rickettsia rickettsii

Summary

Summary: A species of gram-negative, aerobic bacteria that is the etiologic agent of ROCKY MOUNTAIN SPOTTED FEVER. Its cells are slightly smaller and more uniform in size than those of RICKETTSIA PROWAZEKII.

Top Publications

  1. de Lemos E, Alvarenga F, Cintra M, Ramos M, Paddock C, Ferebee T, et al. Spotted fever in Brazil: a seroepidemiological study and description of clinical cases in an endemic area in the state of São Paulo. Am J Trop Med Hyg. 2001;65:329-34 pubmed
    ..twenty-five blood samples were tested by an indirect immunofluorescence assay for antibodies reactive with Rickettsia rickettsii. Twenty-two (4.2%) of these samples demonstrated titers > or = 1:64...
  2. Horta M, Labruna M, Sangioni L, Vianna M, Gennari S, Galvao M, et al. Prevalence of antibodies to spotted fever group rickettsiae in humans and domestic animals in a Brazilian spotted fever-endemic area in the state of São Paulo, Brazil: serologic evidence for infection by Rickettsia rickettsii and another spotted feve. Am J Trop Med Hyg. 2004;71:93-7 pubmed
    ..area for Brazilian spotted fever, an indirect immunofluorescence assay (IFA) detected antibodies against Rickettsia rickettsii in 17 (77.3%) horses, 5 (31.3%) dogs (titers ranging from 64 to 4,048), and none of 4 donkeys or 50 humans...
  3. Gilmore R, Joste N, McDonald G. Cloning, expression and sequence analysis of the gene encoding the 120 kD surface-exposed protein of Rickettsia rickettsii. Mol Microbiol. 1989;3:1579-86 pubmed
    b>Rickettsia rickettsii (R strain) genomic DNA was partially digested and cloned into the lambda expression vector gt11 generating a genomic clone bank...
  4. Ellison D, Clark T, Sturdevant D, Virtaneva K, Porcella S, Hackstadt T. Genomic comparison of virulent Rickettsia rickettsii Sheila Smith and avirulent Rickettsia rickettsii Iowa. Infect Immun. 2008;76:542-50 pubmed
    b>Rickettsia rickettsii is an obligate intracellular pathogen that is the causative agent of Rocky Mountain spotted fever. To identify genes involved in the virulence of R. rickettsii, the genome of an avirulent strain, R...
  5. Dumler J, Walker D. Rocky Mountain spotted fever--changing ecology and persisting virulence. N Engl J Med. 2005;353:551-3 pubmed
  6. Paddock C, Brenner O, Vaid C, Boyd D, Berg J, Joseph R, et al. Short report: concurrent Rocky Mountain spotted fever in a dog and its owner. Am J Trop Med Hyg. 2002;66:197-9 pubmed
    ..Previous reports of concurrent RMSF in dogs and their owners are reviewed, and the epidemiologic significance of this occurrence is discussed...
  7. Eremeeva M, Zambrano M, Anaya L, Beati L, Karpathy S, Santos Silva M, et al. Rickettsia rickettsii in Rhipicephalus ticks, Mexicali, Mexico. J Med Entomol. 2011;48:418-21 pubmed
    Circulation of a unique genetic type of Rickettsia rickettsii in ticks of the Rhipicephalus sanguineus complex was detected in Mexicali, Baja California, Mexico. The Mexican R...
  8. da Silva Costa L, Nunes P, Soares J, Labruna M, Camargo Mathias M. Distribution of Rickettsia rickettsii in ovary cells of Rhipicephalus sanguineus (Latreille1806) (Acari: Ixodidae). Parasit Vectors. 2011;4:222 pubmed publisher
    ..Spotted Fever (BSF) for humans, the present study aimed to describe the distribution of the bacterium Rickettsia rickettsii, the etiological agent of BSF, in different regions of the ovaries of R...
  9. Mikszewski J, Vite C. Central nervous system dysfunction associated with Rocky Mountain spotted fever infection in five dogs. J Am Anim Hosp Assoc. 2005;41:259-66 pubmed
    ..indirect fluorescent antibody titer or a positive semiquantitative enzyme screening immunoassay titer for Rickettsia rickettsii at the time of presentation...

