Simser Jason A, Palmer Ann T, Fingerle Volker, Wilske Bettina, Kurtti Timothy J, Munderloh Ulrike G
Department of Entomology, University of Minnesota, St. Paul, Minnesota 55108, USA.
Appl Environ Microbiol. 2002 Sep;68(9):4559-66. doi: 10.1128/AEM.68.9.4559-4566.2002.
We describe the isolation and characterization of Rickettsia monacensis sp. nov. (type strain, IrR/Munich(T)) from an Ixodes ricinus tick collected in a city park, the English Garden in Munich, Germany. Rickettsiae were propagated in vitro with Ixodes scapularis cell line ISE6. BLAST analysis of the 16S rRNA, the citrate synthase, and the partial 190-kDa rickettsial outer membrane protein A (rOmpA) gene sequences demonstrated that the isolate was a spotted fever group (SFG) rickettsia closely related to several yet-to-be-cultivated rickettsiae associated with I. ricinus. Phylogenetic analysis of partial rompA sequences demonstrated that the isolate was genotypically different from other validated species of SFG rickettsiae. R. monacensis also replicated in cell lines derived from the ticks I. ricinus (IRE11) and Dermacentor andersoni (DAE100) and in the mammalian cell lines L-929 and Vero, causing cell lysis. Transmission electron microscopy of infected ISE6 and Vero cells showed rickettsiae within the cytoplasm, pseudopodia, nuclei, and vacuoles. Hamsters inoculated with R. monacensis had immunoglobulin G antibody titers as high as 1:16,384, as determined by indirect immunofluorescence assay. Western blot analyses demonstrated that the hamster sera cross-reacted with peptides from other phylogenetically distinct rickettsiae, including rOmpA. R. monacensis induced actin tails in both tick and mammalian cells similar to those reported for R. rickettsii. R. monacensis joins a growing list of SFG rickettsiae that colonize ticks but whose infectivity and pathogenicity for vertebrates are unknown.
我们描述了从德国慕尼黑英国花园城市公园采集的蓖麻硬蜱中分离并鉴定出的新种蒙纳西斯立克次体（Rickettsia monacensis sp. nov.）（模式菌株，IrR/慕尼黑(T)）。立克次体在体外通过肩突硬蜱细胞系ISE6进行培养。对16S rRNA、柠檬酸合酶和部分190 kDa立克次体外膜蛋白A（rOmpA）基因序列进行BLAST分析表明，该分离株是斑点热群（SFG）立克次体，与几种尚未培养的与蓖麻硬蜱相关的立克次体密切相关。对部分rompA序列进行系统发育分析表明，该分离株在基因型上与其他已验证的SFG立克次体物种不同。蒙纳西斯立克次体也能在源自蓖麻硬蜱（IRE11）和安氏革蜱（DAE100）的细胞系以及哺乳动物细胞系L-929和Vero中复制，导致细胞裂解。对感染的ISE6和Vero细胞进行透射电子显微镜观察显示，细胞质、伪足、细胞核和液泡内存在立克次体。通过间接免疫荧光测定法确定，接种蒙纳西斯立克次体的仓鼠免疫球蛋白G抗体效价高达1:16,384。蛋白质印迹分析表明，仓鼠血清与来自其他系统发育上不同的立克次体的肽段发生交叉反应，包括rOmpA。蒙纳西斯立克次体在蜱细胞和哺乳动物细胞中均诱导形成肌动蛋白尾，类似于报道的立氏立克次体（R. rickettsii）。蒙纳西斯立克次体加入了越来越多的SFG立克次体名单，这些立克次体寄生于蜱，但对脊椎动物的感染性和致病性尚不清楚。
