The antibacterial effect of the bladder surface: an electron microscopic study

Area of Science:

• Urology
• Microbiology
• Cell Biology

Background:

• The urinary bladder possesses intrinsic defense mechanisms against bacterial infection.
• Understanding how the bladder prevents pathogen colonization is crucial for urological health.

Purpose of the Study:

• To investigate the interaction between Escherichia coli and the bladder's luminal surface.
• To elucidate the role of bladder microplicae and voiding in preventing bacterial adhesion and infection.

Main Methods:

• Utilized scanning and transmission electron microscopy to examine Escherichia coli and polystyrene latex spheres interacting with the vesical luminal surface.
• Observed the behavior of bacteria and particles within bladder folds during simulated voiding (bladder contraction).

Main Results:

• Bacteria and particles were observed to be held within folds of the cellular luminal surface.
• Voiding led to the entrapment of numerous bacteria and particles by microplicae, with subsequent engulfment into sub-surface vesicles.
• The presence of urine within folds and vesicles likely contributes to reducing residual urine volume.

Conclusions:

• Fixation of bacteria to the bladder mucosa is an initial step in the bladder's defense against infection.
• The bladder's intrinsic defense mechanism involves physical entrapment and removal of bacteria during voiding.
• Leukocytes appear to play a minimal role in the immediate defense against acute infection in a normal bladder model.