More Information

Publications66

  1. Rahman M, Simser J, Macaluso K, Azad A. Functional analysis of secA homologues from rickettsiae. Microbiology. 2005;151:589-96 pubmed
    ..of the putative secA gene, an essential component of the Sec-dependent protein secretion pathway, from Rickettsia rickettsii and Rickettsia typhi, the aetiological agents of Rocky Mountain spotted fever and murine typhus, ..
  2. Labruna M, Ogrzewalska M, Soares J, Martins T, Soares H, Moraes Filho J, et al. Experimental infection of Amblyomma aureolatum ticks with Rickettsia rickettsii. Emerg Infect Dis. 2011;17:829-34 pubmed publisher
    We experimentally infected Amblyomma aureolatum ticks with the bacterium Rickettsia rickettsii, the etiologic agent of Rocky Mountain spotted fever (RMSF). These ticks are a vector for RMSF in Brazil. R...
  3. Pacheco R, Moraes Filho J, Guedes E, Silveira I, Richtzenhain L, Leite R, et al. Rickettsial infections of dogs, horses and ticks in Juiz de Fora, southeastern Brazil, and isolation of Rickettsia rickettsii from Rhipicephalus sanguineus ticks. Med Vet Entomol. 2011;25:148-55 pubmed publisher
    ..de Fora, state of Minas Gerais, Brazil, during the years 2007 and 2008, when fatal cases of BSF (caused by Rickettsia rickettsii) were reported...
  4. Eremeeva M, Klemt R, Santucci Domotor L, Silverman D, Dasch G. Genetic analysis of isolates of Rickettsia rickettsii that differ in virulence. Ann N Y Acad Sci. 2003;990:717-22 pubmed
    ..rickettsii, DNA sequence analysis was performed on a portion of a 2,672 bp region spanning the 3'-end of polA to the 5'-end of dnaE. Except for Hlp#2 strain these isolates were highly conserved in the regions sequenced...
  5. Pinter A, Labruna M. Isolation of Rickettsia rickettsii and Rickettsia bellii in cell culture from the tick Amblyomma aureolatum in Brazil. Ann N Y Acad Sci. 2006;1078:523-9 pubmed
    Brazilian spotted fever (BSF) is a highly lethal disease caused by Rickettsia rickettsii. In the present study, rickettsial infection was evaluated in 669 Amblyomma aureolatum adult ticks collected from naturally infested dogs in Taiaç..
  6. Demma L, Traeger M, Nicholson W, Paddock C, Blau D, Eremeeva M, et al. Rocky Mountain spotted fever from an unexpected tick vector in Arizona. N Engl J Med. 2005;353:587-94 pubmed
    Rocky Mountain spotted fever is a life-threatening, tick-borne disease caused by Rickettsia rickettsii. This disease is rarely reported in Arizona, and the principal vectors, Dermacentor species ticks, are uncommon in the state...
  7. Baldridge G, Burkhardt N, Simser J, Kurtti T, Munderloh U. Sequence and expression analysis of the ompA gene of Rickettsia peacockii, an endosymbiont of the Rocky Mountain wood tick, Dermacentor andersoni. Appl Environ Microbiol. 2004;70:6628-36 pubmed publisher
    ..by Rickettsia peacockii, a tick symbiotic rickettsia that interferes with transmission of virulent Rickettsia rickettsii. To elucidate the molecular relationships between the two rickettsiae and glean information on how to ..
  8. Galvao M, Lamounier J, Bonomo E, Tropia M, Rezende E, Calic S, et al. [Emerging and reemerging rickettsiosis in an endemic area of Minas Gerais State, Brazil]. Cad Saude Publica. 2002;18:1593-7 pubmed
    ..81%), respectively. The results in schoolchildren and the presence of canine seroreactivity to Ehrlichiaspecies that are potentially pathogenic to humans suggests the risk of transmission of other Rickettsiaein the study area...
  9. Marshall G, Stout G, Jacobs R, Schutze G, Paxton H, Buckingham S, et al. Antibodies reactive to Rickettsia rickettsii among children living in the southeast and south central regions of the United States. Arch Pediatr Adolesc Med. 2003;157:443-8 pubmed
    ..2 per million, but studies have suggested that human infection with Rickettsia rickettsii may be more common...
