Acidification of Urine is not a Feasible Method for Preventing Encrustation of Indwelling Urinary Catheters

Abstract

Encrusting deposits form on urinary catheters as a result of infection by bacteria which produce urease. Urease catalyses the hydrolysis of urea to produce ammonia, with the result that the pH of the urine increases and the deposits are precipitated. It has been suggested that acidification of urine may prevent this rise in pH and so prevent encrustation. Experiments were performed in vitro to determine whether acidification could be used to prevent the rise in pH when urease is present in urine. It was found that, in the presence of urease, the initial decrease in pH resulting from acidification was countered by further urea being converted into ammonia. Thus, although acidic washout solutions may dissolve encrusting deposits, acidification of urine is not a feasible method for preventing catheter encrustation.

Keywords:

• acidification
• catheters
• encrustation
• urease
• urine