[Study on the characteristics and differences of intestinal microbiota in children with allergic diseases].

Species richness was significantly higher in the allergic disease group compared to healthy controls.

• Chao1 index: Group A: 955.2±226.1, Group H: 762.3±260.9 (W=5664, P<0.0001)
• 214 children with allergic diseases and 93 healthy controls were included in the study
• Fecal samples were analyzed using metagenomic sequencing technology
• The number of species annotated at the genus level showed a gradually increasing trend with age

Significant differences in β-diversity were found between the 1-3 year old allergic disease group and healthy controls, and among disease subtypes in the ≥3 year old group.

• β-diversity difference between group A2 and H2: R=0.045, P=0.018
• β-diversity difference among AR, AD-AR, and AR-AS subgroups in A3: R=0.044, P=0.011
• No significant β-diversity differences were reported for the 0-1 year old group

At the species level, the allergic disease group was enriched with Bifidobacterium, Enterococcus, Escherichia, Mediterraneibacter, and Blautia, while the control group was mainly enriched with Bifidobacterium alone.

• Bifidobacterium was the dominant species in infancy in both groups
• Bifidobacterium relative abundance was consistently lower in the allergic disease group than in healthy controls across all age groups
• The allergic disease group showed enrichment of multiple additional genera beyond Bifidobacterium compared to controls

In infants aged 0-1 years, Mediterraneibacter and Blautia were significantly more abundant in the allergic disease group than in healthy controls.

• Mediterraneibacter: A1: 5.2±9.4 vs H1: 0.9±2.1 (W=718, P=0.0008)
• Blautia: A1: 3.5±6.0 vs H1: 1.3±3.2 (W=701, P=0.0005)
• These differences were identified using metagenomic sequencing of fecal samples

In children aged 1-3 years, Bacteroides and Faecalibacterium were significantly more abundant in the allergic disease group than in healthy controls.

• Bacteroides: A2: 5.6±8.7 vs H2: 3.1±5.8 (W=456, P=0.0208)
• Faecalibacterium: A2: 2.6±2.8 vs H2: 1.2±1.9 (W=395, P=0.0028)

In the 1-3 year old clinical subtype analysis, Blautia and Fusicatenibacter were significantly elevated in allergic rhinitis children, while Escherichia was significantly elevated in atopic dermatitis children.

• Blautia relative abundance: AD: 8.0±7.9, AD-AR: 13.5±8.3, AR: 20.2±7.8 (H=9.3008, P=0.0096)
• Fusicatenibacter relative abundance: AD: 0.5±0.9, AD-AR: 1.2±1.6, AR: 2.2±2.4 (H=7.8783, P=0.0195)
• Escherichia relative abundance: AD: 3.3±4.3, AD-AR: 1.8±4.5, AR: 0.8±2.0 (H=9.4766, P=0.0088)

In children aged ≥3 years, Mediterraneibacter was significantly enriched in the allergic disease group, and Anaerostipes was significantly elevated in allergic rhinitis children.

• Mediterraneibacter: A3: 6.3±6.9 vs H3: 2.9±1.9 (W=571, P=0.0397)
• Anaerostipes relative abundance: AD-AR: 2.9±2.9, AR: 5.2±4.9, AR-AS: 3.2±3.5 (H=7.269, P=0.0264)

The study used a case-control design with age-matched groups, enrolling patients from March 2023 to June 2024.

• 214 children with allergic diseases (Group A) and 93 healthy controls (Group H) were included
• Subjects were grouped into 0-1 year old (A1/H1), 1-3 year old (A2/H2), and ≥3 year old (A3/H3) age groups
• Within A1: food allergy without atopic dermatitis (F1) and food allergy with atopic dermatitis (F2); within A2: AD, AR, and AD-AR; within A3: AR, AD-AR, and AR with asthma (AS)
• All fecal samples were analyzed using metagenomic sequencing technology