Bacterial thymidine kinase as a non-invasive imaging reporter for Mycobacterium tuberculosis in live animals

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Abstract

Background: Bacteria can be selectively imaged in experimentally-infected animals using exogenously administered 1-(2′deoxy-2′- fluoro-β-D-arabinofuranosyl)-5- [125I]-iodouracil ([125I]-FIAU), a nucleoside analog substrate for bacterial thymidine kinase (TK). Our goal was to use this reporter and develop non-invasive methods to detect and localize Mycobacterium tuberculosis. Methodology/Principal Findings: We engineered a M. tuberculosis strain with chromosomally integrated bacterial TK under the control of hsp60 - a strong constitutive mycobacterial promoter. [125I]FIAU uptake, antimicrobial susceptibilities and in vivo growth characteristics were evaluated for this strain. Using single photon emission computed tomography (SPECT), M. tuberculosis Phsp60 TK strain was evaluated in experimentally-infected BALB/c and C3HeB/FeJ mice using the thigh inoculation or low-dose aerosol infection models. M. tuberculosis Phsp60 TK strain actively accumulated [125I]FIAU in vitro. Growth characteristics of the TK strain and susceptibility to common anti-tuberculous drugs were similar to the wild-type parent strain. M. tuberculosis Phsp60 TK strain was stable in vivo and SPECT imaging could detect and localize this strain in both animal models tested. Conclusion: We have developed a novel tool for non-invasive assessment of M. tuberculosis in live experimentally-infected animals. This tool will allow real-time pathogenesis studies in animal models of TB and has the potential to simplify preclinical studies and accelerate TB research.

Original languageEnglish (US)
Article numbere6297
JournalPloS one
Volume4
Issue number7
DOIs
StatePublished - Jul 16 2009

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ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)
  • General

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