Discovery of Novel Rickettsiella spp. in Ixodid Ticks from Western Canada

Abstract

The genomic DNA from four species of ixodid ticks in western Canada was tested for the presence of Rickettsiella by PCR analyses targeting the 16S rRNA gene. Eighty-eight percent of the Ixodes angustus (n ‫؍‬ 270), 43% of the I. sculptus (n ‫؍‬ 61), and 4% of the I. kingi (n ‫؍‬ 93) individuals examined were PCR positive for Rickettsiella, whereas there was no evidence for the presence of Rickettsiella in Dermacentor andersoni (n ‫؍‬ 45). Three different single-strand conformation polymorphism profiles of the 16S rRNA gene were detected among amplicons derived from Rickettsiella-positive ticks, each corresponding to a different sequence type. Furthermore, each sequence type was associated with a different tick species. Phylogenetic analyses of sequence data of the 16S rRNA gene and three other genes (rpsA, gidA, and sucB) revealed that all three sequence types were placed in a clade that contained species and pathotypes of the genus Rickettsiella. The bacterium in I. kingi represented the sister taxon to the Rickettsiella in I. sculptus, and both formed a clade with Rickettsiella grylli from crickets (Gryllus bimaculatus) and "R. ixodidis" from I. woodi. In contrast, the Rickettsiella in I. angustus was not a member of this clade but was placed external to the clade comprising the pathotypes of R. popilliae. The results indicate the existence of at least two new species of Rickettsiella: one in I. angustus and another in I. kingi and I. sculptus. However, the Rickettsiella strains in I. kingi and I. sculptus may also represent different species because each had unique sequences for all four genes.

Infection With a Novel Rickettsiella Species in Emperor Scorpions (Pandinus imperator)

“…Previous investigations, however, have demonstrated that phylogenetic relationships between Rickettsiella are better resolved using protein-coding gene sequences, with rps A, gid A, and suc B identified as particularly informative. 2,32,34 Results of this analysis clearly illustrate the discrimination of the emperor scorpion Rickettsiella detailed in this article from other hosts, and also provide evidence of the utility of multi-locus sequence typing primers for the detection and characterization of these organisms. 32 One limitation of our study was that protein-coding gene sequence data were not obtained from case 2, perhaps due to poor-quality DNA template derived from the fixed and embedded tissue, and though partial sequence of the 16S rRNA gene was positive for Rickettsiella , this case cannot be conclusively connected to the other cases based on sequence data.…”

“…are well recognized as common pathogens and occasionally symbionts of a wide variety of arthropods. 2,12,31,45,55 Rickettsiella were previously considered to be a subspecies of the genus Rickettsia , but recent reclassification based on 16S ribosomal RNA (rRNA) gene sequences 45 has placed Rickettsiella in a separate genus in the family Coxiellaceae , order Legionellales , class Gammaproteobacteria . 22 There are currently 4 recognized species of Rickettsiella : R. grylli , R. chironami , R. popilliae , and R. stethorae with several pathotypes identified based on clinical presentation, although no type-strain isolates of these pathotypes have been successfully cultured.…”

Diversity of bacteriome associated with Phlebotomus chinensis (Diptera: Psychodidae) sand flies in two wild populations from China

“…Spiroplasma as endosymbionts has been identified in Drosophila 39404142, ticks4344 and mosquitoes45. Diplorickettsia , Coxiella and Rickettsiella are obligate endosymbionts that have been identified in ticks28464748 and leafhoppers49. Here, we reported for the first time the presence of Spiroplasma and taxa related to Diplorickettsia and Rickettsiella in Ph.…”

Differences in Gut Microbiome Composition Between Sympatric Wild and Allopatric Laboratory Populations of Omnivorous Cockroaches

“…Rickettsiella are most commonly known as intracellular insect pathogens ( Leclerque and Kleespies, 2012 ), however, there is one symbiotic species found in aphids that can be found in extracellular tissues or in the hemolymph ( Tsuchida et al, 2010 ). Rickettsiella can be transmitted both vertically and horizontally between insects ( Iasur-Kruh et al, 2013 ; Marshall et al, 2017 ), and certain Rickettsiella species have been found to be transferred from insects to mammals via insect bites ( Anstead and Chilton, 2014 ). Similarly, Arcobacter is an emerging animal and human pathogen with multiple roles of transmission ( Collado and Figueras, 2011 ; Barboza et al, 2017 ).…”