Changes in the microbiota of the upper airways and intestine in the treatment of acute respiratory infections in preschool children

Abstract

Introduction. The microbiota of the upper airways and intestine in preschool children is directly involved in protecting the growing body from acute respiratory infections (ARI), which are the most common infections in children, about 65% of them turn into recurrent respiratory infections (RRI). Aim. To establish changes in the microbiota of the upper airways and intestine in the treatment of ARI in preschool children.
 Materials and methods. The study involved sixty 1–6 year (Me = 3.38 years) frequently ill children. They were divided into 3 groups depending on the chosen treatment lasting 90 days. Children of group 1 (n = 20) underwent nutrition correction. Children of group 2 (n = 20) received additional probiotics. Children of group 3 (n = 20) received both nutritional correction and probiotics at the prescribed doses. Before and after treatment, the composition of the microbiota of the oropharyngeal zone and intestine was determined by genetic sequencing of the V3–V4 region of the 16S ribosomal RNA gene, followed by bioinformatic analysis. 
 Results. Significant differences were found mainly in the relative content of Firmicutes in the microbiota of patients treated. The content of Firmicutes in the microbiota of children receiving probiotics against the background of nutrition correction (30%) was significantly higher than in patients with nutrition correction (26.91%) and in children receiving only probiotics (25.95%). In patients of different groups, after treatment, a decrease in the content of Proteobacteria in the microbiota of the oropharyngeal zone was revealed. A significant decrease in the relative content of Bacteroidota (by more than 3 times) in 95% of patients, and a decrease in Proteobacteria (by more than 4.5 times) in 100% of patients was also found in the intestinal microbiota of group 3 patients treated with probiotics. In addition, there was a significant increase in the Firmicutes microbiota from 21.97% to 30.07% in 85% of patients, and an increase in the content of Actinobacteriota from 1.9% to 5.7% in 95% of patients. The relative content of undifferentiated microbiota after therapy was also significantly higher (70.08%) than before treatment (58.40%) in 85% of patients.