Naijian Li1, Rihuang Qiu1, Zhaowei Yang1, Jing Li1, Kian Fan Chung2, Nanshan Zhong1, Qingling Zhang3. 1. State Key Laboratory of Respiratory Disease, The First Affiliated Hospital, Guangzhou Medical University, Guangzhou, China. 2. Airways Disease Section, National Heart & Lung Institute, Imperial College London, & Biomedical Research Unit, Royal Brompton Hospital, London, SW3, UK. 3. State Key Laboratory of Respiratory Disease, The First Affiliated Hospital, Guangzhou Medical University, Guangzhou, China. Electronic address: zqling68@hotmail.com.
Abstract
BACKGROUND: Altered composition of airway microbiota has been reported in subjects suffering from asthma but its relation to eosinophilic phenotype is unclear. OBJECTIVE: To examine the relationship between sputum microbiota, asthma severity and inflammatory type in asthmatic subjects from Guangzhou, China. METHODS: Induced sputum samples were obtained from 49 non-smoking asthma patients, 25 severe and 24 non-severe, and 15 healthy subjects. Total DNA was amplified using primers specific for the V3-V5 hypervariable region of bacterial 16s rRNA and sequenced using the 454 GS FLX sequencer. Sequences were assigned to bacterial taxa by comparing them with 16s rRNA sequences in the Ribosomal Database Project. RESULTS: Sputum eosinophil counts were higher and FEV1 (% predicted) was lower in severe compared to non-severe asthmatics. There were no significant differences in operational taxonomic unit (OTU) numbers at the phylum level and in diversity scores between non-severe asthmatics and severe asthmatics, and healthy subjects. At the family level, Porphyromonadaceae was most abundant in healthy subjects whereas Pseudomonadaceae and Enterobacteriaceae were higher in severe asthmatics compared to non-severe asthmatics (p < 0.05). Actinomycetaceae was particularly abundant in eosinophilic asthma patients compared to non-eosinophilic asthma (p = 0.011). Bacteroidaceae was positively correlated with FEV1 in all subjects (r = 0.335, p < 0.01), whereas body mass index was negatively associated with the number of species observed (r = -0.3, p < 0.05). Principal component analysis confirmed the positive association of Actinomycetaceae and Enterobacteriaceae abundance with eosinophilic asthma. CONCLUSION: Patients with asthma have an altered airway microbiota, with specific bacteria associated with severe asthma and the eosinophilic inflammatory phenotype.
BACKGROUND: Altered composition of airway microbiota has been reported in subjects suffering from asthma but its relation to eosinophilic phenotype is unclear. OBJECTIVE: To examine the relationship between sputum microbiota, asthma severity and inflammatory type in asthmatic subjects from Guangzhou, China. METHODS: Induced sputum samples were obtained from 49 non-smoking asthma patients, 25 severe and 24 non-severe, and 15 healthy subjects. Total DNA was amplified using primers specific for the V3-V5 hypervariable region of bacterial 16s rRNA and sequenced using the 454 GS FLX sequencer. Sequences were assigned to bacterial taxa by comparing them with 16s rRNA sequences in the Ribosomal Database Project. RESULTS: Sputum eosinophil counts were higher and FEV1 (% predicted) was lower in severe compared to non-severe asthmatics. There were no significant differences in operational taxonomic unit (OTU) numbers at the phylum level and in diversity scores between non-severe asthmatics and severe asthmatics, and healthy subjects. At the family level, Porphyromonadaceae was most abundant in healthy subjects whereas Pseudomonadaceae and Enterobacteriaceae were higher in severe asthmatics compared to non-severe asthmatics (p < 0.05). Actinomycetaceae was particularly abundant in eosinophilic asthma patients compared to non-eosinophilic asthma (p = 0.011). Bacteroidaceae was positively correlated with FEV1 in all subjects (r = 0.335, p < 0.01), whereas body mass index was negatively associated with the number of species observed (r = -0.3, p < 0.05). Principal component analysis confirmed the positive association of Actinomycetaceae and Enterobacteriaceae abundance with eosinophilic asthma. CONCLUSION: Patients with asthma have an altered airway microbiota, with specific bacteria associated with severe asthma and the eosinophilic inflammatory phenotype.
Authors: Francesco Antonio Salzano; Luigi Marino; Giovanni Salzano; Riccardo Maria Botta; Giovanni Cascone; Umberto D'Agostino Fiorenza; Carmine Selleri; Vincenzo Casolaro Journal: J Immunol Res Date: 2018-06-03 Impact factor: 4.818