MRI-Contrast Agents for Detection of Bacterial Infection

Ania Warczyk^1,2, Anatoliy Popov², Stephen Pickup², Ari Goldberg², E. James Delikatny²

We report two MRI-compatible gadolinium contrast agents that selectively bind bacterial cell membranes allowing for the detection of bacteria with high sensitivity and specificity. The compounds combine a macrocyclic DOTA chelator linked to a moiety that binds bacterial surface lipids with high affinity. Incubation with the targeted contrast agents is shown to significantly increase R1 relaxation rates in cultures of E. coli, in contrast to conventional gadolinium contrast agents that can easily be washed out. The ability to noninvasively identify pathogenic bacterial sources would potentially aid in the diagnosis and treatment of systemic bacteremia.