Which statement best reflects the cause of encrustation on catheters as described?

Which statement best reflects the cause of encrustation on catheters as described?

• A. Concentrated urine with glucose
• B. Urine colonized by urease-producing bacteria
• C. Acidic urine
• D. Prolonged catheterization

Answer: (B)

Encrustation on catheters occurs when urine is colonized by bacteria that produce the enzyme urease. Urease breaks down urea into ammonia and carbon dioxide, making the urine more alkaline. That alkaline environment shifts minerals like magnesium, ammonium, and phosphate to precipitate as crystals on the catheter surface (often forming struvite), leading to encrustations that can block the catheter. The crucial point is the urease activity from bacteria in the urine, not simply the duration of catheter use or the urine’s concentration. Acidic urine does not promote this crystallization, and concentrated urine with glucose isn’t the driving factor in this mechanism.

Encrustation on catheters occurs when urine is colonized by bacteria that produce the enzyme urease. Urease breaks down urea into ammonia and carbon dioxide, making the urine more alkaline. That alkaline environment shifts minerals like magnesium, ammonium, and phosphate to precipitate as crystals on the catheter surface (often forming struvite), leading to encrustations that can block the catheter. The crucial point is the urease activity from bacteria in the urine, not simply the duration of catheter use or the urine’s concentration. Acidic urine does not promote this crystallization, and concentrated urine with glucose isn’t the driving factor in this mechanism.