The Human Nasal Microbiota and <em>Staphylococcus aureus</em> Carriage

BackgroundColonization of humans with Staphylococcus aureus is a critical prerequisite of subsequent clinical infection of the skin, blood, lung, heart and other deep tissues. S. aureus persistently or intermittently colonizes the nares of ∼50% of healthy adults, whereas ∼50% of the general population is rarely or never colonized by this pathogen. Because microbial consortia within the nasal cavity may be an important determinant of S. aureus colonization we determined the composition and dynamics of the nasal microbiota and correlated specific microorganisms with S. aureus colonization. Methodology/Principal FindingsNasal specimens were collected longitudinally from five healthy adults and a cross-section of hospitalized patients (26 S. aureus carriers and 16 non-carriers). Culture-independent analysis of 16S rRNA sequences revealed that the nasal microbiota of healthy subjects consists primarily of members of the phylum Actinobacteria (e.g., Propionibacterium spp. and Corynebacterium spp.), with proportionally less representation of other phyla, including Firmicutes (e.g., Staphylococcus spp.) and Proteobacteria (e.g. Enterobacter spp). In contrast, inpatient nasal microbiotas were enriched in S. aureus or Staphylococcus epidermidis and diminished in several actinobacterial groups, most notably Propionibacterium acnes. Moreover, within the inpatient population S. aureus colonization was negatively correlated with the abundances of several microbial groups, including S. epidermidis (p = 0.004). Conclusions/SignificanceThe nares environment is colonized by a temporally stable microbiota that is distinct from other regions of the integument. Negative association between S. aureus, S. epidermidis, and other groups suggests microbial competition during colonization of the nares, a finding that could be exploited to limit S. aureus colonization.背景 人类定植金黄色葡萄球菌（Staphylococcus aureus）是随后引发皮肤、血液、肺、心脏及其他深部组织临床感染的关键先决条件。约50%的健康成人的鼻腔会持续或间歇性定植该菌，而约50%的普通人群极少或从未被此病原菌定植。由于鼻腔内的微生物群落可能是影响金黄色葡萄球菌定植的重要决定因素，本研究明确了鼻腔微生物组的组成与动态变化，并将特定微生物与金黄色葡萄球菌定植情况进行了关联分析。 方法/主要研究结果 本研究采集了5名健康成人的纵向随访鼻腔标本，以及一批住院患者的横断面鼻腔标本（其中26名为金黄色葡萄球菌定植者，16名为非定植者）。通过对16S核糖体RNA（16S rRNA）序列开展不依赖培养的分析发现，健康受试者的鼻腔微生物组主要由放线菌门（Actinobacteria）成员构成，例如丙酸杆菌属（Propionibacterium spp.）与棒状杆菌属（Corynebacterium spp.），其他菌门的占比相对较低，包括厚壁菌门（Firmicutes，如葡萄球菌属Staphylococcus spp.）与变形菌门（Proteobacteria，如肠杆菌属Enterobacter spp.）。与之相反，住院患者的鼻腔微生物组中，金黄色葡萄球菌或表皮葡萄球菌（Staphylococcus epidermidis）的丰度显著升高，而多个放线菌类群的丰度则出现下降，其中尤以痤疮丙酸杆菌（Propionibacterium acnes）最为明显。此外，在住院患者群体中，金黄色葡萄球菌定植情况与多个微生物类群的丰度呈负相关，其中包括表皮葡萄球菌（P=0.004）。 结论与意义 鼻腔环境定植着具有时间稳定性的微生物组，该微生物组与体表其他区域的微生物组存在显著差异。金黄色葡萄球菌、表皮葡萄球菌及其他类群之间的负相关关系提示，鼻腔定植过程中存在微生物竞争，这一发现可被用于开发限制金黄色葡萄球菌定植的干预策略。