Department of Biological Sciences, Old Dominion University, Norfolk, Virginia, 23529, USA.
Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, 30329, USA.
Int J Syst Evol Microbiol. 2021 Jul;71(7). doi: 10.1099/ijsem.0.004880.
A previously unrecognized species was isolated in 1976 from a pool of ticks collected in 1967 from Tillamook County, Oregon, USA. The isolate produced low fever and mild scrotal oedema following intraperitoneal injection into male guinea pigs (). Subsequent serotyping characterized this isolate as distinct from recognized typhus and spotted fever group species; nonetheless, the isolate remained unevaluated by molecular techniques and was not identified to species level for the subsequent 30 years. is the most frequently identified human-biting tick in the western United States, and as such, formal identification and characterization of this potentially pathogenic species is warranted. Whole-genome sequencing of the Tillamook isolate revealed a genome 1.43 Mbp in size with 32.4 mol% G+C content. Maximum-likelihood phylogeny of core proteins places it in the transitional group of basal to both and . It is distinct from existing named species, with maximum average nucleotide identity of 95.1% to and maximum digital DNA-DNA hybridization score similarity to at 80.1%. The closest similarity at the 16S rRNA gene (97.9%) and 4 (97.5%/97.6% respectively) is to 'Rickettsia senegalensis' and sp. cf9, both isolated from cat fleas (). We characterized growth at various temperatures and in multiple cell lines. The Tillamook isolate grows aerobically in Vero E6, RF/6A and DH82 cells, and growth is rapid at 28 °C and 32 °C. Using accepted genomic criteria, we propose the name sp. nov., with the type strain Tillamook 23. Strain Tillamook 23 is available from the Centers for Disease Control and Prevention Rickettsial Isolate Reference Collection (WDCM 1093), Atlanta, GA, USA (CRIRC accession number RTI001) and the Collection de Souches de l'Unité des Rickettsies (WDCM 875), Marseille, France (CSUR accession number R5043). Using accepted genomic criteria, we propose the name sp. nov., with the type strain Tillamook 23 (=CRIRC RTI001=R5043).
一种以前未被识别的物种于 1976 年从美国俄勒冈州蒂拉穆克县 1967 年采集的蜱虫池中分离出来。该分离株在雄性豚鼠腹腔内注射后引起低热和轻度阴囊水肿（）。随后的血清分型将该分离株与已知的斑疹伤寒和斑点热群物种区分开来；尽管如此，该分离株在随后的 30 年内仍未通过分子技术进行评估，也未鉴定到种水平。是美国西部最常被鉴定为叮咬人类的蜱虫，因此，对这种潜在致病的物种进行正式鉴定和特征描述是合理的。对蒂拉穆克分离株的全基因组测序显示其基因组大小为 1.43 Mbp，G+C 含量为 32.4 mol%。核心蛋白的最大似然系统发育将其置于与 和 均处于过渡组的基础上。它与现有的命名物种不同，与 的最大平均核苷酸同一性为 95.1%，与 的最大数字 DNA-DNA 杂交相似度为 80.1%，在 16S rRNA 基因（97.9%）和 4 （分别为 97.5%/97.6%）上与 'Rickettsia senegalensis' 和 sp. cf9 最为相似，后者均从猫蚤中分离出来（）。我们在不同温度和多种细胞系中对其生长特性进行了描述。蒂拉穆克分离株在 Vero E6、RF/6A 和 DH82 细胞中需氧生长，在 28°C 和 32°C 时生长迅速。根据公认的基因组标准，我们提议使用新名称 sp. nov.，其模式株为蒂拉穆克 23 株（Tillamook 23）。该菌株可从美国疾病控制与预防中心立克次体分离株参考收藏集（WDCM 1093），亚特兰大，GA，美国（CRIRC 登记号 RTI001）和集落收藏的单位的立克次体（WDCM 875），马赛，法国（CSUR 登记号 R5043）获得。根据公认的基因组标准，我们提议使用新名称 sp. nov.，其模式株为蒂拉穆克 23 株（=CRIRC RTI001=R5043）。
