Pets. House Dust and GI Microbiota and Infant Allergy

项目1的总体假设是，养宠物与室内灰尘中更广泛的细菌暴露有关，这些暴露对婴儿胃肠道微生物群的细菌群落组成（BCC）、免疫反应的成熟以及随后的过敏和过敏性哮喘的发展产生深远影响。因此，本项目提出了两项基于人群的研究和一项纵向小组研究，以阐明可能解释在婴儿时期接触家庭宠物对婴儿特应性和高总IgE发展的保护作用的机制。我们建议使用一种先进的、高灵敏度和半定量的细菌检测方法——G3 PhyloChip。该方法为复杂微生物群落的详细，高分辨率分析提供了前所未有的能力，可以平行检测房屋灰尘和婴儿粪便样本中常见和不常见的组合成员。对于目标1和2，我们建议检查已经收集和储存的样本，这些样本来自一个大型的、仔细表征的、种族和社会经济多样化的儿童队列（WHEALS队列）。在目的1中，我们建议使用一种创新的病例队列设计来比较2岁时成为特应性反应的婴儿样本与随机选择的子队列（作为对照组）的样本。利用Aim 2中的亚队列，我们将确定室内灰尘和婴儿粪便的细菌群落组成是否受到宠物饲养的影响，以及以何种方式受到影响，以及它们是否相互关联。对细菌或细菌群落的研究将通过一项小型前瞻性小组研究（Aim 3）来实现，该研究旨在分析在有孩子但以前没有宠物的家庭中，在养狗的情况下，室内灰尘中微生物群落组成的变化。由于16S-rRNAPhyloChip提供了检测到的每个细菌分类群的相对丰度信息，我们的目标是通过统计分析，利用这种半定量数据来确定特定的细菌物种，这些细菌物种对防止特应性发育至关重要。

The overarching hypothesis of Project 1 is that pet ownership is associated with exposure to a wider diversity of bacteria in house dust, and that these exposures profoundly influence the bacterial community composition (BCC) of the infant gastrointestinal microbiome, maturation of immune responsiveness and subsequently, the development of allergy and allergic asthma. This Project thus proposes two population based studies and a longitudinal panel study to shed light upon mechanisms that may explain the observed protective effects of exposure to household pets during infancy against development of atopy and high total IgE in infancy. We propose to use an advanced, highly sensitive and semi-quantitative method for bacterial detection, the G3 PhyloChip. This method offers an unprecedented capacity for detailed, high-resolution profiling of complex microbial communities, detecting in parallel common and uncommon members of assemblages present in house dust and infant stool samples. For Aims 1 and 2, we propose to examine samples already collected and stored from a large, carefully characterized, racially and socio-economically diverse, cohort of children (the WHEALS cohort). In Aim 1 we propose using an innovative case-cohort design to compare samples from infants who became atopic at age 2 years versus samples from a randomly selected sub-cohort (serving as the control group). Using the sub-cohort in Aim 2, we will determine whether, and in what fashion, bacterial community composition of both house dust and infant stool are impacted by pet-keeping and if they are related to each other. The study of bacteria, or bacterial communities, identified as deriving from dog keeping will be enabled by a small prospective panel study proposed as Aim 3, to analyze the changes in microbial community composition of house dust in child-occupied but previously pet free households into which a dog is introduced. Because the 16S-rRNAPhyloChip provides information on relative abundance of every bacterial taxon detected, we aim, through statistical analyses, to take advantage of this semi-quantitative data to identify particular bacterial species as critically important in protection against atopy development.