Bacterial Survival During Desiccation

This research project will investigate the ability of bacteria to survive desiccation conditions. When bacterial cells experience a significant removal of water and become metabolically inactive, they may no longer be able to form colonies and therefore cannot be detected by conventional growth tests even though the bacteria are still alive. Once more favorable growth conditions are available, the bacteria can recover from their inactive state and begin to divide. This can be a critical concern in the food packaging industry for storage of dried foods such as spices, grains and other packaged foods. Surfaces in processing plants may not be safe if the bacterial contaminants cannot be readily detected. This also impacts the clinic, which relies on growth tests to detect the presence of many types of pathogens in biological samples. In all of these examples, bacteria may be present and alive but not readily detected due to their ability to enter an inactive state, which poses a serious challenge to maintaining health and safety standards. The experiments outlined in this proposal will evaluate the survival of bacteria that had been exposed to desiccation and then allowed to recover when returned to a more favorable aqueous environment. The recovery of a common E. coli strain from desiccation stress will be examined as an example of microbes important to the food industry and human health. We will measure changes in the amounts of major cellular components in response to drying and identify important properties of cells that support tolerance to desiccation conditions. Understanding the basis for desiccation tolerance will be critical to devising and implementing new strategies for detecting and eliminating contaminating microbes.