Bioluminescent imaging of bacteria during mouse infection

Diagnostic imaging is a powerful tool that has recently been applied towards the study of infectious diseases. Optical imaging of bioluminescently labeled bacteria in infected animals allows for real-time analysis of bacterial proliferation and dissemination during infection without sacrificing the animal. Imaging also allows for tracking of disease progression in an individual subject over time, has the potential to reveal previously overlooked sites of infection, and reduces the number of research animals used in pathogenesis studies. Here, we describe the use of a deep-cooled CCD camera imager to record light emitted from bacteria during infection. We also describe the process of correlating bioluminescence to bacterial numbers by ex vivo imaging of necropsied tissues. Together these techniques can be used to estimate bacterial burdens in host tissues both in vivo and ex vivo using bioluminescent imaging.