Some lessons from<i>Rickettsia</i>genomics

Renesto, Patricia; Ogata, Hiroyuki; Audic, Stéphane; Claverie, Jean‐Michel; Raoult, Didier

doi:10.1016/j.femsre.2004.09.002

Cited by 73 publications

(99 citation statements)

References 118 publications

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“…pREIS1 and pREIS3 also encode ProQ, a regulator of ProP proline/betaine transporters, which are involved in osmoregularity and likely are critical for adaptation to intracellular environments (118,128). While proP genes are widespread and proliferated in all Rickettsia genomes (51,88,95), this is the first occurrence of proQ regulators. Two adjacent ORFs encoding small heat shock proteins, which are found on most rickettsial plasmids (8), are present on all plasmids, except pREIS3, and are duplicated on pREIS4.…”

Section: Resultsmentioning

confidence: 99%

A Rickettsia Genome Overrun by Mobile Genetic Elements Provides Insight into the Acquisition of Genes Characteristic of an Obligate Intracellular Lifestyle

et al. 2012

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We present the draft genome for the Rickettsia endosymbiont of Ixodes scapularis (REIS), a symbiont of the deer tick vector of Lyme disease in North America. Among Rickettsia species (Alphaproteobacteria: Rickettsiales), REIS has the largest genome sequenced to date (>2 Mb) and contains 2,309 genes across the chromosome and four plasmids (pREIS1 to pREIS4). The most remarkable finding within the REIS genome is the extraordinary proliferation of mobile genetic elements (MGEs), which contributes to a limited synteny with other Rickettsia genomes. In particular, an integrative conjugative element named RAGE (for Rickettsiales amplified genetic element), previously identified in scrub typhus rickettsiae (Orientia tsutsugamushi) genomes, is present on both the REIS chromosome and plasmids. Unlike the pseudogene-laden RAGEs of O. tsutsugamushi, REIS encodes nine conserved RAGEs that include F-like type IV secretion systems similar to that of the tra genes encoded in the Rickettsia bellii and R. massiliae genomes. An unparalleled abundance of encoded transposases (>650) relative to genome size, together with the RAGEs and other MGEs, comprise ϳ35% of the total genome, making REIS one of the most plastic and repetitive bacterial genomes sequenced to date. We present evidence that conserved rickettsial genes associated with an intracellular lifestyle were acquired via MGEs, especially the RAGE, through a continuum of genomic invasions. Robust phylogeny estimation suggests REIS is ancestral to the virulent spotted fever group of rickettsiae. As REIS is not known to invade vertebrate cells and has no known pathogenic effects on I. scapularis, its genome sequence provides insight on the origin of mechanisms of rickettsial pathogenicity.

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Section: Resultsmentioning

confidence: 99%

A Rickettsia Genome Overrun by Mobile Genetic Elements Provides Insight into the Acquisition of Genes Characteristic of an Obligate Intracellular Lifestyle

et al. 2012

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“…In B. burgdorferi (9,13,41) and R. conorii (43), both of which are tick-borne, spoT mRNAs were differentially expressed following vertebrate-to-arthropod host shifts and changes in nutritional stress. As obligate endosymbionts, rickettsiae do not synthesize many low-molecularweight metabolites, such as proline (40,52), and rely on membrane transporters for access to host cell metabolites. Proline/ betaine transporters are members of the ABC transporter family and have been classically defined as maintaining cellular osmotic integrity by transporting uncharged solutes across the plasma membrane (21).…”

Section: Discussionmentioning

confidence: 99%

Transposon Insertion Reveals pRM, a Plasmid ofRickettsia monacensis

Baldridge

Burkhardt

Felsheim

et al. 2007

Appl Environ Microbiol

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Until the recent discovery of pRF in Rickettsia felis, the obligate intracellular bacteria of the genus Rickettsia (Rickettsiales: Rickettsiaceae) were thought not to possess plasmids. We describe pRM, a plasmid from Rickettsia monacensis, which was detected by pulsed-field gel electrophoresis and Southern blot analyses of DNA from two independent R. monacensis populations transformed by transposon-mediated insertion of coupled green fluorescent protein and chloramphenicol acetyltransferase marker genes into pRM. Two-dimensional electrophoresis showed that pRM was present in rickettsial cells as circular and linear isomers. The 23,486-nucleotide (31.8% G/C) pRM plasmid was cloned from the transformant populations by chloramphenicol marker rescue of restriction enzyme-digested transformant DNA fragments and PCR using primers derived from sequences of overlapping restriction fragments. The plasmid was sequenced. Based on BLAST searches of the GenBank database, pRM contained 23 predicted genes or pseudogenes and was remarkably similar to the larger pRF plasmid. Two of the 23 genes were unique to pRM and pRF among sequenced rickettsial genomes, and 4 of the genes shared by pRM and pRF were otherwise found only on chromosomes of R. felis or the ancestral group rickettsiae R. bellii and R. canadensis. We obtained pulsed-field gel electrophoresis and Southern blot evidence for a plasmid in R. amblyommii isolate WB-8-2 that contained genes conserved between pRM and pRF. The pRM plasmid may provide a basis for the development of a rickettsial transformation vector.

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“…Fever, nausea, muscle pain, and headaches are among the symptoms of epidemic typhus disease. The occurrence of pink rash on the extremities followed on the stomach and buttocks after few days of infection are also observed (Renesto et al, 2005).…”

Section: Introductionmentioning

confidence: 89%

Seroprevalence of typhus fever at the Kality Prison, Addis Ababa, Ethiopia

Mariam¹,

Gelaw²,

Assefa³

2015

Biomed Res Ther

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Abstract-Background: Peoples living in crowded situations like refugee camps and prisons are highly vulnerable to louse-born typhus infection. The information on the prevalence of louse-borne typhus among prisoners in Ethiopia is limited. Hence, the aim of this study was to determine the prevalence of typhus among prisoners at the Kality Prison, Addis Ababa, Ethiopia. Methods: A five-year retrospective study was conducted from February to March 2014. A total of 6104 typhus fever suspected prisoners tested for typhus at the Kality Prison Hospital from 2008 to 2012 were included. Data on the seroprevalence of typhus were abstracted from Kality Prison Laboratory. Data were entered and analyzed using SPSS 20 statistical software. Descriptive statistics and Chi-square were computed. In all cases p-values less than 0.05 was taken as statistically significant. Results: The overall prevalence of typhus fever infection was 26.3%. The prevalence of typhus fever infection was found to be higher among prisoners within the age group of 41-50 years (36.9%) and also among male patients (27.3%). The prevalence of typhus fever infection was higher by the year 2009 (40.7%) and overall in the five-year period the summer (31.8%) and fall (30%) seasons showed higher seroprevalence of typhus. Conclusions: The prevalence of typhus fever infection at Kality prison was high. This high prevalence could be a possible risk for epidemic typhus fever infection within the prison and for the nearby population. Therefore, targeted public health intervention could be important in this high-risk population.

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Some lessons fromRickettsiagenomics

Cited by 73 publications

References 118 publications

A Rickettsia Genome Overrun by Mobile Genetic Elements Provides Insight into the Acquisition of Genes Characteristic of an Obligate Intracellular Lifestyle

A Rickettsia Genome Overrun by Mobile Genetic Elements Provides Insight into the Acquisition of Genes Characteristic of an Obligate Intracellular Lifestyle

Transposon Insertion Reveals pRM, a Plasmid ofRickettsia monacensis

Seroprevalence of typhus fever at the Kality Prison, Addis Ababa, Ethiopia

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