Imaging bacterial infections with radiolabeled 1-(2′-deoxy-2′- fluoro-β-D-arabinofuranosyl)-5-iodouracil

Bacterial infections provide diagnostic dilemmas that could be enlightened by modern imaging technologies. We have developed a simple method for imaging bacterial infections in mice that relies on the phosphorylation and trapping of the thymidine kinase (TK) substrate 1-(2′-deoxy-2′-fluoro-β-D- arabinofuranosyl)-5-[¹²⁵I] iodouracil ([¹²⁵I]FIAU) within bacteria. FIAU was found to inhibit the growth of WT Escherichia coli but not a TK^- strain, indicating that WT E. coli could metabolize this compound. In silico analyses demonstrated that all pathogenic strains of bacteria whose genomes have been sequenced contain a TK gene highly homologous to the E. coli TK. Accordingly, we demonstrated that localized infections caused by representatives of five genera of bacteria could be readily imaged with [¹²⁵I]FIAU. Such imaging provides a general method for the diagnosis of localized bacterial infections that could be translatable to the clinic.