Specific Imaging of Bacterial Infection Using 6″-¹⁸F-Fluoromaltotriose: A Second-Generation PET Tracer Targeting the Maltodextrin Transporter in Bacteria

Abstract

6″-¹⁸F-fluoromaltotriose is a PET tracer that can potentially be used to image and localize most bacterial infections, much like ¹⁸F-FDG has been used to image and localize most cancers. However, unlike ¹⁸F-FDG, 6″-¹⁸F-fluoromaltotriose is not taken up by inflammatory lesions and appears to be specific to bacterial infections by targeting the maltodextrin transporter that is expressed in gram-positive and gram-negative strains of bacteria. <b>Methods:</b> 6″-¹⁸F-fluoromaltotriose was synthesized with high radiochemical purity and evaluated in several clinically relevant bacterial strains in cultures and in living mice. <b>Results:</b> 6″-¹⁸F-fluoromaltotriose was taken up in both gram-positive and gram-negative bacterial strains. 6″-¹⁸F-fluoromaltotriose was also able to detect <i>Pseudomonas aeruginosa</i> in a clinically relevant mouse model of wound infection. The utility of 6″-¹⁸F-fluoromaltotriose to help monitor antibiotic therapies was also evaluated in rats. <b>Conclusion:</b> 6″-¹⁸F-fluoromaltotriose is a promising new tracer that has significant diagnostic utility, with the potential to change the clinical management of patients with infectious diseases of bacterial origin.