The entero–mammary pathway is a specialized route that selectively translocates bacteria to the newborn’s gut, playing a crucial role in neonatal development. Previous studies report shared bacterial and archaeal taxa between human milk and neonatal intestine. However, the functional implications for neonatal development are not fully understood due to limited evidence. This study aimed to identify and characterize the microbiota and metabolome of human milk, mother, and infant stool samples using high-throughput DNA sequencing and FT-ICR MS methodology at delivery and 4 months post-partum. Twenty-one mothers and twenty-five infants were included in this study. Our results on bacterial composition suggest vertical transmission of bacteria through breastfeeding, with major changes occurring during the first 4 months of life. Metabolite chemical characterization sheds light on the growing complexity of the metabolites. Further data integration and network analysis disclosed the interactions between different bacteria and metabolites in the biological system as well as possible unknown pathways. Our findings suggest a shared bacteriome in breastfed mother–neonate pairs, influenced by maternal lifestyle and delivery conditions, serving as probiotic agents in infants for their healthy development. Also, the presence of food biomarkers in infants suggests their origin from breast milk, implying selective vertical transmission of these features.

Recurrent vulvovaginal candidiasis (RVVC) is a common condition that affects women of reproductive age. The etiology of RVVC remains largely unknown, but it is believed to be associated with changes in vaginal microbiota composition. This study investigates the vaginal microbiota in 57 women with RVVC and 38 healthy controls. Bacterial DNA was analyzed using high-throughput 16S rRNA gene sequencing, and Candida and Saccharomyces species were determined by PCR. RVVC cases had a higher prevalence of Nakaseomyses glabratus (former Candida glabrata) compared to controls. Alpha diversity metrics were similar between groups, but beta diversity analysis revealed significant differences in vaginal microbiota composition. The Firmicutes abundance was altered in RVVC cases, with genus Bifidobacterium and phylum Actinobacteriota being more abundant than in the controls. At the genus level, Lactobacillus dominated controls using antibiotics, while Bifidobacterium was higher in cases with no antibiotic intake. Our study provides evidence that Nakaseomyses glabratus (former Candida glabrata) is a significant pathogen in RVVC, while Candida albicans was more prevalent in healthy women. The vaginal microbiota composition differs significantly between the two groups, with distinct patterns of bacterial abundance and changes in Firmicutes abundance.