Data from: Concordance of bacterial communities of two tick species and blood of their shared rodent host

Most macro-organisms house diverse microbial communities and with increasing use of high-throughput sequencing our knowledge of their microbiomes is growing. Of particular interest are disease vectors whose associations with microbes can have significant influences on pathogen transmission and vector competence. We investigated the bacterial community composition and diversity of two tick species, Dermacentor variabilis and Ixodes scapularis, and blood of a shared rodent host, Peromyscus leucopus. The 16S rRNA gene was amplified from genomic DNA from field-collected tick and rodent blood samples and 454 pyrosequencing was used to evaluate their bacterial communities. After quality control, over 300,000 sequences were obtained and 130 Operational Taxonomic Units (OTUs, clustered at 97% similarity) were searched against SILVA to find the best taxonomic match. The most abundant OTUs from each sample type were tick species-specific endosymbionts and Bartonella, a common vector-borne bacterium of rodents. There was considerable overlap in the distribution of OTUs but nonmetric multi-dimensional scaling and C-score analyses indicated that communities from each sample type were significantly different and highly structured. Surprisingly, Bartonella, most commonly described as a flea-vectored bacterium, was present in larvae and nymphs of both tick species, as well as rodent blood. The overlap of many bacterial taxa between tick species and shared hosts may create conditions for movement to new vector species and the evolution of new pathogenic strains.

绝大多数大型生物均携带有多样的微生物群落（microbiome），随着高通量测序技术的应用日益普及，学界对其微生物组的认知也在不断深化。其中尤为受关注的是疾病媒介生物，它们与微生物的共生关系可对病原体传播及媒介效能（vector competence）产生显著影响。本研究针对两种蜱类——变异革蜱（Dermacentor variabilis）与肩突硬蜱（Ixodes scapularis），以及它们共同的啮齿类宿主白足鼠（Peromyscus leucopus）的血液样本，开展了细菌群落组成与多样性分析。研究人员从野外采集的蜱类及啮齿类血液样本的基因组DNA中扩增16S rRNA基因（16S rRNA gene），并通过454焦磷酸测序技术对其细菌群落进行解析。质控完成后，共获得超过30万条序列；针对以97%相似度聚类得到的130个操作分类单元（Operational Taxonomic Units，OTUs），通过与SILVA数据库比对以获取最佳分类学匹配结果。各样本类型中丰度最高的OTUs均为蜱类物种特异性内共生菌，以及巴尔通体属（Bartonella）——一类常见的啮齿类虫媒细菌。尽管不同样本间的OTU分布存在较多重叠，但非度量多维尺度分析（nonmetric multi-dimensional scaling，NMDS）与C-score分析结果显示，各样本类型的细菌群落存在显著差异且结构高度规整。令人意外的是，通常被认为是跳蚤传播的巴尔通体属细菌，不仅在啮齿类血液中存在，还检出于两种蜱类的幼虫与若虫阶段。蜱类与共同宿主间存在大量细菌类群的重叠，这可能为病原体向新的媒介物种转移以及新型致病菌株的演化创造了条件。