母乳中含有丰富的微生物群

2013年1月5日讯 /生物谷BIOON/ --近日，西班牙研究人员发现了新生儿主要营养来源的母乳中的细菌微生物比原先认知的更具多样性。这项研究揭示了一个更大的微生物多样性：有超过700个微生物。 母亲母乳中的细菌种类是决定其在新生婴儿中如何发展的因素之一。然而，该组合物和这些细菌的生物学作用在婴儿中是未知的。一组西班牙科学家采用以大规模DNA测序基础的新技术，确定一系列母乳中所含的细菌微生物。他们研究产前和产后母乳的变量影响牛奶的微生物丰富性。 初乳是分娩后乳腺腺体的分泌物。在这种液体样本中，超过700种微生物被发现，这是比原先预计还多的微生物群。该成果已发表在American Journal of Clinical Nutrition杂志上。 研究主要利用焦磷酸测序技术（大规模DNA序列测定技术）测定初乳样品多样性。初乳样品中最常见的细菌属为魏斯氏菌属（Weissella）, 明串珠菌属(Leuconostoc), 葡萄球菌（Staphylococcus）合乳球菌属(Lactococcus)。 在母乳喂养的第一和第六个月，研究人员对婴儿口腔内的细菌进行了观察，如Veillonella(韦荣球菌属), 纤毛菌属(Leptotrichia) 和普氏菌属（Prevotella）。我们还不能够确定是否这些细菌是原先存在于宝宝嘴中，还是吃母乳中获得的。 研究人员是现在的工作是确定如果这些微生物的作用是代谢（它有助于在吃母乳的婴儿过渡到消化牛奶阶段）或是免疫（有助于区分有益物质或者外来生物）。对于作者，结果打开了新的大门帮助设计儿童营养战略，提高健康。 如果在这项研究中发现的母乳细菌对免疫系统的发展是很重要的，那么婴幼儿配方奶粉引发过敏，哮喘和自身免疫性疾病风险将大大降低。（生物谷：Bioon.com） doi:10.3945/ajcn.112.037382 PMC: PMID: The human milk microbiome changes over lactation and is shaped by maternal weight and mode of delivery Cabrera-Rubio R, et al BACKGROUND: Breast milk is recognized as the most important postpartum element in metabolic and immunologic programming of health of neonates. The factors influencing the milk microbiome and the potential impact of microbes on infant health have not yet been uncovered. OBJECTIVE: Our objective was to identify pre- and postnatal factors that can potentially influence the bacterial communities inhabiting human milk. DESIGN: We characterized the milk microbial community at 3 different time points by pyrosequencing and quantitative polymerase chain reaction in mothers (n = 18) who varied in BMI, weight gain, and mode of delivery. RESULTS: We found that the human milk microbiome changes over lactation. Weisella, Leuconostoc, Staphylococcus, Streptococcus, and Lactococcus were predominant in colostrum samples, whereas in 1- and 6-mo milk samples the typical inhabitants of the oral cavity (eg, Veillonella, Leptotrichia, and Prevotella) increased significantly. Milk from obese mothers tended to contain a different and less diverse bacterial community compared with milk from normal-weight mothers. Milk samples from elective but not from nonelective mothers who underwent cesarean delivery contained a different bacterial community than did milk samples from individuals giving birth by vaginal delivery, suggesting that it is not the operation per se but rather the absence of physiological stress or hormonal signals that could influence the microbial transmission process to milk. CONCLUSIONS: Our results indicate that milk bacteria are not contaminants and suggest that the milk microbiome is influenced by several factors that significantly skew its composition. Because bacteria present in breast milk are among the very first microbes entering the human body, our data emphasize the necessity to understand the biological role that the milk microbiome could potentially play for human health.