Automated urine culture system with reduced turnaround time: A prospective real-world evaluation

Background

Urinary tract infections are among the most common bacterial illnesses in clinical practice. Urine culture is the diagnostic reference standard for these infections, representing a major proportion of the workload of microbiological laboratories. Conventional urine cultures require 18-24 h of incubation and are negative in about 80.0 %. Uroquattro-HB&L® [Alifax] is an automated urine culture system providing results in 5 h.

Objectives

To evaluate the diagnostic performance of this rapid system compared to conventional culture and test its applicability for rapid identification and susceptibility testing in a real-world setting.

Methods

A total of 1,062 routine urine samples were included and tested in parallel by Uroquattro-HB&L rapid culture and by conventional culture. Uroquattro-HB&L performance was analyzed in comparison to conventional culture and a composite reference standard. Microorganisms from rapid culture were identified by MALDI-TOF technique. In a subset of 58 Uroquattro-HB&L-positive samples, a rapid susceptibility testing protocol was applied using the VITEK 2 XL system.

Results

Compared to conventional culture, Uroquattro-HB&L showed a sensitivity of 87.3 %, specificity of 91.1 %, accuracy of 90.5 %, and positive and negative predictive values of 64.9 % and 97.4 %, respectively. Using the composite reference standard, the sensitivity and specificity were 91.3 % and 100 %, respectively. Agreement between the identification results was 92.3 %. Rapid antimicrobial susceptibility testing showed >90.0 % concordance with conventional AST.

Conclusions

Uroquattro-HB&L accurately identified culture-negative urine samples and permitted the identification of positive samples within 4-5 h. The system was also used to obtain rapid susceptibility testing results; however, this application requires further evaluation.