From Shadows to Spotlight: Enhancing Bacterial DNA Detection in Blood Samples through Cutting-Edge Molecular...

Area of Science:

• Molecular Diagnostics
• Infectious Disease Research
• Clinical Microbiology

Background:

• Detecting low-concentration DNA in biological samples is challenging for molecular diagnostics.
• Sample matrices and background DNA limit sensitivity and accuracy in molecular testing.
• High diagnostic sensitivity is critical for identifying bloodstream infections and sepsis.

Purpose of the Study:

• To develop a molecular method that bridges the gap between low analyte concentrations and diagnostic requirements.
• To enhance the sensitivity of pathogen detection in whole blood samples.
• To enable rapid, cultivation-independent identification of bacterial species and resistance markers.

Main Methods:

• Developed a sample preparation technique involving direct downstream pre-amplification of whole blood.
• Implemented a multiplex procedure to amplify specific bacterial species and resistance markers.
• Validated the method using blood samples spiked with Gram-positive and Gram-negative bacterial pathogens.

Main Results:

• Pre-amplification increased pathogen detection sensitivity in whole blood by up to 100-fold compared to non-pre-amplified samples.
• Achieved a detection limit of 1 colony-forming unit (CFU)/mL for *S. aureus* and *E. faecium*.
• Established detection limits of 28 CFU/mL for *E. coli* and 383 CFU/mL for *K. pneumoniae*.

Conclusions:

• The novel pre-amplification method significantly enhances molecular diagnostic sensitivity for bloodstream pathogens.
• This technique holds potential for accelerating sepsis diagnostics, potentially reducing mortality.
• Further validation in clinical samples from septic patients is warranted.