Effect of systemic glucocorticosteroids in the management of asthma and chronic obstructive pulmonary disease exacerbation on respiratory microbiota composition in the period of stability

The purpose of this study is to evaluate the ability of systemic glucocorticosteroids administered during the exacerbation of the disease to have a modifying effect on the qualitative and quantitative composition of the oropharyngeal microbiota.Material and methods. The study included 88 patients with COPD and 50 patients with stable asthma. The patients have had a history of observation for twelve months or more; they are characterized by the absence of exacerbations and systemic antibiotic therapy for four weeks or more prior to inclusion in the study. Also, all patients participating in the study were taken samples of oropharyngeal microbiota for isolating bacterial DNA and sequencing 16S rRNA gene sequences followed by the analysis of the taxonomic composition of the microbiota. Generalized linear model implemented in the R programming language version 3.1.0, glm2 package was used to identify the relationship between taxonomic composition of metagenomes and metadata.Results. The study suggests that the use of systemic glucocorticosteroids administered during the exacerbation of asthma and COPD modifies the composition of the respiratory microbiome in the period of stability increasing the oropharyngeal representation of non-pathogenic bacteria such as Bacteroidetes (including members of the genus Prevotella) and reducing bacterial contamination of oropharyngeal swabs by proteobacteria especially Streptococcus, and Haemophilus, which includes pathogens.