What question did this study set out to answer?

To assess the impact of multiplex polymerase chain reaction on antibiotic decision-making in ICU patients with pneumonia.

February 28, 2026Open Access

Real-world experience using multiplex polymerase chain reaction in intensive care unit patients with hospital-acquired and ventilator-associated pneumonia in South Korea

Key Points

To assess the impact of multiplex polymerase chain reaction on antibiotic decision-making in ICU patients with pneumonia.
Retrospective study design involving ICU patients diagnosed with HAP or VAP
Conducted at a tertiary medical center from July 2023 to June 2024
All patients underwent both mPCR and respiratory culture for pathogen detection
Primary outcome measured was the time to first antibiotic modification
Secondary outcome measured was rate of antibiotic de-escalation based on mPCR results.
mPCR identified pathogens in 45.3% of cases with a median turnaround time of 281 minutes
Median time to antibiotic modification was significantly shorter for mPCR (5.8 hours) compared to culture (122.32 hours)
Antibiotic discontinuation was low despite negative mPCR results for gram-negative bacilli (4.2%) and Staphylococcus aureus (7.7%).

Abstract

Background: Hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) are common among critically ill patients, leading to increased morbidity and mortality rates. Conventional culture-based diagnostics require 48–72 hours, which delays pathogen identification and prolongs the use of broad-spectrum antibiotics. Multiplex polymerase chain reaction (mPCR) enables the rapid detection of pathogens and resistance genes, but its effects on real-world antibiotic decision-making remain unclear.Methods: This retrospective study included patients in the intensive care unit who were diagnosed with HAP or VAP at a tertiary medical center between July 2023 and June 2024. All patients underwent both mPCR and respiratory culture. The primary outcome was the time to the first antibiotic modification based on mPCR or respiratory culture. The secondary outcome was the rate of antibiotic de-escalation from carbapenem or teicoplanin/vancomycin based on mPCR findings.Results: In total, 75 patients were included (median age, 68 years; 61.3% male). mPCR identified bacterial pathogens in 45.3% cases, with a median turnaround time of 281 minutes. The median time to antibiotic modification was 5.8 hours for mPCR versus 122.32 hours for culture (P<0.01). Despite negative mPCR results for gram-negative bacilli, carbapenem therapy was discontinued in only 1 of 24 cases (4.2%). Among 39 patients with negative results for Staphylococcus aureus, vancomycin or teicoplanin was discontinued in only 3 cases (7.7%).Conclusions: mPCR provided faster pathogen identification and earlier antibiotic modifications than conventional respiratory culture. However, antibiotic discontinuation remained uncommon despite negative mPCR results, highlighting challenges in real-world antimicrobial stewardship.

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