Effect of urine reflex culturing on rates of cultures and infections in acute and long-term care

Abstract

Background Urine cultures are often positive in the absence of a urinary tract infection (UTI). Pyuria is generally considered necessary to diagnose a UTI. Problem Urine cultures are often positive in the absence of UTI leading to unnecessary antibiotics. Methods Quasi-experimental pre-post study of all patient urine cultures ordered in a VA acute care hospital, emergency department (ED), and two long-term care (LTC) facilities from August 2016 to August 2018. Urine cultures performed per 100 days were compared pre- (August 2016 to July 2017) versus post-intervention (August 2017 to August 2018) using interrupted time series negative binomial regression. Intervention We examined whether reflexing to urine culture only if a urinalysis (UA) found greater than 10 WBC/hpf decreased urine culturing. Results In acute-care, reflex culturing resulted in a 39% time series regression analysis adjusted decrease in the rate of cultures performed (pre-intervention, 3.6 cultures/100 days vs. Post-intervention, 1.8 cultures/100 days, p < 0.001). Pre-intervention, 29% (4/14) of Catheter-associated UTI (CAUTI) would not have been reported if reflex culturing was employed. In the ED, reflex culturing was associated with a 38% (p = 0.0015) regression analysis adjusted decrease in cultures, from 5.4/100 visits to 3.3/100 visits. In LTC, there was a small absolute, but regression analysis adjusted increase of 89% (p = 0.0018) in rates from (0.4/100 days to 0.5/100 days). Conclusion In acute care and ED, urine reflex culturing decreased the number of urine cultures performed. A small absolute increase was seen between pre-post time periods in LTC. Reflex testing generally decreases cultures and may lead to more accurate diagnoses of CAUTI.

Quality Improvement Interventions and Implementation Strategies for Urine Culture Stewardship in the Acute Care Setting: Advances and Challenges

“…Recent surveys of academic and community hospitals revealed more than half of surveyed hospital laboratories offer reflex urine cultures [28,29]. Use of reflex urine cultures has resulted in a decline in urine cultures and CAUTI rates in many acute care hospitals, emergency departments, and long-term care facilities [30][31][32][33][34][35]. Similarly, use of stricter UA criteria for reflexing to culture resulted in a 45% reduction in the urine cultures ordered at the University of North Carolina Health System [36].…”

Applying Diagnostic Stewardship to Proactively Optimize the Management of Urinary Tract Infections

“…RUC has been shown to reduce rates of urine cultures, ASB, and antimicrobial use with no increase in Gram-negative blood stream infections in quasi-experimental and single center studies [55][56][57][58][59][60][61]. One benefit of RUC programs is that it has been implemented and studied in a variety of settings including the emergency department, hospitals (including intensive care units), long-term care, and ambulatory clinics.…”

“…The most used cutoffs were >5 WBC/HPF and >10 WBC/HPF. While some studies suggest higher pyuria cut-offs of >25WBC/HPF or >50 WBC/HPF may result in a larger decrease in the rate of urine cultures performed, such cut-offs are not well-studied [55,57].…”

“…While not as extensively studied, literature suggests that urinalysis is an acceptable method to effectively exclude a UTI as an infectious cause and reduce the rate of inappro-priate urine culturing in patients with indwelling urinary catheters [57,61,65,[68][69][70]. In the study carried out by Munigala and colleagues, there was an overall 45% reduction in urine cultures, but the effect was most marked for catheterized (75.6%) specimens compared to clean catch specimens (37.8%).…”

“…In the study carried out by Munigala and colleagues, there was an overall 45% reduction in urine cultures, but the effect was most marked for catheterized (75.6%) specimens compared to clean catch specimens (37.8%). Additionally, a urine reflex culturing protocol implemented across three VA medical centers would have reflexively cancelled 29% of urine cultures reducing the CAUTI rate from 1.82 infections per 1000 catheter days to 1.30 infections per 1000 catheter days [57]. Another large tertiary care hospital reported that a reflex urine culture protocol implemented in five ICU settings significantly decreased monthly urine culture (p < 0.001) and CAUTI rates (p = 0.04) for 12 months post-intervention [68].…”