Impact of combined molecular identification and rapid phenotypic drug antimicrobial susceptibility testing on the time to results for positive blood cultures – preliminary report

Introduction and aim: Rapid diagnosis of positive blood cultures supports earlier optimisation of antimicrobial therapy. This study assessed the impact of combined BioFire FilmArray BCID/BCID2 test from bioMérieux and molecular identification and rapid phenotypic antimicrobial susceptibility testing with dRAST on time to organism identification and to a complete microbiological result. Material and methods: This retrospective laboratory analysis included positive blood cultures from 30 independent patients, randomly selected from cultures obtained in the first half of 2025 at the Microbiology Department of the University Clinical Hospital in Opole. Turnaround times from collection to bottle loading, positivity signal, identification and complete result were analysed. Predefined pairwise comparisons used the Mann-Whitney test, and associations were assessed with Spearman rank correlation. Results: BCID/BCID2 was used in 15/30 cases, dRAST in 13/30, and the combined pathway in 11/30. The most frequent finding was Escherichia coli, including ESBL-positive isolates and one polymicrobial case (12/30; 40.0%), followed by Staphylococcus aureus (5/30; 16.7%). Median time from positivity signal to identification was 2.50 h with BCID/BCID2 and 24.00 h without BCID/BCID2 (p < 0.001). Median time from collection to a complete result was 26.00 h in the combined BCID/BCID2 with dRAST pathway and 69.50 h in the conventional pathway (p < 0.001). Conclusions: Combining BCID/BCID2 with rapid phenotypic AST using dRAST significantly shortened turnaround time to a complete positive blood culture result. The largest potential for time reduction was observed after the positivity signal.