  10. Heinzen R, Grieshaber S, Van Kirk L, Devin C. Dynamics of actin-based movement by Rickettsia rickettsii in vero cells. Infect Immun. 1999;67:4201-7 pubmed
    ..In this study, we directly compared the dynamics and behavior of ABM of Rickettsia rickettsii and Listeria monocytogenes...
  11. Soares J, Soares H, Barbieri A, Labruna M. Experimental infection of the tick Amblyomma cajennense, Cayenne tick, with Rickettsia rickettsii, the agent of Rocky Mountain spotted fever. Med Vet Entomol. 2012;26:139-51 pubmed publisher
    ..laboratory, Amblyomma cajennense (Acari: Ixodidae) (Fabricius) larvae, nymphs and adults were exposed to Rickettsia rickettsii by feeding on needle-inoculated animals, and thereafter reared on uninfected guinea pigs or rabbits...
  12. Dantas Torres F. Rocky Mountain spotted fever. Lancet Infect Dis. 2007;7:724-32 pubmed
    Rocky Mountain spotted fever (RMSF) is a life-threatening disease caused by Rickettsia rickettsii, an obligately intracellular bacterium that is spread to human beings by ticks...
  13. de Lemos E, Rozental T, Villela C. Brazilian spotted fever: description of a fatal clinical case in the State of Rio de Janeiro. Rev Soc Bras Med Trop. 2002;35:523-5 pubmed
    ..Serologic test in a serum sample, using an immunofluorescence assay, revealed reactive IgM/IgG...
  14. Oliveira K, Pinter A, Medina Sanchez A, Boppana V, Wikel S, Saito T, et al. Amblyomma imitator ticks as vectors of Rickettsia rickettsii, Mexico. Emerg Infect Dis. 2010;16:1282-4 pubmed publisher
    ..Sequence analyses of 17-kD common antigen and outer membrane protein A and B gene fragments showed to it to be R. rickettsii, which suggested a potential new vector for this bacterium...
  15. Felsheim R, Kurtti T, Munderloh U. Genome sequence of the endosymbiont Rickettsia peacockii and comparison with virulent Rickettsia rickettsii: identification of virulence factors. PLoS ONE. 2009;4:e8361 pubmed publisher
    ..Its presence in ticks is correlated with reduced prevalence of Rickettsia rickettsii, the agent of Rocky Mountain Spotted Fever...
  16. Labruna M, Ogrzewalska M, Martins T, Pinter A, Horta M. Comparative susceptibility of larval stages of Amblyomma aureolatum, Amblyomma cajennense, and Rhipicephalus sanguineus to infection by Rickettsia rickettsii. J Med Entomol. 2008;45:1156-9 pubmed
    ..aureolatum (Pallas), and Rhipicephalus sanguineus (Latreille) to infection by a Brazilian strain of Rickettsia rickettsii. Guinea pigs experimentally infected by R...
  17. Temenak J, Anderson B, McDonald G. Molecular cloning, sequence and characterization of cjsT, a putative protease from Rickettsia rickettsii. Microb Pathog. 2001;30:221-8 pubmed
    The cloning and sequencing of a gene from Rickettsia rickettsii which confers haemolytic activity on Escherichia coli strain TB1 is described...
  18. Breitschwerdt E, Papich M, Hegarty B, Gilger B, Hancock S, Davidson M. Efficacy of doxycycline, azithromycin, or trovafloxacin for treatment of experimental Rocky Mountain spotted fever in dogs. Antimicrob Agents Chemother. 1999;43:813-21 pubmed
    Dogs were experimentally inoculated with Rickettsia rickettsii (canine origin) in order to compare the efficacies of azithromycin and trovafloxacin to that of the current antibiotic standard, doxycycline, for the treatment of Rocky ..
  19. Ammerman N, Beier Sexton M, Azad A. Laboratory maintenance of Rickettsia rickettsii. Curr Protoc Microbiol. 2008;Chapter 3:Unit 3A.5 pubmed publisher
    This unit includes protocols for the laboratory maintenance of the obligate intracellular bacterium Rickettsia rickettsii, including propagation in mammalian cell cultures, as well as isolation, counting, and storage procedures...
