GenotypingRickettsia prowazekiiIsolates

Zhu, Yong; Medina-Sanchez, Aaron; Bouyer, Donald H.; Walker, David H.; Yu, Xue Jie

doi:10.3201/eid1408.080444

Cited by 9 publications

(5 citation statements)

References 13 publications

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“…1, lanes 6 and 10). In order to explore any change in the RFLP pattern depending on different strains, we compared the RFLP patterns of three R. prowazekii strains (Madrid E, Breinl, and GvV-250) with different genotyping previously reported [10], and found that the RFLP was identical for the three strains, confirming the utility of our analysis to identify the species (fig. 2).…”

Section: Resultssupporting

confidence: 81%

“…Functionally, the ompB gene has been well conserved in rickettsial evolution, and has been used as a taxonomic, phylogenetic, and diagnostic tool [10, 13–14]. The identity of the ompB sequence among species belonging to the same group is high, and on average the SFG Rickettsia have 96%, the TG 92%, and the TRG 91% identity.…”

Section: Discussionmentioning

confidence: 99%

“…2) [10], and to differentiate clinically related rickettsioses such as murine typhus and fleaborne spotted fever (fig. 1) [15, 16].…”

Section: Discussionmentioning

confidence: 99%

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Simple Method to Differentiate among Rickettsia Species

et al. 2013

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In this work we present a new option to identify 11 rickettsial species that cause human rickettsioses, with some advantages over the previous methods described. Using rickettsial isolates from 11 Rickettsia species as a sample, we used the polymerase chain reaction to amplify a 990- to 1,000-bp DNA fragment from the ompB gene, common for the 11 Rickettsia species analyzed in this study, which were digested with AluI restriction enzyme to obtain different digestion patterns. This restriction pattern can be visualized using a polyacrylamide gel electrophoresis technique. Using this method we could differentiate between the 11 Rickettsia species analyzed regardless of the group to which the Rickettsia belonged. We developed a simple method to identify 11 Rickettsia species which cause human rickettsioses using polymerase chain reaction and restriction fragment length polymorphism techniques with the advantage that it only needs one amplicon and only one restriction enzyme to obtain the restriction pattern. The identification of the species infecting vectors, reservoirs, and humans is essential to establish the ecological and behavioral ecosystem involved in its maintenance and transmission in nature in the specific region where the pathogen is circulating. This method is very helpful to identify Rickettsia species in a short time.

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Section: Resultssupporting

confidence: 81%

Section: Discussionmentioning

confidence: 99%

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Simple Method to Differentiate among Rickettsia Species

et al. 2013

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“…However, the 16S–23S rDNA spacer is not usable in Rickettsia species as these genes are not contiguous (Andersson et al , 1995, 1999; Ogata et al , 2001). Genotyping studies based on the presence or absence of single‐nucleotide polymorphisms (SNP) (Karpathy, Dasch & Eremeeva, 2007; Zhu et al , 2008) and variable nucleotide tandem repeats (VNTR) (Eremeeva et al , 2006) in intergenic spacers have been applied to Rickettsia spp. Moreover, multi‐spacer typing (MST) has been developed selecting the most variable noncoding regions between R. prowazekii and R. conorii .…”

Section: Phylogeny and Taxonomymentioning

confidence: 99%

Rickettsial evolution in the light of comparative genomics

2010

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Rickettsia are best known as strictly intracellular vector-borne bacteria that cause mild to severe diseases in humans and other animals. Recent advances in molecular tools and biological experiments have unveiled a wide diversity of Rickettsia spp. that include species with a broad host range and some species that act as endosymbiotic associates. Molecular phylogenies of Rickettsia spp. contain some ambiguities, such as the position of R. canadensis and relationships within the spotted fever group. In the modern era of genomics, with an ever-increasing number of sequenced genomes, there is enhanced interest in the use of whole-genome sequences to understand pathogenesis and assess evolutionary relationships among rickettsial species. Rickettsia have small genomes (1.1-1.5 Mb) as a result of reductive evolution. These genomes contain split genes, gene remnants and pseudogenes that, owing to the colinearity of some rickettsial genomes, may represent different steps of the genome degradation process. Genomics reveal extreme genome reduction and massive gene loss in highly vertebrate-pathogenic Rickettsia compared to less virulent or endosymbiotic species. Information gleaned from rickettsial genomics challenges traditional concepts of pathogenesis that focused primarily on the acquisition of virulence factors. Another intriguing phenomenon about the reduced rickettsial genomes concerns the large fraction of non-coding DNA and possible functionality of these "non-coding" sequences, because of the high conservation of these regions. Despite genome streamlining, Rickettsia spp. contain gene families, selfish DNA, repeat palindromic elements and genes encoding eukaryotic-like motifs. These features participate in sequence and functional diversity and may play a crucial role in adaptation to the host cell and pathogenesis. Genome analyses have identified a large fraction of mobile genetic elements, including plasmids, suggesting the possibility of lateral gene transfer in these intracellular bacteria. Phylogenetic analyses have identified several candidates for horizontal gene acquisition among Rickettsia spp. including tra, pat2, and genes encoding for the type IV secretion system and ATP/ADP translocase that may have been acquired from bacteria living in amoebae. Gene loss, gene duplication, DNA repeats and lateral gene transfer all have shaped rickettsial genome evolution. A comprehensive analysis of the entire genome, including genes and non-coding DNA, will help to unlock the mysteries of rickettsial evolution and pathogenesis.

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“…Due to different sources and different passages, R. prowazekii strain can be grouped in to three virulence groups: high virulence group represented by Breinl strain, medium virulence group represented by flying squirrel isolates and low virulence or non-virulence group represented by Madrid E strain and its revertant strains. All strains of R. prowazekii can be differentiated by sequencing several loci of the genome of R. prowazekii (Zhu et al, 2008). R. rickettsii strains were not genetically typed except for virulent R strain and nonvirulent Iowa strains, whose whole genomes were completely sequenced (Ellison et al, 2008).…”

Section: Experimental Vaccines and Other Potential Vaccine Prospectsmentioning

confidence: 99%