Evaluation of a rapid, direct sample loading electrochemical AST assay with clinical urine samples

Phenotypic antibiotic susceptibility testing (AST) is essential, but conventional culture-based methods require 48-72 h, delaying targeted treatment. Here we report a first small study of a direct electrochemical AST system on clinical urine samples. The study aimed to validate the technology and support further research.

18 urine and 2 control samples were tested with 3 antibiotics above and below EUCAST breakpoints, resulting in 474 antibiotic-sample combinations grouped as 158 triplets.

Using routine clinical diagnostics as reference method, categorical agreement, sensitivity, and specificity were 87.9% (95% CI, 83.7-91.1%), 0.95 (95% CI, 0.8952-0.9769) and 0.831 (95% CI, 0.7684-0.8786), respectively. The average time to result was 6.0 ± 3.3 h. Its non-species-specific electrochemical principle theoretically allows it to be applied to various sample types and organisms.

These results demonstrate that the electrochemical AST platform provides accurate results on the same day directly from patient samples, likely eliminating the need for mandatory pre-culturing.