Exeter researcher secures over half a million pounds to tackle health conditions caused by dormant bacteria

Dr Sariqa Wagley

Over half a million pounds has been awarded by the Natural Environment Research Council (NERC) to tackle cholera and gastroenteric outbreaks caused by fatally occurring dormant bacteria.

Dormancy is a common occurrence in bacterial species that allows them temporarily halt growth and respiration in unfavourable conditions. Bacterial dormancy allows microbes to conserve their nutrients and withstand harsh environmental conditions that they would otherwise not survive in. When bacteria reawaken from dormancy, they can grow and reproduce resulting in infection.

Dr Sariqa Wagley, Research Fellow and Microbiologist at the University of Exeter, has received a five-year NERC Independent Research Fellowship worth £676,580 to investigate the activities and characteristics of the bacterial species Vibrio, which are responsible for gastroenteritis and cholera in humans and cause disease in shellfish leading to colossal damages to the aquaculture industry.

Dr Wagley’s project, ‘Now you see them, now you don’t – tracking hidden dormant bacteria in the environment’, will explore the geographical distribution of these dormant bacteria in the environment and the factors responsible for their awakening after a period of dormancy.

Vibrio species are naturally found in warm and tropical marine regions. However, due to rising sea temperatures they are now prevalent in the UK in the summer months. Most Vibrio bacteria will not survive cold temperatures and they are not detected in aquaculture and marine environments during the winter.  However, some Vibrio bacteria have been shown to enter a state of dormancy in the winter periods.

During dormancy, Vibrio species utilise nutrients sparingly, modify their shape and size to suit these adverse conditions, and when the conditions become favourable, they awaken once more to reproduce and cause seasonal infections.

Vibrio species include Vibrio parahaemolyticus which causes over five hundred thousand cases of gastroenteritis infections globally and Vibrio cholerae which results in up to four million cases of cholera infections yearly around the world.

Dr Wagley said: “The numbers of cases caused by Vibrio species in particular the cases of cholera infection just this year alone in Africa are staggering and have a huge impact on human lives. Dormant cells are not detectable by routine laboratory tests that we use to look for microbial contamination of samples because of the modifications these cells undergo during dormancy, so it’s been difficult to study them. It’s imperative to find ways to predict when these bacteria are going to come out of dormancy in the natural environment, so we can better prevent infections from arising in the first place.

“Recently, I used advanced flow cytometry techniques that are available at the University of Exeter to isolate dormant Vibrio cells from environmental samples and awaken them in a more detectable state. This ability to find dormant cells in their natural settings opens doors to understanding how they survive in the environmental and what governs them waking up when conditions become favourable.”

The NERC funding will enable Dr Wagley to build on her research into the conditions that foster reawakening of Vibrio bacteria after a period of dormancy in a bid to tackle it.

Dr Wagley added: “I’m really thrilled to receive this funding and over the next five years, I’ll be working to uncover the spread of these dormant cells in specific niches such as in the water column, shellfisheries, oyster guts and sediments to better understand them in their natural settings and how they are surviving in this prolonged state of dormancy.

“I’m keen to identify the mechanisms that aid resuscitation and how we may potentially stop it. The overall aim is to predict and prevent infections caused by Vibrio species before they harm human and other aquaculture species.”

Professor Peter Liss, Interim Executive Chair of NERC, said: “NERC Independent Research Fellowships support talented early career researchers to work independently and deliver cutting-edge environmental science. I’d like to offer my congratulations to all those who have been awarded a fellowship this year.

“Environmental research advances our understanding of the planet and is the key to tackling and adapting to critical challenges such as climate change. By investing in these fellowships, NERC is supporting innovation and sustainability in environmental science and developing leading researchers of the future.”