Le Bras Charles, Mouchard Alizé, Rault Lucie, Cochet Marie-Françoise, Ménard Olivia, Jacquet Nolwenn, Chuat Victoria, Valence Florence, Le Loir Yves, Bellanger Amandine, Deglaire Amélie, Le Huërou-Luron Isabelle, Even Sergine
STLO, INRAE, Institut Agro Rennes Angers, Rennes, France.
Institut NuMeCan, INRAE, INSERM, Université de Rennes, Saint Gilles, France.
Sci Rep. 2025 Mar 31;15(1):10985. doi: 10.1038/s41598-025-95668-6.
Human milk (HM) microbiota is increasingly studied for its potential health benefits. However, the physiological state of HM bacteria and consequently their effects on gut homeostasis remain a question. This study investigated the physiological state of the HM microbiota by characterizing its cultivable fraction as it might be at the point of ingestion and assessing the effects of digestion, in the specific context of the immature infant digestive tract, on the cultivability and immunomodulatory properties of six HM strains representative of prevalent genera in HM. Twenty-eight HM samples were analysed by 16 S metabarcoding either directly on raw milk (raw milk microbiota, RM) or on the complete cultivable fraction obtained from seven non-selective media (cultivable milk microbiota, CM). This approach enabled a more in-depth investigation of CM than conventional methods based on the individual sequencing of a subset of isolates and resulted in a moderate gain in diversity within each HM sample. It confirmed that diversity was lower in CM than in RM, with ~ 7 versus 69 genera per sample in CM and RM respectively, and an under-representation of strictly anaerobic genera in CM. In vitro infant gastrointestinal digestion resulted in overall good survival of the 6 HM strains but partial or complete loss of their immunomodulatory properties on the monocyte THP1 cell line, except for a Staphylococcus epidermidis strain that gained immunomodulatory potential. These results highlight the potential of HM bacteria to survive during the infant gastrointestinal digestion and interact with the intestinal epithelium and immune system, as well as the importance of considering the digestion process when evaluating host-bacteria interactions.
人乳(HM)微生物群因其潜在的健康益处而受到越来越多的研究。然而,HM细菌的生理状态及其对肠道稳态的影响仍是一个问题。本研究通过表征其可培养部分(可能在摄入时的状态)来研究HM微生物群的生理状态,并在未成熟婴儿消化道的特定背景下,评估消化对六种代表HM中常见属的HM菌株的可培养性和免疫调节特性的影响。通过16S元条形码技术直接对原奶(原奶微生物群,RM)或从七种非选择性培养基获得的完整可培养部分(可培养奶微生物群,CM)分析了28份HM样本。与基于部分分离株个体测序的传统方法相比,这种方法能够更深入地研究CM,并在每个HM样本中适度增加了多样性。它证实了CM中的多样性低于RM,CM和RM中每个样本分别约有7个属和69个属,并且CM中严格厌氧属的代表性不足。体外婴儿胃肠道消化导致6种HM菌株总体存活率良好,但除了一株获得免疫调节潜力的表皮葡萄球菌菌株外,它们对单核细胞THP1细胞系的免疫调节特性部分或完全丧失。这些结果突出了HM细菌在婴儿胃肠道消化过程中存活并与肠上皮和免疫系统相互作用的潜力,以及在评估宿主-细菌相互作用时考虑消化过程的重要性。