Micro-PET imaging of fluoroacetate combined with FDG to differentiate chronic Mycobacterium tuberculosis infection from an acute bacterial infection in a mouse model: A preliminary study

Mycobacterium tuberculosis (TB) infection is one of the deadliest infectious diseases worldwide and is responsible for 1.7 million deaths per year. The increase in multidrug-resistant TB poses formidable challenges to the global control of tuberculosis. TB infection could easily yield false-positive results in fluorine-18-fluorodeoxyglucose (FDG) PET imaging for cancer detection because of its high FDG uptake. We describe the combined FDG PET with fluorine-18-fluoroacetate (FAC), a promising analog of carbon-11-acetate, for targeting glycolysis and de novo lipogenesis, respectively, to determine the metabolic differences between chronic TB infection and acute infection.Materials and methodsSix-month-old BALB/c mice were inoculated with Mycobacterium bovis to induce chronic TB infection, and Escherichia coli as well as Staphylococcus aureus to induce acute infection for an in-vivo imaging study. Eighteen days after inoculation for chronic TB infection and 5 days for acute infection, both FDG and FAC micro-PET were performed on the infected mice. Analysis of variance and the Tukey honest ad-hoc test were carried out to determine differences among treatment with different bacterial infections.ResultsTB infection showed much lower FAC accumulation than acute infection. However, both TB infection and acute infection exhibited high FAC accumulation.ConclusionThe marked metabolic differences in de novo lipogenesis and glycolysis in FDG and FAC uptakes in micro-PET imaging, respectively, help to differentiate chronic TB infection from acute infection.