Tracking Bacterial Infection Dynamics in a Mouse Using Bioluminescence

Begin with a suspension of an attenuated strain of a pathogenic bacterium.

The attenuated strain displays reduced pathogenicity due to targeted deletions in virulence genes.

The bacteria are chromosomally labeled with a bioluminescent operon that enables autonomous light production.

The bacteria express the bioluminescent operon, producing a luciferase enzyme and an enzyme complex that synthesizes the luciferase substrate.

Luciferase oxidizes the substrate to produce visible light.

Centrifuge the suspension and discard the supernatant.

Wash the cells with a buffer, centrifuge again, and discard the supernatant to remove residual non-cellular components.

Resuspend the cells in the buffer to achieve an optimal bacterial concentration and draw the suspension into a syringe.

Inject the suspension intraperitoneally into a mouse, then transfer it to a cage.

Visualize the bioluminescent signal at regular intervals.

The attenuated strain remains localized, and the bioluminescence gradually decreases, indicating clearance of infection.

On the morning of injections, thaw the cryovials of bacterial cells at four degrees Celsius for three to four hours. Keep the vials on ice after thawing and inject the