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PCR-based tests for the early diagnosis of sepsis. Where do we stand?
Andrew N Ginn1, Catriona L Halliday, Abby P Douglas
1aCentre for Infectious Diseases and Microbiology Laboratory Services, NSW Health PathologybCentre for Infectious Diseases and Microbiology, Westmead Institute for Medical Research, Westmead HospitalcThe Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South WalesdDepartment of Infectious Diseases, Peter MacCallum Cancer Centre, University of Melbourne, Melbourne, Victoria, Australia.
Insights
Early diagnosis of bloodstream infections using polymerase chain reaction (PCR) methods can significantly reduce mortality. PCR directly from blood samples offers rapid results, guiding timely antimicrobial therapy and preventing organ dysfunction in high-risk patients.
Area of Science:
- Clinical microbiology
- Infectious diseases
- Molecular diagnostics
Background:
- Bloodstream infections (BSIs) are a significant cause of hospital and ICU admissions, associated with high morbidity and mortality.
- Early and targeted antimicrobial therapy is crucial for reducing mortality in high-risk patients with BSIs.
- Prompt diagnosis and treatment are essential to prevent organ dysfunction.
Purpose of the Study:
- To review the role of PCR-based approaches in the early diagnosis of bloodstream infections.
- To highlight the potential of rapid molecular diagnostics for timely antimicrobial treatment.
- To discuss the clinical impact of early pathogen identification in sepsis management.
Main Methods:
- Focus on PCR-based diagnostic methods for bloodstream infections.
- Evaluation of highly multiplexed PCR systems for simultaneous detection of bacterial and fungal pathogens.
- Comparison of PCR directly from blood with traditional culture-based methods.
Main Results:
- Highly multiplexed PCR systems can provide results within 4-8 hours of blood draw, enabling rapid clinical decisions.
- PCR directly from blood offers advantages over culture methods, including independence from prior antibiotic therapy.
- While generally faster, PCR methods may exhibit lower sensitivity and specificity compared to post-culture detection.
Conclusions:
- Rapid and accurate identification of sepsis pathogens directly from blood samples is essential for improving patient outcomes.
- Nucleic acid detection assays, particularly PCR, are key for early pathogen identification at the time of patient presentation.
- The choice of PCR system depends on local epidemiology and laboratory resources.
Purpose Of Review:
Bloodstream infections are a major cause of hospital and ICU admission with high morbidity and mortality; however, early and targeted antimicrobial therapy reduces mortality in high-risk patients. This article focuses on the diagnosis of bloodstream infections by PCR-based approaches at an early stage to enable prompt treatment and prevent organ dysfunction.
Recent Findings:
PCR systems offering highly multiplexed targeting of bacterial and/or fungal pathogens (in whole blood) offer the best opportunity for clinical impact, as informed decisions can be made within 4-8 h of the blood draw. Although more rapid, these systems are typically associated with lower sensitivity and specificity than postculture detection methods which rely on microbial growth. Additionally, unlike postculture methods, detection directly from blood is not prone to misleading results because of concurrent (or previous) therapy, which limit clinical relevance.
Summary:
Rapid and accurate identification of the cause of sepsis is essential in improving patient outcomes. Early identification of these pathogens by nucleic acid detection assays directly from blood samples remains key to achieving this, particularly if taken at the time of presentation. Selection of the most suitable PCR system is typically influenced by local epidemiology and by the resources of the testing laboratory.
