[Ga]Ga-Ornibactin for complex Infection Imaging Using Positron Emission Tomography.

Bacteria from the complex are generally considered to be non-pathogenic to the healthy population. However, some of these species may cause serious nosocomial infections in immunocompromised patients; as such, it is essential to diagnose these infections rapidly so that adequate treatment can be initiated. We report here the use of a radiolabeled siderophore, ornibactin (ORNB), for positron emission tomography imaging. We successfully radiolabeled ORNB with gallium-68 with high radiochemical purity and proved that the resulting complex has optimal characteristics. In mice, the complex did not show excessive accumulation in organs and was excreted in the urine. We demonstrated that the [Ga]Ga-ORNB complex accumulates at the site of infection, including pneumonia, in two animal infection models. These results suggest that [Ga]Ga-ORNB is a promising tool for the diagnosis, monitoring, and evaluation of the therapeutic response to complex infection.