Probiotic supplementation modulates the gut microbiome and improves clinical outcomes in pediatric refractory asthma.

BACKGROUND

Refractory asthma in children remains a clinical challenge despite conventional therapies, with emerging evidence linking gut microbiome dysbiosis to persistent inflammation via the gut-lung axis. This study investigated whether multi-strain probiotic supplementation could improve asthma control and restore microbial balance when added to standard treatment.

METHODS

This prospective randomized controlled trial enrolled 88 children aged 4-8 years with refractory asthma. Participants were allocated into two groups (n = 44 each): a conventional treatment group (bronchodilators and glucocorticoids) and a combination treatment group, which received conventional therapy plus a multi-strain probiotic (Bifidobacterium, Lactobacillus acidophilus, Streptococcus thermophilus) for 4 months. Primary outcomes were asthma control level, Asthma Control Test (ACT) scores, and pulmonary function (FEV₁, FVC, PEF). Secondary outcomes included gut microbiota changes, assessed by 16S rRNA gene sequencing.

RESULTS

Combination therapy achieved complete asthma control in 68.18% of patients versus 36.36% with conventional therapy (Z = 2.415, p < 0.05). Post-treatment ACT scores were higher in the combination group (22.45 ± 1.20 vs. 19.78 ± 1.45; p < 0.05), with superior improvements in FEV1 (2.65 ± 0.10 L vs. 2.30 ± 0.08 L; p < 0.001), FVC (3.10 ± 0.18 L vs. 2.80 ± 0.15 L; p < 0.001), and PEF (4.00 ± 0.25 L/s vs. 3.50 ± 0.20 L/s; p < 0.001). Symptoms resolved faster with combination therapy (e.g., cough: 5.60 ± 1.50 vs. 10.45 ± 2.30 days; p < 0.05). Microbiome analysis showed increased alpha diversity (e.g., Shannon index: p < 0.05) and beneficial shifts in the combination group, including higher Bifidobacterium (25.00 ± 15.31% vs. 0.98 ± 1.92%; p < 0.001) and reduced Bacteroides, with distinct beta diversity clustering (PERMANOVA p < 0.05).

CONCLUSION

Adjunctive multi-strain probiotics enhance clinical outcomes and gut microbiome health in pediatric refractory asthma, supporting microbiome-targeted therapies via the gut-lung axis. Larger, double-blind randomized controlled trials are warranted to confirm long-term benefits.