  20. Breitschwerdt E, Davidson M, Hegarty B, Papich M, Grindem C. Prednisolone at anti-inflammatory or immunosuppressive dosages in conjunction with doxycycline does not potentiate the severity of Rickettsia rickettsii infection in dogs. Antimicrob Agents Chemother. 1997;41:141-7 pubmed
    Dogs were experimentally inoculated with Rickettsia rickettsii to determine if anti-inflammatory or immunosuppressive dosages of prednisolone, when administered in conjunction with an antirickettsial antibiotic (doxycycline), induced ..
  21. Clark T, Lackey A, Kleba B, Driskell L, Lutter E, Martens C, et al. Transformation frequency of a mariner-based transposon in Rickettsia rickettsii. J Bacteriol. 2011;193:4993-5 pubmed publisher
    Transformation frequencies of a mariner-based transposon system in Rickettsia rickettsii were determined using a plaque assay system for enumeration and isolation of mutants. Sequence analysis of insertion sites in both R...
  22. Wikswo M, Hu R, Metzger M, Eremeeva M. Detection of Rickettsia rickettsii and Bartonella henselae in Rhipicephalus sanguineus ticks from California. J Med Entomol. 2007;44:158-62 pubmed
    ..These findings extend the area where Rickettsia rickettsii may be vectored by Rh. sanguineus. Rh...
  23. Chen L, Sexton D. What's new in Rocky Mountain spotted fever?. Infect Dis Clin North Am. 2008;22:415-32, vii-viii pubmed publisher
    ..Decisions about giving empiric therapy to such patients are difficult and require skill and careful judgement...
  24. Horta M, Moraes Filho J, Casagrande R, Saito T, Rosa S, Ogrzewalska M, et al. Experimental infection of opossums Didelphis aurita by Rickettsia rickettsii and evaluation of the transmission of the infection to ticks Amblyomma cajennense. Vector Borne Zoonotic Dis. 2009;9:109-18 pubmed publisher
    The present study evaluated the infection of opossums (Didelphis aurita) by Rickettsia rickettsii and their role as amplifier hosts for horizontal transmission of R. rickettsii to Amblyomma cajennense ticks...
  25. Joshi S, Kovács A. Rickettsia rickettsii infection causes apoptotic death of cultured cerebellar granule neurons. J Med Microbiol. 2007;56:138-41 pubmed
  26. Clark T, Ellison D, Kleba B, Hackstadt T. Complementation of Rickettsia rickettsii RelA/SpoT restores a nonlytic plaque phenotype. Infect Immun. 2011;79:1631-7 pubmed publisher
    ..We have selected spontaneous mutant pairs from two independent strains of Rickettsia rickettsii, the virulent R strain and the avirulent Iowa strain. A nonlytic variant of R...
  27. Gilmore R, Joste N, McDonald G. Cloning, expression and sequence analysis of the gene encoding the 120 kDa surface-exposed protein of Rickettsia rickettsii. Mol Microbiol. 1991;5:3089 pubmed
  28. Rahman M, Simser J, Macaluso K, Azad A. Molecular and functional analysis of the lepB gene, encoding a type I signal peptidase from Rickettsia rickettsii and Rickettsia typhi. J Bacteriol. 2003;185:4578-84 pubmed
    The type I signal peptidase lepB genes from Rickettsia rickettsii and Rickettsia typhi, the etiologic agents of Rocky Mountain spotted fever and murine typhus, respectively, were cloned and characterized...
  29. Guedes E, Leite R, Prata M, Pacheco R, Walker D, Labruna M. Detection of Rickettsia rickettsii in the tick Amblyomma cajennense in a new Brazilian spotted fever-endemic area in the state of Minas Gerais. Mem Inst Oswaldo Cruz. 2005;100:841-5 pubmed
    ..yielded the expected bands that by sequencing, showed 100% identity to the corresponding sequences of the Rickettsia rickettsii gene fragments gltA (1063-bp), ompA (457-bp), and ompB (720-bp). The minimal infection rate of R...
