Maltodextrins Image Early Stage Bacterial Infections and Drug Resistance by Positron Emission Tomography

Bacterial infections are a central cause of mortality in the world and affect all areas of medicine ranging from cardiology to oncology.  Bacterial infections remain a major health problem despite the availability of effective antibiotics, because their diagnosis is challenging and because they are frequently treated with ineffective antibiotics, due to the widespread rise of bacterial drug resistance.  In this report, we present a new PET contrast agent, composed of F-18 conjugated to maltohexaose (¹⁸F-MH), which can for the first time image bacteria in vivo with the specificity and sensitivity needed to detect early stage infections and measure drug resistance in vivo.  We show here that ¹⁸F-MH can detect as few as 10⁵ E.coli colony forming units (CFUs) in rats, which is 3-4 orders magnitude higher in sensitivity than FDG, the current clinically used bacterial infection contrast agent.   In addition, we demonstrate that ¹⁸F-MH can distinguish bacterial infections from inflammation, and has a specificity that is 2-3 orders of magnitude higher than FDG, giving it the potential to identify infections clinically without a biopsy.   Finally, we demonstrate that ¹⁸F-MH can monitor treatment efficacy in vivo and can identify beta lactam resistance in E.coli in real time, thus providing physicians with a powerful tool for guiding antibiotic selection.  We anticipate numerous clinical applications of ¹⁸F-MH given the widespread use of PET and the pervasiveness of infections in medicine.