轻度支气管哮喘儿童的诱导痰菌群特征

The characteristics of induced sputum microbiota of children with mild bronchial asthma

目的探讨轻度支气管哮喘儿童的诱导痰菌群特征及临床意义。方法纳入年龄为6~12周岁于2018年11月至2019年1月在深圳市儿童医院呼吸科门诊定期复诊的轻度支气管哮喘患儿51例(哮喘组),留取诱导痰,匹配同年龄段97例健康无过敏儿童的口咽拭子作为对照。诱导痰及口咽拭子提取总DNA并扩增,对16S rRNA基因进行高通量测序并对测序结果进行生物信息学分析。结果NMDS分析结果显示哮喘组与健康对照组研究对象菌群结构存在差异;哮喘组的诱导痰菌群多样性指数(Shannon index)高于健康对照组(2.34±0.53 vs 1.87±0.50,P<0.05)。门水平分析显示,哮喘组与健康对照组的菌群均主要为厚壁菌门(38.34%vs 44.74%,P<0.05)、变形杆菌门(31.14%vs 19.78%,P<0.05)、拟杆菌门(14.59%vs 20.52%,P<0.05)、放线菌门(10.41%vs 7.85%,P<0.05)和梭杆菌门(2.82%vs 6.67%,P<0.05),但两组之间的构成比有明显差异。与健康对照组相比,在属水平上哮喘组韦荣球菌属(5.27%vs 8.96%)、普雷沃菌属(8.38%vs 17.35%)、罗斯菌属(1.50%vs 5.46%)、纤毛菌属(1.37%vs 4.39%)等非条件致病菌属比例明显下降(均P<0.05),而嗜血杆菌属(9.83%vs 6.17%)、卟啉单胞菌属(2.48%vs 1.41%)、莫拉菌属(5.66%vs 0.42%)、诺卡菌属(3.40%vs 0.00%)等条件致病菌属比例明显上升(均P<0.05)。结论尽管轻度支气管哮喘患儿已临床控制,但诱导痰内菌群仍存在结构紊乱。气道菌群紊乱可能是儿童支气管哮喘的发病机制之一。除了致病菌属外,非致病菌菌属的构成变化可能也是儿童哮喘的一个发生机制。

Objective To explore the characteristics of induced sputum microbiota of children with mild bronchial asthma and its clinical significance. Methods We collected induced sputum samples from 51 children with mild asthma aged between 6 and 12 years old, who were regularly followed up in the respiratory clinic in our hospital from Nov 2018 to Jan 2019. And 97 age-matched oropharyngeal swab samples were collected as healthy controls. Bacterial DNA was extracted from these samples. The regions of 16 S rRNA were sequenced and analyzed with bioinformatics methods. Results The NMDS analysis revealed the difference in the composition of microbiota between these two groups. Higher microbial diversity was detected in asthma group(2.34±0.53 vs 1.87±0.50, P<0.05 for Shannon index). Although the core microbiota including the phyla Firmicutes(38.34% vs 44.74%, P<0.05), Proteobacteria(31.14% vs 19.78%, P<0.05), Bacteroidetes(14.59% vs 20.52%, P<0.05), Actinobacteria(10.41% vs 7.85%, P<0.05) and Fusobacteria(2.82% vs 6.67%, P<0.05) were the same in the two groups, the composition ratios of these five phyla were obviously different between the two groups. Compared with healthy controls, the proportions of non-conditional pathogenic generas including Veillonella(2.82% vs 6.67%,P<0.05), Prevotella(8.38% vs 17.35%), Rothia(1.50% vs 5.46%), and Leptotrichia(1.37% vs 4.39%) were less(all P<0.05), and those of opportunistic pathogenic generas from the phyla Proteobacteria including Haemophilus(9.83% vs 6.17%), Porphyromonas(2.48% vs 1.41%), Moraxella(5.66% vs 0.42%), and Nocardia(3.40% vs 0.00%) were greater(all P<0.05). Conclusion Although the symptoms of these children with mild asthma were controlled, the dysbiosis still existed in the induced sputum microbiotia. These findings confirmed that the dysbiosis of respiratory tract microbiotia is possibly one of pathogensises of children′s asthma. Besides the generas from Proteobacteria, the changes in the composition ratio of non-conditional pathogenic generas are possibly involved in pathogensises of children′s asthma.