  30. Bechelli J, Rydkina E, Colonne P, Sahni S. Rickettsia rickettsii infection protects human microvascular endothelial cells against staurosporine-induced apoptosis by a cIAP(2)-independent mechanism. J Infect Dis. 2009;199:1389-98 pubmed publisher
    ..Here, we investigate whether Rickettsia rickettsii-infected host endothelial cells resist the effects of staurosporine, a potent inducer of apoptosis, and we ..
  31. Ellison D, Clark T, Sturdevant D, Virtaneva K, Hackstadt T. Limited transcriptional responses of Rickettsia rickettsii exposed to environmental stimuli. PLoS ONE. 2009;4:e5612 pubmed publisher
    ..We examined the transcriptional responses of Rickettsia rickettsii, the agent of Rocky Mountain spotted fever, to a variety of environmental signals expected to be ..
  32. Freitas L, Faccini J, Labruna M. Experimental infection of the rabbit tick, Haemaphysalis leporispalustris, with the bacterium Rickettsia rickettsii, and comparative biology of infected and uninfected tick lineages. Exp Appl Acarol. 2009;47:321-45 pubmed publisher
    ..that evaluated experimental infections of Haemaphysalis leporispalustris ticks by a Brazilian strain of Rickettsia rickettsii, and their effect on tick biology. In experiment I, ticks were exposed to R...
  33. Moraes Filho J, Pinter A, Pacheco R, Gutmann T, Barbosa S, Gonzáles M, et al. New epidemiological data on Brazilian spotted fever in an endemic area of the state of São Paulo, Brazil. Vector Borne Zoonotic Dis. 2009;9:73-8 pubmed publisher
    ..sanguineus in the epidemiology of R. rickettsii, corroborating previous findings in Mexico and the United States, where R. sanguineus has been implicated in the transmission of R. rickettsii to humans...
  34. Rydkina E, Turpin L, Sahni S. Activation of p38 mitogen-activated protein kinase module facilitates in vitro host cell invasion by Rickettsia rickettsii. J Med Microbiol. 2008;57:1172-5 pubmed publisher
  35. Eremeeva M, Bosserman E, Zambrano M, Demma L, Dasch G. Molecular typing of novel Rickettsia rickettsii isolates from Arizona. Ann N Y Acad Sci. 2006;1078:573-7 pubmed
    Seven isolates of Rickettsia rickettsii were obtained from a skin biopsy, two whole-blood specimens, and from Rhipicephalus sanguineus ticks from eastern Arizona. Molecular typing of seven isolates of R...
  36. Gilmore R, Cieplak W, Policastro P, Hackstadt T. The 120 kilodalton outer membrane protein (rOmp B) of Rickettsia rickettsii is encoded by an unusually long open reading frame: evidence for protein processing from a large precursor. Mol Microbiol. 1991;5:2361-70 pubmed
    A Rickettsia rickettsii outer surface membrane protein (rOmp B), of an apparent molecular mass of 120 kilodaltons, is a major surface antigen of the Rickettsiae that displays genus, species, and sub-species specific antigenic ..
  37. Rydkina E, Turpin L, Sahni S. Rickettsia rickettsii infection of human macrovascular and microvascular endothelial cells reveals activation of both common and cell type-specific host response mechanisms. Infect Immun. 2010;78:2599-606 pubmed publisher
    ..heme oxygenase 1 (HO-1) and cyclooxygenase 2 (COX-2), and secretion of chemokines and prostaglandins after Rickettsia rickettsii infection of human cerebral, dermal, and pulmonary microvascular endothelial cells in comparison with ..
  38. Rydkina E, Sahni A, Silverman D, Sahni S. Rickettsia rickettsii infection of cultured human endothelial cells induces heme oxygenase 1 expression. Infect Immun. 2002;70:4045-52 pubmed
    ..defense mechanisms play a critical role in the host cell response during infection of endothelial cells by Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever...
