A comparative view of Rickettsia tsutsugamushi and the other groups of rickettsiae

Tamura, Akira; Urakami, Hiroshi; Ohashi, Norio

doi:10.1007/bf00145675

Cited by 24 publications

(16 citation statements)

References 90 publications

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“…These inherent drawbacks are due to several biological characteristics of orientia that are not seen in other rickettsial organisms. First, as has been shown previously (22) and in this study, O. tsutsugamushi is very fragile. Therefore, bacteria preparation may include many inactive or dead orientia after a short period of partial purification.…”

Section: Discussionsupporting

confidence: 76%

Characterization of Monoclonal Antibody Reacting Exclusively against Intracellular Orientia tsutsugamushi

Mee-Kyung

Odgerel

Chung

et al. 2002

Microbiology and Immunology

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Intracellular bacteria often change the expression of their genes in order to adapt to new environmental conditions. Here we describe a monoclonal antibody (MAb) that reacts exclusively against intracellular Orientia tsutsugamushi Although MAb applied to the 56‐kDa protein, a major outer membrane protein, reacted against a large number of bacteria that had attached to host cells at the early stage of infection, M686–13 reacted against only a minor portion of the attached bacteria. In the later stage of the intracellular growth cycle, both antibodies showed identical staining patterns by double immunofluorescent staining. These results suggest that M686–13 reacted to an epitope or a protein that had probably been expressed during the intracellular growth cycle and rapidly diluted or degraded upon release into the extracellular environment. Although its molecular characteristics remain unknown, the reactive antigen may prove to be a novel developmental antigen and this MAb could be used as reagent for the staining of viable O. tsutsugamushi.

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Section: Discussionsupporting

confidence: 76%

Characterization of Monoclonal Antibody Reacting Exclusively against Intracellular Orientia tsutsugamushi

Mee-Kyung

Odgerel

Chung

et al. 2002

Microbiology and Immunology

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“…and W.M.C., unpublished data) [132,138]. O. tsutsugamushi contains no lipopolysaccharide or outer membrane glycoproteins typical of most gram-negative organisms, and this method yields at least 30 major proteins, including 110-kDa, 70-kDa, 60-kDa, 56-kDa, 47-kDa, and ∼22-25-kDa proteins [139][140][141][142]. The dramatic antigenic variability of scrub typhus rickettsiae appears to reside primarily but not exclusively in the 110-kDa and 56-kDa proteins [143].…”

Section: Cfmentioning

confidence: 99%

Scrub Typhus: The Geographic Distribution of Phenotypic and Genotypic Variants ofOrientia tsutsugamushi

et al. 2009

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Orientia tsutsugamushi is the etiological agent of scrub typhus, an acute, mite-borne, febrile illness that occurs in the Asia-Pacific region. Historically, strain characterization used serological analysis and revealed dramatic antigenic diversity. Eyeing a recommendation of potential vaccine candidates for broad protection, we review geographic diversity and serological and DNA prevalences. DNA analysis together with immunological analysis suggest that the prototype Karp strain and closely related strains are the most common throughout the region of endemicity. According to serological analysis, approximately 50% of isolates are seroreactive to Karp antisera, and approximately one-quarter of isolates are seroreactive to antisera against the prototype Gilliam strain. Molecular methods reveal greater diversity. By molecular methods, strains phylogenetically similar to Karp make up approximately 40% of all genotyped isolates, followed by the JG genotype group (Japan strains serotypically similar to the Gilliam strain but genetically non-Gilliam; 18% of all genotyped isolates). Three other genotype groups (Kato-related, Kawasaki-like, and TA763-like) each represent approximately 10% of genotyped isolates. Strains genetically similar to the Gilliam strain make up only 5% of isolates. Strains from these groups should be included in any potential vaccine.

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“…This species has not been studied as intensively as the other groups, and its relationship to other members of the genus is problematic. In fact, R. tsutsugamushi is so distinct that some workers have suggested that it should be reclassified in another bacterial genus (32). While the three Rickettsia biotypes are very distinct from each other, a few organisms classified in the genus Rickettsia do not fall distinctly into any of the biotypes.…”

mentioning

confidence: 99%

Ancestral Divergence of Rickettsia bellii from the Spotted Fever and Typhus Groups of Rickettsia and Antiquity of the Genus Rickettsia

Stothard

Clark

Fuerst

1994

International Journal of Systematic Bacteriology

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The eubacterial genus Rickettsia belongs to the cu subgroup of the phylum Proteobacteriu. This genus is usually divided into three biotypes on the basis of vector host and antigenic cross-reactivity characteristics. However, the species Rickettsia bellii does not fit into this classification scheme; this organism has characteristics common to both the spotted fever group and the typhus group biotypes and also exhibits some unique features. Sequences of the 16s rRNA and 23s rRNA genes from Rickettsia rickettsii (spotted fever group), Rickettsia prowazekii (typhus group), and R. bellii were studied to determine the position of R. bellii in the rickettsia1 classification scheme. The 23s rRNA gene sequences described in this paper are the first 23s rRNA sequences reported for any member of the Rickettsiuceue. The 23s rRNA gene contains substantially more phylogenetic information than is contained in the 16s rRNA sequences, and the 23s rRNA gene sequence has diverged about 1.9 times faster in the three Rickettsia species which we studied. Taken together, the molecular data obtained from the two genes indicate that R. bellii is not a member of either the spotted fever group or the typhus group; rather, this organism appears to be the product of a divergence which predates the separation of the genus into the spotted fever group and the typhus group. Consequently, different combinations of the ancestral characteristics retained by R. bellii have been retained in the more derived lineages of the genus. A comparison of the 16s rRNA and 23s rRNA gene sequences of Rickettsia strains with other proteobacterial sequences confirmed that the genus Rickettsia is a unique deeply branching member of the cu subgroup of the Proteobacteria and that the Rickettsia species form a monophyletic cluster. While divergence of the contemporary members of the genus Rickettsia occurred recently, the unique evolutionary line represented by this genus appears to be very old.Rickettsia strains are small, gram-negative bacteria that are intimately associated with eukaryotic cells and are members of a diverse family, the Rickettsiaceae, which also includes other intracellular organisms, including the genera Ehrlichia, Wolbachia, Anaplasma, and Cowdria (4,36). Rickettsiae have natural arthropod hosts (either ticks, mites, or insects) and can be pathogenic for humans and other vertebrates. The obligately intracellular lifestyle and fastidious nature of these organisms have made them difficult to study. A number of genotypic and phenotypic characteristics indicate that the Rickettsia species are closely related, and this genus is now recognized as the sole member of a branch of the cx subgroup Proteobacteriu (8) on the basis of 16s rRNA cataloging and partial 16s rRNA gene sequence data (34).The genus Rickettsia is divided into three biotypes on the basis of immunological cross-reactivity and ecological characteristics (36). Rickettsia species are placed into the spotted fever group (SFG), the typhus group (TG), or the scrub typhus group on the basis...

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A comparative view of Rickettsia tsutsugamushi and the other groups of rickettsiae

Cited by 24 publications

References 90 publications

Characterization of Monoclonal Antibody Reacting Exclusively against Intracellular Orientia tsutsugamushi

Characterization of Monoclonal Antibody Reacting Exclusively against Intracellular Orientia tsutsugamushi

Scrub Typhus: The Geographic Distribution of Phenotypic and Genotypic Variants ofOrientia tsutsugamushi

Ancestral Divergence of Rickettsia bellii from the Spotted Fever and Typhus Groups of Rickettsia and Antiquity of the Genus Rickettsia

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