Meet the 2024 Microbiology Society Translational Microbiology Prize Winner, Professor Catherine Rees

02 April 2024

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Each year, the Microbiology Society awards the Unilever Colworth Prize to an individual who has made a significant contribution to translational microbiology.

Ahead of the Unilever Colworth Prize Lecture, Kezia Taylor interviewed Professor Catherine Rees to learn more about her career and how it feels to win a Microbiology Society prize.

How would you summarize your work to a member of the public?

The translational aspect of my work has been developing new methods for detecting mycobacteria, such as the bacteria which cause tuberculosis (TB). Most disease-causing bacteria can be grown up and identified quickly. However mycobacteria can take up to 18 weeks to grow in the lab. To work around this, diagnostic tests for TB have always assessed whether a patient’s immune system has been exposed to TB, instead of directly detecting the disease-causing bacteria. The problem with these tests is that vaccinated individuals will also test positive for TB, and they also tell us nothing about what the bacteria are doing inside the patient. The basic purpose of this project has therefore been to develop a method to detect these mycobacteria without having to spend three months growing them in a lab. My other passion in life is bacteriophages – viruses that infect bacteria – and finding ways to utilize their specificity. The culmination of this work has been developing a new diagnostic test which uses phage to specifically detect mycobacteria in blood.

How is your work contributing to the global fight against TB?

This project has been running for 30 years and started off as a biological assay which uses a broad-spectrum phage to detect the presence of mycobacteria. Then PCR came along, and the diagnostic problem was solved for most bacteria, at which point people lost interest in phage-based diagnostics. However, mycobacteria are difficult to detect by PCR because they grow incredibly slowly and have this beautiful, thick, waxy cell wall which laughs in the face of the physical or chemical methods we normally use to break bacteria open. We therefore adapted our original commercial test kit and used the phage to break the mycobacterial cells open from the inside, releasing DNA for PCR. Having successfully developed this into a diagnostic test for Johne’s disease in cattle, we went on to use this trick to develop diagnostic tests for both bovine TB and human TB.

TB is what we call a spectrum disease. This means that a range of things can happen when you first get infected and disease progression can be very variable. In humans, there is a long, ‘latent’ period before an individual presents with clinical symptoms, during which time the disease may or may not progress. The most exciting part of our work was discovering that a phage-positive result, which indicates that TB is present in the circulating blood, is a sign of disease progression. This means that we can now detect TB infection during the latent period and start treating patients before they are present with clinical symptoms.

In what ways would you describe your work as being ‘translational’ and why is translational research so important to you?

To be honest, the translation part has been tiny. It took 30 years of fundamental science for us to understand phage-host interactions and the biochemistry of our system enough to be able to achieve this small aspect of translation in the end. The question is: is any science not translational? I have never seen a scientist asking questions without a purpose. All research generates foundational knowledge that we want to have an application at some point. It just varies how close you are to that end point of realizing: ‘I could use this’. You never know what is going to be useful, a bit like NASA and non-stick saucepans!

What are some of the biggest challenges that you faced moving into the industry sector from an academic background?

Working with industry requires a whole different mindset – that was the biggest learning curve. What you can do theoretically as a scientist and what makes a good business case are two very different things. Moving into industry, you start working in certainties, and scientists do not like certainties! Also, a lot of the work required for validation can feel repetitive and a bit dull because you are not actually moving your research forward. Coming from an academic background, you re-equilibrate your way of thinking. You need to start seeing things from the point of view of financiers, regulators, and policymakers, which was a whole new ball game. In the end, one of my biggest realizations was that the process of moving a scientific idea into a product is not my passion. For some people it is, and I do not want to denigrate that type of research, but I think it is important to recognize where your strengths lie and for me, that is on the innovation side.  

What challenges have you faced translating your research between animals and humans?

Our work started with humans, then we moved to animals and finally back to humans again. Weirdly, it was much easier to validate our diagnostic test for TB in humans than it was in cattle. One of the major challenges we came across was that it was illegal to test cattle for TB in the UK and when working with animals you can’t ask them for consent. Once we started the process of validating the bovine TB test for the market, we came across so many regulations: notifiable disease policies, home office licenses, the Animal Protection Act… Whereas if you go to a human TB clinic and ask for 5ml of blood, you are good to go! That was another learning curve because you would assume that starting with cattle would be easier.

What excites you most about the potential of phage-based diagnostics and what direction would you like to see this field heading in?

In addition to adding a new dimension to TB diagnostics, it is exciting that we have created a tool which allows researchers to ask questions in their fundamental studies that they could not before. Fundamental studies investigating where TB cells are during infection and what they are doing inside the host were difficult to do previously, because they required culturing. One of the first things we realized when we were developing the phage assays was that they could be used as a tool to interrogate what the bacterial cells were doing and improve our fundamental understanding of TB. For example, phage can sense the metabolic state of bacterial cells and will not infect dead cells, which could be useful for discovering new drug therapies.

Having recently stepped down from your position at PBD Biotech Ltd, what are you looking to do next?

One of my collaborators is continuing to conduct fundamental TB studies at the Royal Veterinary College and we are still following up on the human studies with the hospital in Leicester, so there is a lot in which we are interested. To be honest, I am getting to the point in my own career where I am beginning to wind down, so what I’m involved in at the moment is a lot of collaborating with other groups and setting up new programmes. My key objective right now is to assist in getting this technology out there so that other people can benefit from it. I have also been taking on some government advisory roles and using my knowledge in different ways, which has been interesting and only involves a slight shift in emphasis.   

How has being a member of the Microbiology Society supported you throughout your career?

Oh, endlessly. Going to Society meetings has been the background framework to my career. Networking with new people and learning new things is important in the innovation sphere – often the biggest surprises come from listening to a session at a conference or talking to someone who is doing something completely different to you. There is a synergy between these random conversations that you just can’t plan, and I think these casual meetings are something we are really missing post-COVID. Keeping in touch with people through conferences and accessing that personal level of science has been the best part of the Society, for me. I was on various organizing committees many years ago, helping to foster that network of people, and I think that having societies that support broad meetings is important for generating new ideas.