儿童迁延性细菌性支气管炎的呼吸道菌群特征及临床意义

The characteristics of respiratory tract microbiota and its clinical significance in children with protracted bacterial bronchitis

目的探讨儿童迁延性细菌性支气管炎（protracted bacterial bronchitis，PBB）的呼吸道菌群特征及临床意义。方法纳入年龄5个月～2岁，于2015年1月至2016年5月在深圳市儿童医院呼吸科住院的PBB患儿12例，匹配同年龄段的气管软化（tracheomalacia，TM）患儿12例作为对照。留取PBB和TM患儿的支气管肺泡灌洗液样本，进行细菌DNA提取。通过Illumina MiSeq TMII高通量测序平台对细菌DNA 16S rRNA V3－V4区进行高通量测序，对测序结果进行生物信息学分析。结果主成分分析提示，PBB组与TM组的呼吸道菌群组成有明显差异。PBB组和TM组的Shannon指数分别为1.683±0.703、2.324±0.142，Simpson指数分别为0.416±0.216、0.191±0.025，差异均有统计学意义（均P〈0.05），提示PBB组的菌群多样性低于TM组。在门水平，PBB组的放线菌门比例明显低于TM组[（0.215±0.228）%比（3.028±0.592）%，P〈0.01]；在属水平，PBB组乳球菌属[（13.464±7.319）%比（44.784±5.020）%，P＝0.000]、乳酸杆菌属[（0.153±0.076）%比（0.313±0.060）%，P〈0.01]、节细菌属[（0.024±0.018）%比（2.970±0.584）%，P〈0.01]等有益菌属比例下降，而流感嗜血杆菌属[（14.319±29.532）%比（0.047±0.127）%，P〈0.01]、假单胞菌属[（10.406±25.439）%比（7.228±0.948）%，P〈0.01]、埃希菌属[（0.432±0.441）%比（0.055±0.035）%，P＝0.000]等条件致病菌属比例明显上升。结论PBB患儿存在呼吸道菌群紊乱，菌群多样性下降，可能是PBB的发病机制之一。

ObjectiveTo explore the characteristics of respiratory tract microbiota and its clinical significance in children with protracted bacterial bronchitis （PBB）.MethodsTwelve children aged from 5 months to 2 years old with PBB （PBB group） and 12 age-matched tracheomalacia（TM） children （TM group） were included in this study, who were admitted into the Respiratory Department of Shenzhen Children′s Hospital.Their bronchoalveolar lavage fluid （BALF） samples were collected.Bacterial DNA was extracted from their BALF samples and the 16S rRNA V3-V4 region was sequenced by using Illumina MiSeq TMII system, and the findings were analyzed by bioinformatics methods.ResultsPrincipal component analysis revealed the difference in microbiota composition between 2 groups.Compared with TM group, PBB group exhibited lower microbial diversity： the Shannon indices were also 1.683±0.703 and 2.324±0.142 for PBB group and TM group respectively, and the differences were also significant（all P〈0.05）, and the Simpson indices were 0.416±0.216 and 0.191±0.025 for PBB group and TM group, respectively, and the diffe-rences were also significant（all P〈0.05）. The relative abundance of Actinobacteria was significantly lower in PBB group [（0.215±0.228）%]than that in TM group [（3.028±0.592）%]（P〈0.01）. The proportions of beneficial genera obviously decreased in PBB group, including Lactococcus [（13.464±7.319）% in PBB group, and （44.784±5.020）% in TM group, P〈0.01], Lactobacillus [（0.153±0.076）% in PBB group, and （0.313±0.060）% in TM group, P〈0.01], and Arthrobacter [（0.024±0.018）% in PBB group, and （2.970±0.584）% in TM group, P〈0.01]. On the other hand, the relative abundances of opportunistic pathogenic genera increased in PBB group significantly, including Haemophilus[（14.319±29.532）% in PBB group, and （0.047±0.127）% in TM group, P〈0.01], Pseudomonas[（10.406±25.439）% in PBB group, and （7.228±0.948）% in TM group, P〈0.01], and Escherichia [（0.432±0.441）% in PBB group, and （0.055±0.035）% in TM group, P〈0.01].ConclusionThese findings confirmed the existence of respiratory tract microbiotia dysbiosis in PBB, which probably was one of the pathogenetic mechanisms for PBB.