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Updated: May 6, 2026
Author Spotlight: Addressing Regulatory Gaps in Molecular Studies by Quantifying Viral Vectors in Complex Matrices
Published on: July 14, 2023
Development and evaluation of a PMA-ddPCR for accurate detection of viable hypervirulent Klebsiella pneumoniae
Zhiyu Li1, Minjie Yang2, Hongwen Duan1
1College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, China.
Background:
The global prevalence of hypervirulent Klebsiella pneumoniae (hvKP) infection is rising. Its high virulence, transmissibility, and propensity to enter the viable but non-culturable (VBNC) state compromise the accuracy of traditional culture methods, while standard molecular assays fail to differentiate between viable and dead bacteria, posing a challenge for clinical diagnosis.
Objective:
This study aimed to develop a novel detection method combining propidium monoazide (PMA) with droplet digital PCR (ddPCR) for sensitive, specific, and absolute quantification of viable hvKP cells.
Methods:
PMA was used to selectively inhibit the amplification of DNA from dead bacteria, combined with ddPCR for absolute quantification. The specificity, sensitivity, and detection performance in artificially spiked blood plasma samples were systematically evaluated, and the method was compared with PMA-qPCR.
Conclusions:
The PMA-ddPCR method successfully established in this study effectively distinguished viable from dead bacteria, with a limit of detection as low as 6.878 CFU/mL in blood plasma samples. It demonstrated excellent performance in simulated clinical samples, providing a reliable technical solution for the accurate detection of viable hvKP cells.
Insights
A new method using propidium monoazide (PMA) and droplet digital PCR (ddPCR) accurately detects viable hypervirulent Klebsiella pneumoniae (hvKP) bacteria. This approach overcomes limitations of traditional methods for improved clinical diagnosis.
Area of Science:
- Microbiology
- Molecular Biology
- Infectious Diseases
Background:
- Rising global prevalence of hypervirulent Klebsiella pneumoniae (hvKP) infections.
- hvKP's viable but non-culturable (VBNC) state challenges traditional culture methods.
- Standard molecular assays cannot distinguish between viable and dead bacteria, impacting clinical diagnosis.
Purpose of the Study:
- Develop a novel detection method for viable hvKP.
- Combine propidium monoazide (PMA) with droplet digital PCR (ddPCR).
- Achieve sensitive, specific, and absolute quantification of viable hvKP cells.
Main Methods:
- Utilized PMA to selectively inhibit DNA amplification from dead bacteria.
- Employed ddPCR for absolute quantification of viable bacteria.
- Evaluated specificity, sensitivity, and performance in spiked blood plasma samples, comparing with PMA-qPCR.
Main Results:
- Established a PMA-ddPCR method distinguishing viable from dead bacteria.
- Achieved a limit of detection as low as 6.878 CFU/mL in blood plasma.
- Demonstrated excellent performance in simulated clinical samples.
Conclusions:
- The PMA-ddPCR method provides a reliable solution for accurate detection of viable hvKP.
- Successfully differentiates viable from dead hvKP cells.
- Enhances clinical diagnosis accuracy for hvKP infections.