  39. Joshi S, Francis C, Silverman D, Sahni S. Nuclear factor kappa B protects against host cell apoptosis during Rickettsia rickettsii infection by inhibiting activation of apical and effector caspases and maintaining mitochondrial integrity. Infect Immun. 2003;71:4127-36 pubmed
    ..The potentially fatal human infection caused by Rickettsia rickettsii, the etiologic agent of Rocky Mountain spotted fever, involves the vascular endothelium of various organ ..
  40. Woods M, Olano J. Host defenses to Rickettsia rickettsii infection contribute to increased microvascular permeability in human cerebral endothelial cells. J Clin Immunol. 2008;28:174-85 pubmed
    ..endothelial-target rickettsial infection using the etiological agent of Rocky Mountain spotted fever, Rickettsia rickettsii, and human cerebral microvascular endothelial cells. Endothelial cells infected with R...
  41. Piranda E, Faccini J, Pinter A, Pacheco R, Cançado P, Labruna M. Experimental infection of Rhipicephalus sanguineus ticks with the bacterium Rickettsia rickettsii, using experimentally infected dogs. Vector Borne Zoonotic Dis. 2011;11:29-36 pubmed publisher
    We evaluated if Rickettsia rickettsii-experimentally infected dogs could serve as amplifier hosts for hipicephalus sanguineus ticks. In addition, we checked if Rh. sanguineus ticks that acquired Ri...
  42. Piranda E, Faccini J, Pinter A, Saito T, Pacheco R, Hagiwara M, et al. Experimental infection of dogs with a Brazilian strain of Rickettsia rickettsii: clinical and laboratory findings. Mem Inst Oswaldo Cruz. 2008;103:696-701 pubmed
    The bacterium Rickettsia rickettsii is the etiological agent of an acute, severe disease called Rocky Mountain spotted fever in the United States or Brazilian spotted fever (BSF) in Brazil...
  43. Kidd L, Maggi R, Diniz P, Hegarty B, Tucker M, Breitschwerdt E. Evaluation of conventional and real-time PCR assays for detection and differentiation of Spotted Fever Group Rickettsia in dog blood. Vet Microbiol. 2008;129:294-303 pubmed publisher
    ..They may also facilitate the discovery of novel SFG Rickettsia infecting dogs, and in the investigation of dogs as sentinels for emerging rickettsioses...
  44. Houhamdi L, Raoult D. Experimentally infected human body lice (pediculus humanus humanus) as vectors of Rickettsia rickettsii and Rickettsia conorii in a rabbit model. Am J Trop Med Hyg. 2006;74:521-5 pubmed
    ..Although the body louse is not a known vector of spotted fevers, it was able in our study to acquire, maintain, and transmit both R. rickettsii and R. conorii...
  45. Joshi S, Francis C, Silverman D, Sahni S. NF-kappaB activation suppresses host cell apoptosis during Rickettsia rickettsii infection via regulatory effects on intracellular localization or levels of apoptogenic and anti-apoptotic proteins. FEMS Microbiol Lett. 2004;234:333-41 pubmed
    b>Rickettsia rickettsii, a gram-negative and obligate intracellular bacterium, is the causative agent of Rocky Mountain spotted fever. In human infections, the primary target of R. rickettsii infection is vascular endothelium...
  46. Stromdahl E, Jiang J, Vince M, Richards A. Infrequency of Rickettsia rickettsii in Dermacentor variabilis removed from humans, with comments on the role of other human-biting ticks associated with spotted fever group Rickettsiae in the United States. Vector Borne Zoonotic Dis. 2011;11:969-77 pubmed publisher
    ..1%) were detected in a small number of samples, but no ticks were found positive for Rickettsia rickettsii, the agent of Rocky Mountain spotted fever (RMSF) until May 2009, when it was detected in one D...
  47. Harlander R, Way M, Ren Q, Howe D, Grieshaber S, Heinzen R. Effects of ectopically expressed neuronal Wiskott-Aldrich syndrome protein domains on Rickettsia rickettsii actin-based motility. Infect Immun. 2003;71:1551-6 pubmed
    ..Functional roles for these cytoskeletal regulatory proteins in actin-based motility of Rickettsia rickettsii have not been established...
