Development of three quantitative real-time PCR assays for the detection of Rickettsia raoultii, Rickettsia slovaca, and Rickettsia aeschlimannii and their validation with ticks from the country of Georgia and the Republic of Azerbaijan

Ju Jiang, Brian J. You, Evan Liu, Anisha Apte, Tamasin R. Yarina, Todd E. Myers, John S. Lee, Stephen C. Francesconi, Monica L. O'Guinn, Nikoloz Tsertsvadze, Nino Vephkhvadze, Giorgi Babuadze, Ketevan Sidamonidze, Maka Kokhreidze, Marina Donduashvili, Tinatin Onashvili, Afrail Ismayilov, Nigar Agayev, Mubariz Aliyev, Nizam MuttalibovAllen L. Richards

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

Abstract

A previous surveillance study of human pathogens within ticks collected in the country of Georgia showed a relatively high infection rate for Rickettsia raoultii, R. slovaca, and R. aeschlimannii. These 3 spotted fever group rickettsiae are human pathogens: R. raoultii and R. slovaca cause tick-borne lymphadenopathy (TIBOLA), and R. aeschlimannii causes an infection characterized by fever and maculopapular rash. Three quantitative real-time polymerase chain reaction (qPCR) assays, Rraoul, Rslov, and Raesch were developed and optimized to detect R. raoultii, R. slovaca, and R. aeschlimannii, respectively, by targeting fragments of the outer membrane protein B gene (ompB) using species-specific molecular beacon or TaqMan probes. The 3 qPCR assays showed 100% specificity when tested against a rickettsiae DNA panel (n= 20) and a bacteria DNA panel (n= 12). The limit of detection was found to be at least 3 copies per reaction for all assays. Validation of the assays using previously investigated tick nucleic acid preparations, which included Rickettsia-free tick samples, tick samples that contain R. raoultii, R. slovaca, R. aeschlimannii, and other Rickettsia spp., gave 100% sensitivity for all 3 qPCR assays. In addition, a total of 65 tick nucleic acid preparations (representing 259 individual ticks) collected from the country of Georgia and the Republic of Azerbaijan in 2009 was tested using the 3 qPCR assays. R. raoultii, R. slovaca, and R. aeschlimannii were not detected in any ticks (n= 31) from the Republic of Azerbaijan, but in the ticks from the country of Georgia (n= 228) the minimal infection rate for R. raoultii and R. slovaca in Dermacentor marginatus was 10% and 4%, respectively, and for R. aeschlimannii in Haemaphysalis sulcata and Hyalomma spp. it was 1.9% and 20%, respectively.

Original languageEnglish (US)
Pages (from-to)327-331
Number of pages5
JournalTicks and Tick-borne Diseases
Volume3
Issue number5-6
DOIs
StatePublished - Dec 2012
Externally publishedYes

Keywords

  • Quantitative real-time PCR assays
  • R. aeschlimannii
  • R. raoultii
  • R. slovaca
  • The country of Georgia

ASJC Scopus subject areas

  • Parasitology
  • Microbiology
  • Insect Science
  • Infectious Diseases

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