The term "viable but nonculturable" (VBNC) refers to a state in which microorganisms, typically bacteria, are alive and capable of growth and metabolism, but they are unable to grow and divide under laboratory conditions that are generally used to culture bacteria. In other words, they are dormant or in a state of low metabolic activity that makes them difficult to detect and study using conventional laboratory techniques.
The VBNC state is often induced in response to unfavorable environmental conditions such as nutrient limitation, high or low temperatures, presence of toxic substances or desiccation. In this state, the bacteria can modify their cell morphology, reduce their metabolic rate, and exhibit increased resistance to environmental stresses.
One notable characteristic of VBNC bacteria is their ability to regain culturability once the favorable conditions are restored. This means that even though they cannot be cultured in the laboratory, they can still pose a potential risk for public health or other processes where bacteria are involved.
Detection and quantification of VBNC bacteria is challenging due to their low metabolic activity and reduced growth. Researchers use various techniques like DNA-based methods, flow cytometry, and microscopic techniques to identify and quantify VBNC bacteria in environmental samples.
Understanding the mechanisms and conditions that induce and regulate the VBNC state is important for public health, food safety, and environmental monitoring, as these dormant bacteria can resuscitate and resume their activity, potentially causing infections or other adverse effects.
