Modified reporting of positive urine cultures to reduce treatment of catheter-associated asymptomatic bacteriuria (CA-ASB) among inpatients: a randomized controlled trial

Abstract

We conducted a randomized, unblinded superiority trial to determine if modified laboratory reporting of positive urine cultures (UC) increased the appropriateness of antibiotic treatment among catheterized inpatients. Efficacy outcome was treatment appropriateness. Safety outcomes included adverse events, bacteremia, and death. Between November 2018 and June 2019, 100 consecutive positive UCs were randomized to the standard report (SR) (bacterial count, identification and susceptibility) or modified report (MR) (standardized comment). Exclusion criteria were pregnancy, current antibiotic treatment, intensive care unit (ICU) or urology admission, or neutropenia. Current antibiotic treatment was excluded because their use may affect culture interpretation. True diagnosis of catheter-associated urinary tract infection (CA-UTI) or catheter-associated asymptomatic bacteriuria (CA-ASB) was based on published criteria and prospective chart review. Patients were followed for 7 days after reporting. Of 543 positive UC considered, 443 were excluded. The intention-to-treat (ITT) analysis included 100 UCs, while per protocol (PP) included 90. CA-ASB was diagnosed in 75% of all urines and 60% of these cases were treated with antibiotics. All CA-UTI cases were treated. There was a trend towards increased appropriate treatment (untreated CA-ASB + treated CA-UTI) in the MR than the SR: 31/54 (57.4%) vs 23/46 (50.0%), (+7.4%, p=0.45, RR=1.15) by ITT analysis. PP analysis gave similar results. There were 4/54 (7.4%) deaths and 16/54 (29.6%) adverse events in the MR, and 3/46 (6.5%) deaths and 19/46 (41.3%) adverse events in the SR (-11.7% adverse events, p=0.216). We conclude that MR trends towards treatment appropriateness and may be safe. Larger studies are required.