This study investigates the internalization mechanism of uropathogenic bacteria in the urinary tract of male mice. The research highlights how these bacteria evade the immune response by forming intracellular bacterial communities (IBCs).
Take an anesthetized male mouse and insert a catheter into its genitalia.
Introduce uropathogenic bacteria into the urethra. Inside the urinary tract, the bacterium attaches to the uroepithelial cell.
The interaction of bacterial surface proteins with host cell membrane proteins induces cytoskeletal rearrangement causing the host cell membrane to tightly wrap around the bacterium through a zipper mechanism.
The bacterium is subsequently internalized within a membrane-bound vesicle. Within the vesicle, the bacterium produces α-hemolysin toxin monomers which assemble to form a pore complex in the vesicular membrane.
The bacterium escapes through the pore complex into the host cell cytoplasm where it replicates to form intracellular bacterial communities, or IBCs. IBCs are dense, biofilm-like structures within host cells, protected from direct attack by immune cells present in the extracellular space.
As the uropathogenic bacteria mature within IBCs, they eventually exit the host cells to infect neighboring cells, causing urinary tract infections.
To inoculate male mice, place two thumb forceps cranially and caudally to the mouse's external genitalia. Retract the prepuce to fully expose the glans penis. Then, once the penis is externally positioned, release the thumb forceps. Reposition the forceps to stabilize the protruding penis perpendicular to the animal, holding the organ gently but tautly. Then, through the small opening in the tip of the urethral meatus, carefully introduce the catheter and gently guide it into the penis using forceps to gently maintain tension.
Once the hub of the catheter meets the tip of the penis, very slowly, dispense 50 microliters of the inoculum while maintaining the position of the penis. Note the quality of the instillation according to a predetermined instillation quality score, such as the one shown here. Retract the catheter slowly over 5 seconds to prevent leakage of the inoculum. Place the mouse in its cage in a supine position. The animal should begin to recover 30 to 45 minutes following administration of the anesthetic.
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