Diagnostic accuracy and clinical impact of filmarray multiplex PCR system in bloodstream infections: A comparative study with conventional methods in a tertiary health care setting.

The prompt identification of the causative microorganism responsible for bloodstream infections (BSIs) is paramount, as is the determination of its resistance profile. The aim of this study was to evaluate the diagnostic performance of the BioFire FilmArray Blood Culture Identification 2 (BCID2) panel for BSIs compared to conventional methods (CTMs) and its impact on antimicrobial treatment decisions. The study included 93 positive blood cultures from 85 patients with suspected BSI between January and August 2024. The BCID2 system demonstrated an accuracy of 90.32% in identifying positive samples in culture. The analytical sensitivity was calculated to be 83.72%, while the clinical sensitivity was determined to be 77.41% at the sample level. The highest concordance at the isolate level was observed for Klebsiella pneumoniae, Serratia marcescens, and Acinetobacter baumannii, with a 100% concordance rate. The compatibility of the method with conventional techniques was found in 85.13% of monomicrobial samples and 47.36% of polymicrobial samples. The mean time to result was determined as 1 day and 4 hours for BCID2 and 2 days and 4 hours for CTMs to identification; the difference was found to be significant. With regard to the detection of antimicrobial resistance genes, a 73.46% concordance was observed between BCID2 and conventional phenotypic methods at the sample level. While the presence of resistance was detected phenotypically in A. baumannii isolates, this could not be demonstrated genotypically with BCID2. In treatment simulations for antimicrobial stewardship, 91.5% of correct treatment arrangements were achieved according to the Norwegian guideline. Furthermore, an examination of the impact of gram stain pattern on diagnostic agreement revealed 90% agreement in anaerobic bottles, 77.77% in pediatric bottles, and 73.43% in aerobic bottles. However, these differences were not found to be statistically significant. Conversely, a significant difference in agreement rates was observed according to gram stain pattern, with 94.1% agreement observed in gram-positive cocci and 79.1% in gram-negative bacilli, yielding a statistically significant difference. BCID2 has the potential to improve clinical decision-making processes in the management of BSIs with its rapid diagnosis time, high specificity, and resistance detection capacity; however, due to its current limitations, it is currently best used as a supportive tool to CTMs.