D1.472 - Features of the intestinal microbiota composition in infants with allergy: comparison of two diagnostic methods

Disorders of the intestinal microbiota are an important pathogenetic link in various diseases. Studying the features of the intestinal microbiota composition in infants with allergy is necessary for successful targeted correction.

Objective: to compare the diagnostic capabilities of two methods for assessing the intestinal microbiota composition in infants with allergy.

60 infants with allergy to food, respiratory and household allergens were included in the cross-sectional study: group I (n=37, the first year of life) at the age of 7 [6; 9] months old and group II (n=23, the second year of life) at the age of 16 [15; 19] months old. The intestinal microbiota composition was simultaneously studied in all patients using the metagenomic analysis of 16S rRNA gene fragment sequencing method, as well as the culture-based method. 

Both methods showed similar data when assessing the content of Bifidobacterium and Enterococcus in the microbiota. A decrease in the level of these microbes was revealed in infants of group II compared with those of group I, which reflects the normal age dynamics of the microbiota composition. In contrast to the culture-based method, metagenomic sequencing revealed a reliable increase in Lactobacillum in the microbiota of group II patients. The culture-based method demonstrated a decrease in the number of patients with elevated levels of Clostridium in group II, while according to metagenomic sequencing data, their species diversity increased in group II patients. The bacteriological method made it possible to identify patients (from 7 to 25%) in groups I and II, whose intestinal microbiota contained elevated levels of opportunistic microbes – Proteus spp., Staphylococcus aureus, Klebsiella spp., Citrobacter spp. When assessed by metagenomic sequencing, the content of these microorganisms in both groups was estimated to be low and statistically insignificant. 

Each of the presented methods has its own advantages, due to which they complement each other. The culture-based method retains its importance for the diagnostics of gut dysbiosis, as it provides quantitative characteristics of the microorganisms` content. At the same time, the metagenomic sequencing method makes it possible to assess bacterial diversity, including the species level, as well as the dynamics of the intestinal microbiota composition against the background of the allergic process course.