Dual-strain probiotics Bifidobacterium bifidum and Lactobacillus acidophilus reverse gut dysbiosis in preterm neonates: a randomized controlled trial.

Background: Preterm neonates exhibit gut dysbiosis, characterized by increased numbers of pathogenic bacteria and decreased Bifidobacterium and Lactobacillus levels. Supplementation with the probiotic Bifidobacterium bifidum/Lactobacillus acidophilus (BB/LA) may reverse gut dysbiosis.

Purpose: To study the effects of BB/LA on the gut microbiota of preterm neonates.

Methods: We enrolled neonates born between July 2022 and September 2023 with a gestational age of <33 weeks or birth weight of <1,500 g. After randomization into probiotic (PG) and control (CG) groups, stool samples were collected at 3 time points: birth (V1), 35 weeks' postmenstrual age (PMA) (V2), and 4 months of age (V3). BB/LA was administered to the PG until PMA 35 weeks. All neonates received a feeding protocol similar to that of predominant breast milk. Stool samples were stored at -80°C, a DNA extraction performed, and 16S rRNA gene sequencing used to define alpha and beta diversities and the relative abundances of the bacteria. Baseline characteristics and clinical outcomes were collected.

Results: We analyzed 68 neonates (33 in the PG, 35 in the CG). The alpha diversities did not differ significantly between the groups at any time point. At V1, beta diversity was not significantly different between the 2 groups. After BB/LA supplementation (V2), beta diversity was significantly greater in the PG versus CG (P=0.004). The relative abundances of Bifidobacterium and Lactobacillus were higher in the PG (both P<0.001), whereas that of Clostridium senso stricto 1 was higher in the CG (P=0.017). Growth parameters, necrotizing enterocolitis, and mortality rate did not differ between groups. No adverse events were observed.

Conclusion: BB/LA led to healthier gut microbiota in preterm neonates as demonstrated by a reversal of gut dysbiosis characterized by increased beta diversity, increased the relative abundances of Bifidobacterium and Lactobacillus, and decreased the relative abundance of Clostridium senso stricto 1.