Rationale: Asthma is a chronic inflammatory airway disease. Microbial colonization of the respiratory tract may have a role in the chronic inflammatory process. Methods : We recruited 23 non-smoking patients with stable asthma and 9 healthy subjects in Guangzhou, and obtained induced sputum samples for 16S ribosomal RNA analysis. The V3-V5 regions of bacterial 16S rRNA genes were amplified and sequenced by 454 pyrosequencing. Sequences were assigned to bacterial taxa by comparing them with 16s rRNA sequences in the Ribosomal Database Project (BGI, Shenzhen). Results : Asthmatics with an ACT score of 22.8±1.8 had lower %FEV1 predicted (73.4 vs 99.4; p0.001) and higher sputum eosinophils (24.0 % vs 0.5%; p0.001). The species richness was significantly decreased in asthmatic patients compared with control subjects (85.0±20.6 vs 107.9±15.2 taxa; p=0.005). 16S rRNA sequencing detected bacteria containing 6 major phyla: Bacteroidetes, Firmicutes, Proteobacteria,Fusobacterium, Actinobacteria and Spirochaetes, with the first 3 accounting for 90%of all sequences. Actinobacteria (2.2% vs 0.6%, P=0.02) were found more frequently in asthmatic samples. Conclusions : Sputum from asthmatic patients has an altered microbial composition with lower species richness in the respiratory tract compared with non-asthmatics. The corresponding biological effect on airway inflammation remains to be determined. Supported by State Key Laboratory of Respiratory Diseases, Guangzhou Medical University.
Zhang et al. (Mon,) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: