Scientists have discovered how bacteria that often cause stomach upset associated with seafood go dormant and then "wake up".
Vibrio parahaemolyticus is a marine bacterium that can cause gastroenteritis in humans when consuming raw or undercooked shellfish.
Some of these bacteria are able to enter a dormant state under harsh growth conditions such as low temperatures - and can remain dormant for long periods of time before reviving.
Scientists have identified a population of dormant cells that are better at waking up and discovered an enzyme involved in the awakening process.
Most of these bacteria die when encountering harsh growth conditions, but subpopulations of bacteria capable of remaining dormant for long periods of time were identified. This population has a better ability to recover when conditions improve. Tests have shown that when these dormant bacteria come to life, they are also virulent and capable of causing illness.
These findings may have implications for seafood safety, as dormant cells cannot be detected using conventional microbial screening tests and may underestimate the true bacterial load.
When they go dormant, these bacteria change shape, reduce respiratory activity, and they don't grow like healthy bacteria on the agar plates used in standard laboratory tests, so they are harder to detect. Using a range of tools, we were able to find dormant bacteria in seafood samples and laboratory cultures and look at their genetic content for clues about how they survive over the long term. It's important to note that thorough cooking will kill bacteria in seafood. Our results may also help us predict the conditions required for the resurrection of dormant bacteria.
Working with the seafood industry, a team has discovered a lactate dehydrogenase enzyme that breaks down lactate into pyruvate, a key component of multiple metabolic pathways.
The findings indicate that lactate dehydrogenase is essential for both maintaining bacterial dormancy and reviving active forms.
