Imaging hypoxic injury sites using live bacteria

Certain strains of bacteria, such as E. coli, Salmonella, and Clostridium, selectively colonize and grow in tumors. We have demonstrated that E. coli and Salmonella spp are capable of targeting both primary tumors and metastases, a feature that has been exploited for tumor-selective drug delivery as well detection. To facilitate the monitoring of these strains in vivo, bacteria have been engineered to express bioluminescence or fluorescence reporter genes, which enabled investigators to track migration patterns and determine the fate of the bacteria in a manner that is simple, non-invasive and amenable to repeated observations.