Ticks are globally distributed arthropods and a public health concern due to the many human pathogens they carry and transmit, including the causative agent of Lyme disease, Borrelia burgdorferi. As tick species’ ranges increase, so do the number of reported tick related illnesses. The microbiome is a critical part of understanding arthropod biology, and the microbiome of pathogen vectors may provide critical insight into disease transmission and management. Yet we lack a comprehensive understanding of the microbiome of wild ticks, including what effect the presence of multiple tick-borne pathogens (TBPs) has on the microbiome. In this study we chose samples based on life stage (adult or nymph) and which TBPs were present. We used DNA from previously extracted Ixodes scapularis ticks that tested positive for zero, one, two or three common TBPs (B. burgdorferi, B. miyamotoi, Anaplasma phagocytophilum, Babesia microti). We produced 16S rRNA amplicon data for the whole tick microbiome and compared samples across TBPs status, single vs multiple coinfections, and life stages. Focusing on samples with a single TBP, we found no significant differences in microbiome diversity in ticks that were infected with B. burgdorferi and ticks with no TBPs. When comparing multiple TBPs, we found no significant difference in both alpha and beta diversity between ticks with a single TBP and ticks with multiple TBPs. Removal of TBPs from the microbiome did not alter alpha or beta diversity results. Life stage significantly correlated to variation in beta diversity and nymphs had higher alpha diversity than adult ticks. Rickettsia, a common tick endosymbiont, was the most abundant genus. This study confirms that the wild tick microbiome is highly influenced by life stage and much less by the presence of human pathogenic bacteria.

中文翻译：

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在提交进行诊断测试的蜱中，肩胛硬蜱微生物组与生命阶段相关，而不是与人类病原体的存在相关

蜱是全球分布的节肢动物，由于它们携带和传播许多人类病原体，包括莱姆病的病原体，伯氏疏螺旋体，这是一个公共卫生问题。随着蜱物种分布范围的增加，报告的蜱相关疾病的数量也在增加。微生物组是理解节肢动物生物学的关键部分，病原体载体的微生物组可以为疾病传播和管理提供重要的见解。然而，我们对野生蜱的微生物组缺乏全面的了解，包括多种蜱传病原体 (TBP) 的存在对微生物组的影响。在这项研究中，我们根据生命阶段（成虫或若虫）和存在哪些 TBP 来选择样本。我们使用了先前提取的肩胛硬蜱的 DNA，这些蜱的零、一、二或三种常见 TBP（B. burgdorferi, B. miyamotoi, Anaplasma phagocytophilum, Babesia microti)。我们为整个蜱微生物组生成了 16S rRNA 扩增子数据，并比较了 TBP 状态、单一与多重共感染和生命阶段的样本。关注具有单一 TBP 的样本，我们发现感染了伯氏疏螺旋体的蜱和没有 TBP 的蜱的微生物组多样性没有显着差异。在比较多个 TBP 时，我们发现具有单个 TBP 的蜱和具有多个 TBP 的蜱之间的 alpha 和 beta 多样性没有显着差异。从微生物组中去除 TBP 不会改变 alpha 或 beta 多样性结果。生命阶段与β多样性的变化显着相关，若虫比成年蜱具有更高的α多样性。立克次体是一种常见的蜱内共生体，是最丰富的属。