支气管扩张气道细菌微生物组学及与临床特征的相关性研究

Microbiological characteristics of airway bacteria in adult patients with bronchiectasis and their correlation with the clinical features

目的对成人支气管扩张(简称支扩)患者气道细菌微生物组学特点及与临床特征的相关性进行研究。方法将2017年10月—2018年4月四川大学华西医院呼吸与危重症医学科门诊确诊为支扩的患者归为支扩组,对照组为体检发现肺部结节(直径小于10 mm)需行支气管镜检查的患者,两组受试者4周内均未用过抗生素及糖皮质激素,无其他呼吸道疾病。支扩组收集其病变部位的支气管肺泡灌洗液(bronchoalveolar lavage fluid,BALF),对照组收集肺结节对侧支气管下叶基底段的BALF,均进行细菌培养及16S rRNA基因测序。结果共纳入17例支扩患者和6例对照组患者。其中8例支扩患者处于为稳定期,9例支扩患者处于急性加重期。支扩患者分为细菌培养菌阳组和菌阴组,菌阳组Shannon指数较菌阴组和对照组显著降低,当BALF行16S rRNA基因测序Shannon指数≤4.5时对菌阳的预测的敏感性为83.3%,特异性为90.9%。支扩患者稳定期与急性加重期比较,结果显示急性加重期细菌的平均丰度更高、平均样本细菌分布均匀性较低,Shannon指数与患者发生急性加重呈负相关,当Shannon指数<5.0时预测支扩患者发生急性加重敏感性为77.8%,特异性为100.0%。结论16S rRNA基因测序结果中的Shannon指数对支扩急性加重有一定的预测价值。16S rRNA基因测序结合细菌培养结果,有助于指导临床医生提供更精准的治疗方案。

Objective To analyze the microbiological characteristics of airway bacteria in adult patients with bronchiectasis and to analyze their correlation with the clinical features.Methods Patients diagnosed with bronchiectasis in the Department of Respiratory and Critical Care Medicine of West China Hospital of Sichuan University from October 2017 to April 2018 were classified into the bronchiectasis group,while the control group was those who were found to have pulmonary nodules(diameter less than 10 mm)requiring bronchoscopy by physical examination.All subjects in both groups had not used antibiotics or hormones within 4 weeks and had no other respiratory diseases.Bronchoalveolar lavage fluid(BALF)from the lesion site of the branchial expansion group was collected,and BALF from the basal segment of the contralateral inferior bronchial lobe of the pulmonary nodule was collected in the control group.Bacterial culture and 16S rRNA gene sequencing were performed in both groups.Results Seventeen cases and six controls were enrolled in this study and the BALF specimens were collected.Eight cases were in stable period and nine cases were in acute period.The case group was divided into the bacteria-positive group and negative group based on bacterial culture of BALF.Shannon index in the bacteria-positive group was significantly lower than the bacteria-negative group and the control group.And Shannon index showed a negative correlation with positive bacterial culture in BALF.When Shannon index≤4.5 was used to predict positive bacterial culture,the sensitivity and specificity were 83.3%and 90.9%respectively.The average relative abundance of bacteria was higher and the average sample distribution uniformity was lower in patients with acute period,compared with those in patients with stable period.Shannon index was negatively correlated with the acute exacerbation in patients.When Shannon index<5.0 was used to predict acute exacerbation,the sensitivity and specificity were 77.8%and 100.0%,respectively.Conclusions Shannon index in 16S rRNA gene sequencing results has certain predictive value for acute exacerbation stage.16S rRNA gene sequencing combined with bacterial culture results can help guide clinicians to provide more precise treatment plans.