Extracellular RNA or exRNA from bacteria can persist in disinfected drinking water. Scientists have found that analysing this RNA can reveal what bacteria were doing just before they were damaged or killed. This may help identify bacterial survival strategies and support the design of more effective disinfectants. The finding also adds to the wider understanding of exRNA as a stable biological signal outside cells.
What is extracellular RNA?
exRNA is RNA found outside cells in body fluids such as blood, saliva, urine and cerebrospinal fluid. Earlier, RNA was thought to function only inside cells. It was also assumed that any RNA leaking out would be rapidly destroyed by enzymes. Later research showed that cells can intentionally export RNA.
How exRNA survives outside cells
To remain stable, exRNA is carried in molecular containers that protect it from enzymatic breakdown. These containers allow RNA to travel through body fluids and reach target cells. This makes exRNA part of a long-distance communication system in the body.
Why exRNA matters in biology and medicine
Cells use exRNA to send instructions to other cells and alter their behaviour or gene activity. This helps regulate immune responses, tissue repair and development. Cancer cells can also use exRNA to support tumour growth. In medicine, exRNA has become useful as a biomarker. Blood and other body-fluid tests can detect RNA patterns linked to cancer and heart disease.
Significance for water treatment and public health
The new study shows that bacterial exRNA can remain detectable even after disinfection. This gives scientists a tool to study bacterial stress responses in water systems. It may help improve disinfectant methods and strengthen drinking water safety.
Last Modified: April 29, 2026