Asthma and chronic obstructive pulmonary disease (COPD) are both illnesses that are caused by chronic inflammation of the respiratory tract, and recent research suggests that the microbiota of the lower respiratory tract may influence the development of these two diseases. The upper respiratory tract, though, remained unstudied, until a new article was recently published in PLoS ONE. This article characterized the microbiome of the oropharynx (in the upper respiratory tract) to discover the association between these problems and the microbiome.
Samples were swabbed from the oropharynx of patients who were recently diagnosed with asthma and COPD, as well as from a healthy control group. Researchers performed 16S rRNA gene sequencing of the bacteria collected from the patients, in order to determine which bacteria were present. They found that there are few differences in microbiome diversity between asthma and COPD patients, however there was a prevalent presence of the bacteria Lactobacillus (phylum Firmicutes) and Pseudomonas (phylum Proteobacteria) in both, which were identified in only very small amounts in healthy patients. On the contrary, the upper respiratory tract of healthy individuals was found to be dominated by Streptococcus, Veillonella, Prevotella, and Neisseria, from the phylum Bacteroidetes, compared to individuals with asthma and COPD.
This study showed distinct differences in the microbiomes of diseased and healthy individuals. The researchers also note that the low abundance of Neisseria they observed in this study has also been seen in studies of smokers, meaning that this bacteria may be important to respiratory health. Further work is still needed, though, to determine if the bacteria identified in this study are contributing to the diseased individuals. Even if they are not, they could still potentially be used in diagnosis.