Human Milk Oligosaccharides Reduce Murine Group BStreptococcusVaginal Colonization with Minimal Impact on the Vaginal Microbiota

Abstract

During pregnancy, GBS ascension into the uterus can cause fetal infection or preterm birth. In addition, GBS exposure during labor creates a risk of serious disease in the vulnerable newborn and mother postpartum.

Interrelated Effects of Zinc Deficiency and the Microbiome on Group B Streptococcal Vaginal Colonization

“…However, we identified a significant difference in the detection of unclassified Streptococcus between mice fed a control or zinc-deficient diet (analysis of composition of microbiomes [ANCOM] W = 112), although this difference did not persist after the introduction of GBS. We next assessed murine community state types (mCST) using previously described mCST I-VI groupings ( 16 , 17 ). In contrast to what was observed previously for mCSTs in C57BL/6 mice, we observed 56% of our naive CD-1 outbred mice (18/32), prior to the introduction of GBS, to have a vaginal community dominated by Enterobacteriaceae , which we have named here as mCST VII ( Fig.…”

Human Milk Oligosaccharides versus Streptococcus: How a Human-Made Natural Product Protects Us from Pathogens

“…They further characterized a putative GBS glycosyltransferase previously identified to be responsible for susceptibility to HMOs ( 10 ) and found that disruption of this system did not affect GBS in vitro adherence or biofilm formation, murine vaginal colonization, or susceptibility to antibiotics and other stressors. Also, they found that concentrations of pHMOs similar to those found in colostrum and human milk inhibited growth of both wild-type GBS and the HMO-resistant mutant, though to a lesser extent ( 14 ). The data presented nicely show that anti-GBS activity by HMOs significantly reduced GBS vaginal carriage without compromising the vaginal microbiota, and that the mechanism of HMO-mediated inhibition is distinct from previously published mechanisms observed in vitro .…”

“…In their recent publication, Mejia et al ( 14 ) use an in vivo model of murine vaginal colonization to address the impact of HMO treatment on GBS burden and endogenous vaginal microbiota. By coupling the GBS vaginal colonization model with 16S sequencing, the authors found that mice treated with pooled HMOs (pHMOs) before and during infection with GBS had significantly lower GBS burden in the vagina than mock treated groups ( 14 ). Importantly, this was achieved without affecting the overall community structure of the vaginal microbiota.…”

Human Milk Oligosaccharides as Potential Antibiofilm Agents: A Review

“…Akkermansia increases the secretion of mucin which reduces the colonization of harmful bacteria [ 78 ]. In 2022, an in vivo study by Kathryn and group demonstrated the protective activity of pooled HMOs against Group B Streptococcus (GBS) colonization in the vagina without altering the vaginal flora [ 79 ].…”

“…Several in vivo and in vitro studies have displayed compromised GBS colonization in the vagina without affecting the pre-existing vaginal microbiome. This can evolve as a promising preventive therapy against vaginosis [ 79 ]. Studies revealed that the acidic fraction of HMOs effectively alters the expression of genes responsible for the arrangement of surface receptors, which affects pathogen binding.…”