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Relationship between Urease‐producing Bacteria, Urinary pH and Encrustation on Indwelling Urinary Catheters
Author(s) -
HEDELIN H.,
BRATT C.G.,
ECKERDAL G.,
LINCOLN K.
Publication year - 1991
Publication title -
british journal of urology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.773
H-Index - 148
eISSN - 1464-410X
pISSN - 0007-1331
DOI - 10.1111/j.1464-410x.1991.tb15200.x
Subject(s) - urinary system , urease , chemistry , urine , ammonium , phosphate , struvite , biochemistry , medicine , enzyme , organic chemistry
Summary— In 11 patients with long‐term indwelling catheters the amount of catheter encrustation and urinary pH were measured and the urine regularly cultured over a prolonged period of time (median of 7 periods of 3 weeks). The mean urinary pH was related to the persistent presence of urease‐producing micro‐organisms ( P. mirabilis ) and urinary pH governed the precipitation of catheter encrustation. The critical pH appeared to be around 6.8. In patients with a mean urinary pH below this level the encrustation was minute (≤2.9 mg phosphate). In patients with a mean urinary pH above 6.8 it was considerable but with a marked interindividual variation (35.5–138.7 mg phosphate). The composition of the encrustation was also strongly pH‐related, with a much higher proportion present as magnesium ammonium phosphate in patients with a mean urinary pH above 6.8. The persistent presence of urease producers was not associated with a high pH or a more pronounced precipitation of phosphate in all patients. The amount of encrustation thus appears to depend not only on the presence of urease‐producing micro‐organisms but also on individual factors such as urinary composition.