Establishing a Mouse Model of Vaginal Group B Streptococcus Infection

Take a culture of Group B Streptococcus or GBS, an opportunistic bacterial pathogen.

Dilute the culture in fresh media and incubate to obtain actively dividing bacteria.

Transfer the culture to a conical tube.

Centrifuge to pellet the bacteria, then discard the supernatant.

Wash the bacteria with buffer.

Centrifuge again, remove the supernatant, and resuspend the bacteria in buffer.

Next, use a hormone-treated female mouse with a primed vaginal epithelium, more susceptible to infection.

Restrain the mouse. Using a fine pipette tip, dispense the GBS suspension into the vaginal lumen.

Release the mouse, lift its tail, and let the front paws walk on a firm surface.

This promotes inoculum retention in the vaginal lumen, enabling GBS adherence.

Inspect the vaginal opening for inoculum backflow.

The adhered bacteria colonize the vaginal epithelial surface and establish an infection.

The mouse model with vaginal infection is ready for further studies.

On the same day as the injection, grow a five milliliter, overnight liquid culture of the GBS strain of interest in Todd Hewitt broth, or THB, at 37 degrees Celsius.

The next morning, subculture the GBS at a 1 to 10 volume in fresh THB for a two to three