Meet the 2022 Fleming Prize Winner, Dr. Christopher Stewart

06 April 2022

Christopher Stewart Fleming Prize 2022 credit Christopher Stewart_ccexpress.jpeg

Each year, the Microbiology Society awards the Fleming Prize to an individual who has made a distinct contribution to microbiology early in their career.
Ahead of the Fleming Prize Lecture, Ruth Maganga, a member of our ECM forum, interviewed Dr. Christopher Stewart to learn more about his career and how it feels to win a Microbiology Society prize.

What drew you to a career in science, particularly in microbial ecology?

I am always jealous of the people who respond to questions like this by recounting an early childhood memory that set them on a very deliberate career path. However, relative to other subjects, I excelled in science subjects in my junior years and chose to study biology, chemistry, and Information technology for A levels. Not knowing what else to do once I left school, I decided to go to university to study Biotechnology, which I felt best encompassed my A level subjects. I wouldn’t consider myself especially studious, and it was not until the final year project, where I used micro- and molecular biology to study the microbial ecology of a lake sediment core, that I got a true taste for being a researcher. Leaving University, I did not really know what doing a PhD was and certainly had not planned to pursue a career in research. I had accepted a job in call centre to save up enough money to travel, when out of the blue I got an email from the supervisor of my undergraduate project, Prof Steve Cummings, explaining he had funding to explore the role of the gut microbiome in preterm infant health and disease and that I should consider applying.  I nearly did not apply, but I am glad every day that I did.

What findings in your career are you most proud of?

The first thing that springs to mind is our recent work exploring human milk oligosaccharides (HMO), which are abundant sugars in breastmilk, and the gut microbiome in preterm infants. This work was a testament to team-science and pulled together many of the people I have been fortunate to work with throughout my career, providing access to human samples and expertise in medicine, biochemistry, and microbiome. In a nutshell, using a relatively large cohort of preterm infants, we found a single HMO, disialyllacto-N-tetraose, can modulate the infant gut microbiome and is associated with a significant reduction in disease risk. This supports and builds upon previous work, and I will talk more about this study in my lecture.

What do you think will be some of the biggest leaps in the next five or ten years in your field? 

Technology has really brought microbiome science to the fore, from microbial ecology to bacterial genomics. I believe microbiome science will continue to flourish over the next decade, and it is great to see the field is attracting researchers from other fields, such as immunology, chemistry, mathematics, computational biology, statistics, public health, and many more.  When I started my PhD, this widespread enthusiasm for microbiome ecology was not where it is today. Although it is very important to take steps towards understanding this area, we are at a point of shifting from identifying which microbes are present within a given ecosystem, to understanding what is governing their function and how they interact with one another; for instance, understanding how microbes interact with each other and their host. I am especially excited about the potential for human organoids, that is primary cell lines established from human tissue, and how this technology can be used to better understand microbial-host interaction and hopefully accelerate translation of research and make strides toward stratified or personalised medicine

What message about your research would like to convey to an average person? 

Good question. I am fortunate to work on an area that really does capture public interest. This comes with downsides – many of my friends have children and think I can tell from a photo of a soiled nappy/diaper how healthy their child is (disclaimer: I cannot!).  Microbiome research seems to reinforce much of what we already knew, but places microbes at the center. As an example is that breast milk, the dietary source that provides the baby with optimal nutrition, is one of the main drivers of early life gut microbiome. Here, particular bioactive components of breast milk can influence the microbiome of an infant to promote ‘probiotic’, or potentially beneficial, bacteria.  Work is on-going to better understand the importance of early life diet-microbe-host interaction on short- and long-term outcomes, with the potential to give rise to new supplements and therapeutics.

What are the biggest challenges you have faced in your career and how did you overcome them?

I did not attend especially good schools growing up, and while I performed well relative to my peers, I still lacked the grades to get into top-tier Universities. By the time I completed my undergraduate and PhD at a post-92 University, I was keen to continue research, but found it hard to be considered at research-intensive Russel Group Universities in the UK.  I remember a particular conversation with one such University where I was told without a Cell, Nature, or Science paper I was unlikely to be considered for a tenure-track position. That was a real blow, and I am pleased that in the 7 years since I had that conversation things have moved on a lot, and most institutions have now signed up to DORA. Taking a positive from this conversation, it provided the catalyst for me moving to Houston Texas as a postdoc in Dr Joe Petrosinos lab. I was fortunate that my relocation expenses were covered; otherwise I would not have been able to move. Leaving my (now) fiancée and family was the hardest thing I have ever done, but I really did enjoy my time there and I learned so much. And there is a happy ending - my partner and I will get married shortly after I give the Fleming Prize Lecture!

Your research focuses largely on preterm babies in high-income countries; would you expect things to differ in low-income countries?

It is an incredibly important point and one I am very aware of. The disease for which my work is primarily focused, necrotising enterocolitis (NEC), is the leading cause of death in preterm infants in high-income settings but is much less common in low-income settings. This reflects that survival of extremely preterm infants is lower in low-income countries; as a result there will be less NEC. Research in this setting is important, but having adequate access to medical equipment and medication is far more important. On the research front, findings from high-income countries cannot simply be extrapolated to low-income settings because their environment and their access to medication are different, and of that will play a major role in governing how the microbiome develops. To this end, I am fortunate to be involved in an MRC-funded study to run a pilot trial of enteral probiotic administration in preterm infants admitted to a neonatal unit in Nigeria. This work is led by Oluwatoyin Tongo at the University of Ibadan in Nigeria and will hopefully spur more intensive research in populations that need it most.


Image: Dr. Christopher Stewart.