Burne R A
1 Department of Oral Biology, University of Florida, Gainesville, FL, USA.
Adv Dent Res. 2018 Feb;29(1):66-70. doi: 10.1177/0022034517735293.
Technological advances in DNA sequencing have provided unprecedented insights into the composition of the oral microbiome in health and disease, and RNA-sequencing and metabolomics-related technologies are beginning to yield information on the activities of these organisms. Importantly, progress in this area has brought the scientific community closer to an understanding of what constitutes a health-associated microbiome and is supporting the notion that the microbiota in healthy sites assumes an active role in promoting health and suppressing the acquisition, persistence, and activities of overt and opportunistic pathogens. It is also becoming clear that a significant impediment to developing a conclusive body of evidence that defines a healthy microbiome and the mechanisms by which beneficial bacteria promote health is that an inherent characteristic of the most abundant members of the oral flora, those that potentially play the greatest roles in health and disease, is intraspecies genomic diversity. In particular, individual isolates of abundant commensal and pathogenic streptococci show tremendous variability in gene content, and this variability manifests in tremendous phenotypic heterogeneity. Analysis of the consequences of this diversity has been complicated by the exquisite sensitivity these bacteria have evolved to environmental inputs, inducing rapid and substantial fluctuations in behaviors, and often only within subpopulations of the organisms. Thus, the conditions under which the oral microbiota is studied can produce widely different results within and between species. Fortunately, continually diminishing costs and ongoing refinements in sequencing and metabolomics are making it practical to study the oral microbiome at a level that will create a sufficiently robust understanding of the functions of individual organisms and reveal the complex interrelationships of these microbes ("the known unknowns") in a way that researchers will be able to engage in the rational design of reliable and economical risk assessments and preventive therapies.
DNA测序技术的进步为我们深入了解健康与疾病状态下口腔微生物群的组成提供了前所未有的视角，而RNA测序和代谢组学相关技术也开始提供有关这些微生物活动的信息。重要的是，该领域的进展使科学界更接近于理解构成健康相关微生物群的因素，并支持这样一种观点，即健康部位的微生物群在促进健康以及抑制显性和机会性病原体的获得、持续存在和活动方面发挥着积极作用。同样越来越清楚的是，要形成确凿的证据来界定健康微生物群以及有益细菌促进健康的机制，一个重大障碍在于口腔菌群中最丰富的成员（那些可能在健康和疾病中发挥最大作用的成员）的一个固有特征，即种内基因组多样性。特别是，大量共生和致病链球菌的单个分离株在基因含量上表现出极大的变异性，这种变异性表现为巨大的表型异质性。这些细菌对环境输入的高度敏感性使得对这种多样性后果的分析变得复杂，这种敏感性会导致行为的快速和大幅波动，而且往往只在微生物的亚群中出现。因此，研究口腔微生物群的条件可能在种内和种间产生截然不同的结果。幸运的是，测序和代谢组学成本的持续降低以及技术的不断改进，使得在能够充分深入了解个体微生物功能并揭示这些微生物复杂的相互关系（“已知的未知因素”）的层面上研究口腔微生物群变得切实可行，从而使研究人员能够进行可靠且经济的风险评估和预防性治疗的合理设计。