  48. Gasser A, Birkenheuer A, Breitschwerdt E. Canine Rocky Mountain Spotted fever: a retrospective study of 30 cases. J Am Anim Hosp Assoc. 2001;37:41-8 pubmed
    ..Diagnostic criteria included a four-fold rise in antibody titer to Rickettsia rickettsii (R. rickettsii) (n=15) or a single R...
  49. Sahni S, Van Antwerp D, Eremeeva M, Silverman D, Marder V, Sporn L. Proteasome-independent activation of nuclear factor kappaB in cytoplasmic extracts from human endothelial cells by Rickettsia rickettsii. Infect Immun. 1998;66:1827-33 pubmed
    ..of NF-kappaB activation in cultured human umbilical vein endothelial cells consequent to infection with Rickettsia rickettsii, an obligate intracellular gram-negative bacterium and the etiologic agent of Rocky Mountain spotted fever ..
  50. Karpathy S, Dasch G, Eremeeva M. Molecular typing of isolates of Rickettsia rickettsii by use of DNA sequencing of variable intergenic regions. J Clin Microbiol. 2007;45:2545-53 pubmed
    b>Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever, is found throughout the Americas, where it is associated with different animal reservoirs and tick vectors...
  51. Demma L, Traeger M, Blau D, Gordon R, Johnson B, Dickson J, et al. Serologic evidence for exposure to Rickettsia rickettsii in eastern Arizona and recent emergence of Rocky Mountain spotted fever in this region. Vector Borne Zoonotic Dis. 2006;6:423-9 pubmed
    ..The outbreak was associated with Rickettsia rickettsii in an unexpected tick vector, the brown dog tick (Rhipicephalus sanguineus), which had not been previously ..
  52. Souza C, Moraes Filho J, Ogrzewalska M, Uchoa F, Horta M, Souza S, et al. Experimental infection of capybaras Hydrochoerus hydrochaeris by Rickettsia rickettsii and evaluation of the transmission of the infection to ticks Amblyomma cajennense. Vet Parasitol. 2009;161:116-21 pubmed publisher
    The present study evaluated the infection of capybaras (Hydrochoerus hydrochaeris) by Rickettsia rickettsii and their role as amplifier hosts for horizontal transmission of R. rickettsii to Amblyomma cajennense ticks...
  53. Eremeeva M, Dasch G, Silverman D. Evaluation of a PCR assay for quantitation of Rickettsia rickettsii and closely related spotted fever group rickettsiae. J Clin Microbiol. 2003;41:5466-72 pubmed
    ..fever rickettsia quantitative PCR assay (SQ-PCR) was developed for the detection and enumeration of Rickettsia rickettsii and other closely related spotted fever group rickettsiae...
  54. Kleba B, Clark T, Lutter E, Ellison D, Hackstadt T. Disruption of the Rickettsia rickettsii Sca2 autotransporter inhibits actin-based motility. Infect Immun. 2010;78:2240-7 pubmed publisher
    ..In a guinea pig model of infection, the Sca2 mutant did not elicit fever, suggesting that Sca2 and actin-based motility are virulence factors of spotted fever group rickettsiae...
  55. Cragun W, Bartlett B, Ellis M, Hoover A, Tyring S, Mendoza N, et al. The expanding spectrum of eschar-associated rickettsioses in the United States. Arch Dermatol. 2010;146:641-8 pubmed publisher
    Until recently, Rickettsia rickettsii was the only substantiated cause of tick-borne spotted fever group (SFG) rickettsiosis in humans in the United States...
  56. Galvâo M, Calic S, Chamone C, Mafra S C, Cesarino Filho G, Olano J, et al. Spotted fever rickettsiosis in Coronel Fabriciano, Minas Gerais State. Rev Soc Bras Med Trop. 2003;36:479-81 pubmed
    ..The serological results confirm the difficulty in the differential diagnosis of patients with symptoms of rickettsial diseases...
  57. Rydkina E, Silverman D, Sahni S. Activation of p38 stress-activated protein kinase during Rickettsia rickettsii infection of human endothelial cells: role in the induction of chemokine response. Cell Microbiol. 2005;7:1519-30 pubmed
    b>Rickettsia rickettsii, a Gram-negative and obligate intracellular bacterium, preferentially infects the vascular endothelium during human infections leading to inflammation and dysfunction...