Volume 73, Issue 6
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645


A highly specific real-time polymerase chain reaction (PCR) assay was developed to detect spotted fever and typhus group rickettsiae using the citrate synthase gene as the target. The assay amplified rickettsial members of the spotted fever and typhus group including , , , , , , and . The ancestral group rickettsia, , did not produce a positive reaction, nor did other members of the order or any non-rickettsial bacteria. The assay had a sensitivity of one target copy number per reaction as determined by serial dilutions of a plasmid containing a spotted fever group target sequence. This quantitative assay is useful for the enumeration of rickettsiae in clinical specimens and the diagnosis of rickettsial illnesses, when rickettsial numbers are very low.


Article metrics loading...

Loading full text...

Full text loading...



  1. Andersson SG, Zomorodipour A, Andersson JO, Sicheritz-Ponten T, Alsmark UC, Podowski RM, Naslund AK, Eriksson AS, Winkler HH, Kurland CG, 1998. The genome sequence of Rickettsia prowazekii and the origin of mitochondria. Nature 396 : 133–140.
  2. Stothard DR, Clark JB, Fuerst PA, 1994. Ancestral divergence of Rickettsia bellii from the spotted fever and typhus groups of Rickettsia and antiquity of the genus Rickettsia. Int J Syst Bacteriol 44 : 798–804.
  3. Raoult D, Roux V, 1997. Rickettsioses as paradigms of new or emerging infectious diseases. Clin Microbiol Rev 10 : 694–719.
  4. Graves SR, Dwyer BW, McColl D, McDade JE, 1991. Flinders Island spotted fever: a newly recognised endemic focus of tick typhus in Bass Strait, Part 2: Serological investigations. Med J Aust 154 : 99–104.
  5. Unsworth NB, Stenos J, McGregor AR, Dyer JR, Graves SR, 2005. Not only ‘Flinders Island’ spotted fever. Pathology 37 : 242–245.
  6. Tzianabos T, Anderson BE, McDade JE, 1989. Detection of Rickettsia rickettsii DNA in clinical specimens by using polymerase chain reaction technology. J Clin Microbiol 27 : 2866–2868.
  7. Regnery RL, Spruill CL, Plikaytis BD, 1991. Genotypic identification of rickettsiae and estimation of intraspecies sequence divergence for portions of two rickettsial genes. J Bacteriol 173 : 1576–1589.
  8. Sexton DJ, Kanj SS, Wilson K, Corey GR, Hegarty BC, Vevy MG, Breitschwerdt EB, 1994. The use of a polymerase chain reaction as a diagnostic test for Rocky Mountain spotted fever. Am J Trop Med Hyg 50 : 59–63.
  9. Jiang J, Chan T-C, Temenak JJ, Dasch GA, Ching W-M, Richards AL, 2004. Development of a quantitative real-time polymerase chain reaction assay specific for Orientia tsutsugamushi. Am J Trop Med Hyg 70 : 351–356.
  10. Courtney JW, Kostelnik LM, Zeidner NS, Massung RF, 2004. Multiplex real-time PCR for detection of Anaplasma phagocytophilium and Borrelia burgdorferi. J Clin Microbiol 42 : 3164–3168.
  11. Jiang J, Temenak JJ, Richards AL, 2003. Real-time duplex assay for Rickettsia prowazekii and Borrelia recurrentis. Ann NY Acad Sci 990 : 302–310.
  12. Roux V, Rydkina E, Eremeeva M, Raoult D, 1997. Citrate synthase gene comparison, a new tool for phylogenetic analysis, and its application for the rickettsiae. Int J Syst Bacteriol 47 : 252–261.
  13. Davis LG, Dibner MD, Battey JF, 1986. Optical density analytical measurements. Basic methods in molecular biology. New York: Elsevier Science, 327–328.
  14. Rogall T, Wolters J, Flohr T, Böttger EC, 1990. Towards a phylogeny and definition of species at the molecular level within the genus Mycobacterium. Int J Syst Bacteriol 40 : 323–330.
  15. Kaplowitz LG, Lange JV, Fischer JJ, Walker DH, 1983. Correlation of rickettsial titers, circulating endotoxin, and clinical features in Rocky Mountain spotted fever. Arch Intern Med 143 : 1149–1151.
  16. Weinberg EH, Stakebake JR, Gerone PJ, 1969. Plaque assay for Rickettsia rickettsii. J Bacteriol 98 : 398–402.
  17. Stenos J, Graves S, Dwyer B, 1992. Quantification of Rickettsia australis. Am J Trop Med Hyg 47 : 141–146.
  18. Eremeeva ME, Dasch GA, Silverman DJ, 2003. Evaluation of a PCR assay for quantitation of Rickettsia rickettsii and closely related spotted fever group rickettsiae. J Clin Microbiol 41 : 5466–5472.
  19. Walker DH, Tidwell RR, Rector TM, Geratz JD, 1984. Effect of synthetic protease inhibitors of the amidine type on cell injury by Rickettsia rickettsii. Antimicrob Agents Chemother 25 : 582–585.
  20. Maurin M, Raoult D, 1997. Bacteriostatic and bactericidal activity of levofloxacin against Rickettsia rickettsii, Rickettsia conorii, ‘Israeli spotted fever group rickettsia’ and Coxiella burnetii. J Antimicrob Chemother 39 : 725–730.
  21. Kenyon RH, Sammons LS, Pedersen CE Jr, 1975. Comparison of three Rocky Mountain spotted fever vaccines. J Clin Microbiol 2 : 300–304.
  22. Fournier P-E, Gouriet F, Brouqui P, Lucht F, Raoult D, 2005. Lymphangitis-associated rickettsiosis, a new rickettsiosis caused by Rickettsia sibirica mongolotimonae: Seven new cases and review of the literature. Clin Infect Dis 40 : 1435–1444.

Data & Media loading...

  • Received : 14 Mar 2005
  • Accepted : 19 Aug 2005

Most Cited This Month

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error