Droplet digital PCR-Guided antibiotic use for critically ill patients with bloodstream infections: a retrospective observational study

BACKGROUND: Bloodstream infections (BSIs) cause substantial morbidity and mortality in critically ill patients. Conventional blood cultures (BCs) have limited sensitivity and long turnaround times, often leading to empirical broad-spectrum antibiotic use. Droplet digital PCR (ddPCR) enables rapid and sensitive pathogen detection, but its impact on antimicrobial decision-making remains unclear. METHODS: This retrospective observational study included adult ICU patients with suspected BSIs from October 2020 to August 2024. Diagnostic performance and turnaround time of ddPCR were compared with BCs. The influence of ddPCR results on antimicrobial therapy and clinical outcomes, including 28-day mortality and SOFA scores, were evaluated. RESULTS: Among 201 patients, 28-day mortality was 40.3%. ddPCR demonstrated a higher positivity rate than BCs (96.0% vs. 27.4%, P < 0.001), detecting 325 pathogens, including multidrug-resistant organisms, with a turnaround time 8.57 hours shorter (P < 0.0001). Antimicrobial therapy was modified in 37.3% of patients based on ddPCR results. No significant differences were observed in 28-day mortality or SOFA scores. CONCLUSION: Droplet digital PCR has potential in the early detection of BSIs. Antibiotic treatment guided by ddPCR had no adverse effect on patient prognosis. KEYPOINTS: Droplet digital PCR guided treatment for BSIs.