样本。下呼吸道的细菌群落可分为两个显著不同的类群，本研究将其命名为……（更多详情请参见dbGaP研究页面）