99mTc]Annexin V-128 SPECT Monitoring of Splenic and Disseminated Listeriosis in Mice: a Model of Imaging Sepsis.

Abstract

Here, we evaluate [(99m)Tc]annexin V-128, an in vivo marker of apoptosis, for single photon emission computed tomography (SPECT) imaging of localization and antibiotic treatment of disseminated bacterial infection, using a well-described mouse model that employs bioluminescent Listeria monocytogenes. Sixteen groups of five mice in six separate experiments were infected with bioluminescent Listeria, and in vivo bioluminescence imaging (BLI) was performed each day, to assess the location and extent of infection and response to antibiotics. [(99m)Tc]annexin V-128 was then injected for SPECT imaging, and the two sets of images were correlated and validated. Signals from BLI and [(99m)Tc]annexin V-128 SPECT co-localized within the spleen and other organs including bone marrow, intestine, nasopharynx, and brain. Decreases in [(99m)Tc]annexin V-128 uptake and BLI signal within the spleen directly reflected the reduction of bacterial infection by ampicillin treatment. Tc-99m-Annexin V-128 uptake as observed by SPECT allowed for the detection of systemic listeriosis and ampicillin treatment in mice. [(99m)Tc]annexin V-128 should be further explored for the assessment of bacterial spread and antibiotic efficacy in patients with disseminated bacterial infection.