Urease-positive bacteriuria and obstruction of long-term urinary catheters.

Long-term urethral catheterization (greater than or equal to 30 days), a management technique for urinary incontinence, results in polymicrobial bacteriuria. We frequently found urease-producing bacteria: of 1,135 weekly urine specimens from 32 long-term-catheterized patients, 86% had urease-positive bacterial species at greater than or equal to 10(5) CFU/ml. The most common species were Proteus mirabilis and Morganella morganii, each found in over half the specimens. P. mirabilis, but not other urease-positive species, was significantly associated with the 67 obstructions observed in 23 patients. M. morganii had a more complex association and in some way may protect the catheter from obstruction.