Alteration of the intestinal flora in children after antibiotic treatment explored using 16S rRNA sequencing

Background: During the critical period of intestinal flora establishment, children are infected, and their flora types and numbers are unstable and vulnerable to environmental influences. Antibiotic therapy is one of the leading causes of intestinal flora dysbiosis in children, but the underlying mechanism is still unclear. In this study, we investigated the changes in the characteristics of the intestinal flora in children after antibiotic treatment from a microscopic perspective via 16S rRNA sequencing technology, which can help clarify the effects of antibiotics on children's intestinal flora and provide a basis for the diagnosis and treatment of antibiotic-related diseases. Methods: Fifty-seven children with respiratory infectious diseases were recruited for this study. The patients were divided into a study group (AG) and a control group (NG) according to whether they were receiving antibiotics. Three different antibiotics were used in the AG group (28 patients): Meloxicillin Sulbactam (Suzhou Erye Pharmaceutical Co., Ltd.), Ceftriaxone (Shenzhen Lizhi Pharmaceutical Co., Ltd.), and Azithromycin (Hainan Puri Pharmaceutical Co., Ltd.). The duration of antibiotic treatment was 3-5 days. The NG group (n=29) included children who were not treated with antibiotics. We collected a total of 57 stool specimens. These specimens were subsequently analyzed via 16S rRNA gene sequencing. Continuous nonparametric data are represented as medians and were analyzed using the Wilcoxon rank-sum test. Results: Diversity analysis revealed a significant increase in the mean abundance but a significant decrease in diversity and a significant change in the composition of the intestinal flora in children after antibiotic treatment. At the phylum level, the intestinal flora of children consisted mainly of Bacteroidetes, Firmicutes, Proteobacteria, Verrucomicrobia, Actinobacteria, and Fusobacteria. At the genus level, antibiotic treatment significantly inhibited 33 groups of intestinal flora, such as Prevotella, while substantially increasing the number of 13 groups of intestinal flora, such as Megamonas and Enterococcus. In terms of metabolic function, protein modification, cofactors, prosthetic groups, electron carriers, vitamin biosynthesis, nucleic acid processing, secondary metabolite biosynthesis, and aldehyde degradation were significantly decreased. In contrast, the carbohydrate degradation and pentose phosphate pathway functions increased considerably after antibiotic treatment. Conclusions: Antibiotics have a significant impact on the composition and diversity of the intestinal flora of children. Antibiotics inhibited the growth of some colonizing flora, leading to an overgrowth of opportunistic pathogenic bacteria, which resulted in significant changes in some metabolic functions. Moreover, we identified a series of flora with considerable variability at the genus level, and these alterations in the intestinal flora could provide an additional basis for the diagnosis and treatment of antibiotic-associated diseases.