[Characteristics of intestinal microbiota in the acute phase of Kawasaki disease in infants and children].

Objectives: To study the composition, abundance, and functional profiles of the intestinal microbiota in infants and young children with Kawasaki disease (KD) during the acute phase, and to explore the potential role of intestinal microbiota in the pathogenesis of KD.

Methods: Six children aged 0-3 years with acute KD admitted to the Department of Cardiology, Children's Hospital Affiliated to Capital Institute of Pediatrics from July to October 2021 were prospectively included as the KD group. Six age- and sex-matched healthy children who underwent physical examinations at the hospital during the same period were selected as the healthy control group. Metagenomics sequencing was used to detect and compare the differences in the microflora structure and functional profiles of fecal samples between the two groups.

Results: There were significant differences in the structural composition and diversity of intestinal microbiota between the two groups (<0.05). Compared with the healthy control group, the abundance of _ (family and genus ), _, _, and _ was significantly higher in the intestinal microbiota in the KD group (LDA>2.0, <0.05). The steroid degradation and apoptosis pathways were significantly upregulated in the KD group compared with the healthy control group, while the Bacterial_secretion_system, Sulfur_metabolism, Butanoate_metabolism, Benzoate_degradation, β-alanine metabolism, and α-linolenic acid pathways were significantly downregulated (|LDA|>2, <0.05).

Conclusions: There are significant differences in the structure and diversity of intestinal microbiota between children aged 0-3 years with acute KD and healthy children, suggesting that disturbances in intestinal microbiota occur during the acute phase of KD. In particular, _, _, and _ may be involved in the pathogenesis of KD through steroid degradation and apoptosis pathways.