It is well known that the mite Leptotrombidium scutellare carries the pathogen of scrub typhus, Orientia tsutsugamushi. However, our understanding of other bacterial endosymbionts of mites is limited. This study investigated the diversity of the obligate intracellular bacteria carried by L. scutellare using 16S rRNA gene amplicon analysis with next-generation sequencing. The results showed that the detected bacteria were classified into the genera Rickettsia, Wolbachia, and Rickettsiella and an unknown genus of the order Rickettsiales. For further classification of the detected bacteria, a representative read that was most closely related to the assigned taxonomic classification was subjected to homology search and phylogenic analysis. The results showed that some bacteria of the genus Rickettsia were identical or very close to the human pathogens Rickettsia akari, Rickettsia aeschlimannii, Rickettsia felis, and Rickettsia australis. The genetic distance between the genus Wolbachia bacteria in the present study and in previous reports is highly indicative that the bacteria in the present study can be classified as a new taxon of Wolbachia. This study detected obligate intracellular bacteria from unfed mites; thus, the mites did not acquire bacteria from infected animals or any other infectious sources. Finally, the present study demonstrated that various and novel bacterial endosymbionts of mites, in addition to O. tsutsugamushi, might uniquely evolve with the host mites throughout overlapping generations of the mite life cycle. The roles of the bacteria in mites and their pathogenicity should be further examined in studies based on bacterial isolation.

中文翻译：

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未进食的小角L虫幼虫中专性的细胞内细菌多样性突出了螨的新型细菌内共生菌。

众所周知，螨小角豆科黄cut带有灌木斑疹伤寒东方Or虫病。但是，我们对螨的其他细菌内共生体的了解是有限的。这项研究使用16S rRNA基因扩增子分析和下一代测序技术研究了盾片菌携带的专性细胞内细菌的多样性。结果表明，检测到的细菌分为立克次氏菌，沃尔巴克氏菌和立克次氏菌属，以及立克次氏体的未知属。为了进一步对检测到的细菌进行分类，对与指定分类标准最密切相关的代表性读物进行了同源搜索和系统发育分析。结果表明，立克次氏菌属的某些细菌与人类病原体立克次氏体，立克次体立克次体，猫立克次体和澳大利亚立克次体相同或非常接近。本研究和以前的报道中的Wolbachia细菌属之间的遗传距离高度表明，本研究中的细菌可以被分类为Wolbachia的新分类群。这项研究从未进食的螨虫中发现了专性的细胞内细菌。因此，螨虫没有从被感染的动物或任何其他传染源获得细菌。最后，本研究表明，除O虫以外，各种新颖的螨虫细菌内共生菌还可能在螨虫生命周期的整个重叠世代中与宿主螨虫一起独特地进化。