Bacteriophage-based live bacteria detection for rapid infection diagnosis

Area of Science:

• Microbiology
• Molecular Biology
• Infectious Diseases

Background:

• Bacterial bloodstream infections (BSIs) are a major cause of morbidity and mortality.
• Current culture-based methods for bacterial identification are time-consuming, delaying critical treatment.
• The long diagnostic time of culture methods can reduce bacterial load, hindering accurate detection.

Purpose of the Study:

• To develop a rapid and direct method for detecting live bacteria in clinical samples.
• To overcome the limitations of traditional culture methods in terms of speed and sensitivity.
• To enable faster diagnosis and initiation of appropriate treatment for BSIs.

Main Methods:

• A novel method combining bacteriophage-based lysis with quantitative PCR (qPCR) was developed.
• Escherichia coli K12 (E. coli K12) was used as a model organism, lysed by a specific bacteriophage.
• The method was validated using bacteria spiked into reference plasma samples, bypassing pre-concentration and DNA extraction.

Main Results:

• The combined bacteriophage lysis-qPCR method achieved bacterial detection in under 3 hours.
• Only live bacterial cells were selectively lysed, ensuring specificity.
• Detection of bacterial DNA via qPCR in spiked plasma samples yielded consistent results with cultured bacteria (92-102.7% similarity).
• The limit of detection (LOD) and limit of quantification (LOQ) for spiked plasma were 14.80 CFU/mL and 3.5x10³ CFU/mL, respectively.

Conclusions:

• The bacteriophage lysis-qPCR method offers a simple, rapid, and selective approach for detecting live bacteria.
• This technique has the potential to significantly improve the diagnosis of bacterial bloodstream infections.
• Faster detection can lead to earlier clinical intervention and improved patient outcomes.