Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
Institute of Agrobiotechnology and Molecular Biology, IABiMo, INTA-CONICET, Buenos Aires, Argentina.
Dev Comp Immunol. 2020 May;106:103606. doi: 10.1016/j.dci.2019.103606. Epub 2020 Jan 2.
Although the ticks Amblyomma sculptum and Amblyomma aureolatum are important vectors of Rickettsia rickettsii, causative agent of the life-threatening Rocky Mountain spotted fever, A. aureolatum is considerably more susceptible to infection than A. sculptum. As the microbiota can interfere with the colonization of arthropod midgut (MG) by pathogens, in the current study we analyzed the MG microbiota of both tick species. Our results revealed that the MG of A. aureolatum harbors a prominent microbiota, while A. sculptum does not. Remarkably, a significant reduction of the bacterial load was recorded in R. rickettsii-infected A. aureolatum. In addition, the taxonomy analysis of the MG bacterial community of A. aureolatum revealed a dominance of the genus Francisella, suggesting an endosymbiosis. This study is the first step in getting insights into the mechanisms underlying the interactions among Amblyomma species, their microbiota and R. rickettsii. Additional studies to better understand these mechanisms are required and may help the development of novel alternatives to block rickettsial transmission.
虽然硬蜱属的 Amblyomma sculptum 和 Amblyomma aureolatum 是携带导致威胁生命的落矶山斑点热的立克次氏体（Rickettsia rickettsii）的重要媒介，但 A. aureolatum 比 A. sculptum 更容易受到感染。由于微生物群可以干扰节肢动物中肠 (MG) 被病原体的定植，在当前的研究中，我们分析了这两种蜱的 MG 微生物群。我们的结果表明，A. aureolatum 的 MG 中存在着突出的微生物群，而 A. sculptum 则没有。值得注意的是，在感染了 R. rickettsii 的 A. aureolatum 中，细菌负荷显著减少。此外，对 A. aureolatum MG 细菌群落的分类分析表明，弗朗西斯菌属占主导地位，提示存在内共生关系。这项研究是深入了解 Amblyomma 物种、它们的微生物群和 R. rickettsii 之间相互作用机制的第一步。需要进一步的研究来更好地理解这些机制，这可能有助于开发阻止立克次氏体传播的新替代方法。
