Listeria monocytogenes, a deadly bacterium, can enter a dormant state when faced with environmental stress, making it undetectable by common tests. Scientists have discovered the mechanisms behind this dormancy and developed a new detection method, shedding light on bacterial survival strategies and opening up possibilities for better public health management. Listeria monocytogenes is a ubiquitous pathogen that can cause the serious disease listeriosis, with a mortality rate of up to 30% in humans.
The Dormant Deception
The bacterium Listeria monocytogenes, the causative agent of listeriosis, can switch into a dormant state when it encounters environmental stress — such as exposure to low doses of disinfectants and even starvation. These ‘viable but non-culturable’ (VBNC) bacteria, in their dormant state, are not able to grow again using standard tests for the food industry and hospitals.
The pathogenic bacteria can then enter a state of dormancy, but this poses an even greater risk to health because dormant bacteria, upon the sensation of a suitable environment, “wake up” and become virulent again. The detection tests, which are aimed at detecting the non-existence of microbes in hospitals or the agri-food sector, have always depended on the cultivation of microorganisms from a sample in microbiological laboratories. If no microorganisms show up in cultivation, the sample is deemed sterile. However, in the presence of the multiple stresses such environments commonly encounter, some bacteria exit from this state to become VBNC, including Listeria monocytogenes (15), and they may escape detection by these growth-based tests.
Getting to the Bottom of Dormancy
To elucidate its mechanisms better, Listeria monocytogenes were submitted to VBNC in mineral spring water (a low-nutrient environment) by a team of researchers from INRAE and Institut Pasteur. As the bacterium shifts to what happens to be VBNC, its original rod shape is lost and it becomes round, researchers found. The worldview is now very different because it has been fundamentally transformed from a cell with walls that define its shape and shield it to a naked blob.
Nevertheless, the dormant forms of the bacterium, while lacking a cell wall, remain uniquely resistant to physicochemical challenges that lead to changes in the composition or performance of their membrane and induce efficient stress responses by relying on a special multilayer assembly of proteins. Scientists created antibodies that can identify only in a dormant state to unite in Listeria monocytogenes bacteria, which additionally allows the growth of focused test detection.
Discussion and Future Directions
Our results show that the bacterial cell wall plays an important role in the VBNC conversion of Listeria monocytogenes. Because this adaptation is common, it may promote the establishment of reservoirs of subclinical but elusive pathogens, representing a significant public health hazard.
Because Cardiobacterium transforms itself to a normal state, the relative culture with glycolytic cells can be a suitable solution to establish its full cycle infections leading the research team in the price of factors responsible for the dormant state and condition favoring turning it into an active pathogen and above all permits development tools exclusively detecting this bacterium for optimum safetyoplevelse Er du anonym. This insight into bacterial dormancy could lead to better strategies for eliminating pathogens and improving efforts to ensure food safety and protect public health. Ultimately, these findings can help construct a broader defense against the forces of darkness that lurk in this world — in our food supply.
