Bacteria responsible for seafood related stomach disturbs can go torpid and “wake up”

Overview

• Post By : Kumar Jeetendra


• Source: University of Exeter


• Date: 20 Jan,2021

Vibrio parahaemolyticus is a marine bacterium that can lead to gastroenteritis in humans when eaten in raw or undercooked shellfish such as oysters and mussels.

Some of these bacteria have the ability to turn dormant in poor growth conditions such as cold temperatures – and can stay in that state of hibernation for long periods before resuscitating.

University of Exeter scientists have identified a population of these dormant cells which are better at waking up, and have discovered an enzyme involved in that waking up process.

“Most of these bacteria die when they experience poor growth conditions, but we identified sub-populations of bacteria that have the ability to stay dormant for extended periods of time,” said lead author Dr Sariqa Wagley, of the University of Exeter.

“We found that this population has a better ability to revive when conditions improve.

“Our tests show that when these dormant bacteria are revived they are equally virulent and able to cause disease.”

The findings may have implications for seafood safety, as dormant cells are not detectable using routine microbiological screening tests and the true bacterial load (amount of bacteria) could be underestimated.

When they go dormant, these bacteria change shape, reduce respiration activities and they don’t grow like healthy bacteria on agar plates used in standard laboratory tests, so they are much 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 to look for clues in how they might survive for long periods. It is important to note that thorough cooking kills bacteria in seafood. Our results may also help us predict the conditions that dormant bacteria need in order to revive.”

Dr Sariqa Wagley, Study Lead Author, University of Exeter

The findings indicate that lactate dehydrogenase is essential for maintaining bacterial dormancy and resuscitation back to an active form.

Vibrio parahaemolyticus usually grows in warm and tropical marine environments, although Dr Wagley explained that because of rising sea temperatures in recent years it is now prevalent in UK waters during the summer months.

During the winter, it’s not detected in the marine environment around the UK and it’s thought to die due to the cold winter temperatures.

This analysis could explain how Vibrio parahaemolyticus is able remerge in the environment during the summer.

The study was partially funded by the Biotechnology and Biological Sciences Research Council (BBSRC), with additional funding and support from Lyons Seafoods.

The paper, published in the journal PLOS Pathogens, is entitled:”Bacterial dormancy: a subpopulation of workable but non-culturable cells demonstrates better fitness for revival.”