Cultures of urine samples collected from catheters compared with those obtained by direct Supra-pubic aspiration

Abstract

To examine the validity of cultures of fluid collected through drainage catheters, we reviewed retrospectively fluid specimens that had been collected through catheters in place for at least 2 days. These specimens were taken from patients at a large tertiary-care hospital. A total of 150 specimens representing 75 patients were collected as 2 samples from each patient, one sample is collected from drainage catheters and the other is collected directly as a supra-pubic aspiration. For 50 (67%) episodes there was no reliable imaging evidence for renal infection (UTI), making the results uninterpretable. The remaining 25 (33%) episodes were with infection. In 56% of cases, matched culture results were equivalent for therapeutic decisions. We conclude that direct aspiration of potentially infected fluid collections is the most reliable method of obtaining specimens for culture that should be used to guide therapy.