Impact of ddPCR panel implementation on optimizing antimicrobial therapy management in critically ill patients with bloodstream infections.

BACKGROUND

Bloodstream infections (BSIs) represent a life-threatening complication in critically ill ICU patients. Rapid molecular diagnostic tools such as digital droplet PCR (ddPCR) may facilitate earlier targeted therapy, but their clinical impact on antimicrobial stewardship and patient outcomes remains inadequately characterized.

METHODS

This single-center, prospective cohort study enrolled ICU critically ill patients with confirmed BSIs between June 2021 and June 2024(ChiCTR2100047526). Patients were assigned to either a ddPCR-guided group, where antibiotic adjustments were made within 24 hours based on ddPCR results, or a standard-of-care group, where therapy was guided by conventional blood culture results. The primary outcome was 28-day mortality. Inverse probability of treatment weighting (IPTW) was used to adjust for potential confounding.

RESULTS

138 consecutive critically ill patients with BSIs were enrolled and assigned to either the ddPCR-guided group (n = 69) or the standard-of-care group (n = 69). DdPCR significantly reduced turnaround time compared to blood culture (median 0.3 days vs. 3.0 days; p < 0.001). Accordingly, the ddPCR-guided group achieved higher rates of optimal antibiotic therapy by 24 hours (94.2% vs. 46.4%; p < 0.001), antibiotic adjustments mainly involved vancomycin, caspofungin, and agents targeting multidrug-resistant organisms (MDROs). Although optimization rates equalized by day 5 and there was no significant difference in 28-day mortality between the two groups, ddPCR guidance was associated with significantly lower in-hospital mortality (36.2% vs. 55.1%; p = 0.026), particularly in patients with Gram-negative bacteremia (33.3% vs. 66.7%; p = 0.005), Gram-negative multidrug-resistant organism bacteremia (40.9% vs. 87.5%; p = 0.006), and persistent BSIs (34.2% vs. 72.0%; p = 0.003). After IPTW adjustment, standard-of-care management was associated with an increased in-hospital mortality rate compared with ddPCR-guided management (standard-of-care group vs. ddPCR-guided group: IRR = 1.46, 95% CI: 1.01-2.14, p = 0.045).

CONCLUSIONS

Integrating ddPCR into routine ICU antimicrobial stewardship significantly shortened time to optimal therapy and improved survival, especially in high-risk BSI subgroups.