A photoactivation-free viability PCR reagent for rapid, culture-independent detection of live bacteria

Rapid and reliable detection of viable bacteria is essential for protecting public health, monitoring water quality, ensuring food safety, and advancing clinical diagnostics. Conventional culture methods underestimate viable cells and require days to deliver results, while conventional PCR-based tests cannot distinguish viable (live) from non-viable (dead) organisms. Here, we describe a photoactivation-free viability PCR reagent that overcomes these limitations by selectively blocking PCR amplification from non-viable cells. Using <i>Legionella pneumophila</i>, a waterborne pathogen that causes severe pneumonia, we show that this method provides accurate, culture-independent measurements of viable bacteria in water samples within hours. Results align with culture-based methods while avoiding long delays and technical drawbacks of traditional approaches. By simplifying workflows and improving accuracy, this reagent offers a broadly applicable tool for detecting viable microbes, enabling faster interventions and supporting microbial testing across environmental, clinical, and industrial settings.