[Catalase test (Uriscreen) in the detection of bacteriuria-candiduria in hospitalized adults with Foley catheter].

BACKGROUND

Most urinary pathogens have the catalase enzyme, which has been used recently for detection of bacteriuria-candiduria, by an economic reaction in a tube containing 10% hydrogen peroxide and a catalyzer (Uriscreen). It has not been studied in patients with indwelling urinary catheter.

OBJECTIVE

To determine the accuracy of the catalase test (CT) in hospitalized patients with indwelling urinary catheters and to compare it against other rapid tests (nitrites and pyuria detection).

METHODS

The gold standard was the culture of urine, with 10(3) colony-forming units/mL as the threshold for significant growth. The nitrite test was determined by dipstick. The pyuria was determined by dipstick and microscopic examination.

RESULTS

Of 108 cultures from 57 patients, 62 were positives (57.4%). The values of accuracy of the CT were (%): sensitivity 88.5, specificity 42.6, predictive positive value 66.7, and predictive negative value 74.1. Compared against nitrites detection the CT showed higher sensitivity and specificity. Against pyuria detection, it showed higher sensitivity, but lower specificity.

CONCLUSIONS

Our study complements medical literature as it is the first focused in patients with indwelling catheter. The clinical use of the CT is limited and not superior to pyuria detection in this setting. However, because of its high sensitivity and low cost, it could be recommended for ruling out bacteriuria-candiduria in selected patients. A negative CT may prevent the need for expensive cultures.