Our interview with Professor Sarah Lebeer

Sarah Lebeer is a Professor of Microbiology & Biotechnology at the University of Antwerp and is currently leading a team of researchers in exploring the field of the vaginal microbiota & women’s health. We caught up with her to find out more about her career and research… 


1. Can you tell us about your career path, and how you got to your current position as Professor of Microbiology & Biotechnology at the University of Antwerp? 

I did a masters, PhD and short post-doc in Bioscience Engineering at the KU Leuven (Belgium), but I had done a bachelor degree at University of Antwerp (Belgium). In 2011, I was approached by the University of Antwerp because they were looking for candidates for a research Professorship in microbiology (tenure track). The candidate also had the opportunity to start a whole new research lab and research line on applied microbiology and biotechnology. I did apply and was very happy to get the job as Assistant Professor. Currently I am a full Professor 8 years after my first appointment. I was lucky that I received a lot of freedom with the start-up of this new lab, which I could dedicate to beneficial bacteria and their applications.


2. What led to your interest in biosciences, microbiology and more specifically to your interest in pre- and pro-biotics? 

During my masters, I became inspired by my Professor, Jos Vanderleyden, who was mainly doing research on beneficial bacteria for plants, such as Rhizobium and Azospirillum. He was starting up a new research line on beneficial bacteria for the human gut and I was the third PhD student on that topic in his group.  With a background in gene technology, I was eager to apply molecular tools such as knock-out mutagenesis to better understand the function and important molecules of probiotics. I was intrigued by the fact that positive microbes also exist. The main thing I struggled with since the start of my profession is that the phenotypes of beneficial bacteria are generally much more subtle than pathogens, so they are more difficult to characterize. How a good microbe can make someone healthier is a more complex question than how a bad bug can make you sick.


3. You recently co-authored a paper that was published in the International Journal of Systematic and Evolutionary Biology about the taxonomical classification of the Lactobacillus genus– could you give us some brief background as to why it was necessary to divide this genus into 25 different genera? 

It was necessary to have better tools to describe taxa that share common phenotypes and functions. For example, the new genuine Lactobacillus genus (old Lactobacillus delbrueckii group) is made up of bacteria we can now describe as host-adapted, homofermentative, vancomycin-sensitive and lacking pyruvate formate lyase. They include the yogurt bacteria and the vaginal type strains such as L. crispatus, L. gasseri, L. jensenii and L. iners. This evolutionary link has become clearer thanks to the taxonomic changes, but has not yet been properly investigated. 


In addition, we can now also ask questions we could not ask before. For example: 

• Does the interaction of nomadic Lactiplantibacillus probiotics differ from the interaction of host-adapted Lactobacillus and Limosilactobacillus (former L. reuteri group) probiotics?

• What are possible core beneficial properties of the most commonly used probiotic genera such as Lactobacillus, Limonsilactobacillus, Lactiplantibacillus and Lacticaseibacillus?

• Can propionic acid formation by Lentilactobacillus (former L. buchneri group) organisms be used for food preservation?


It is my hope that the name changes will advance probiotic science. Not all probiotics are the same, and this is now better reflected with the new genera names. 


4. You are currently working on a new citizen science project at the University of Antwerp, called Isala, which explores the female microbiome. Could you explain more about this project and the importance of it? 

Isala is a super cool Citizen Science project we have started with funding of my ERC project Lacto-Be (www.isala.be). The project is named after Isala Van Diest (1842-1916), the very first female medical doctor in Belgium. She had to study in Switzerland because no women were admitted to Belgian universities at the time. But she persisted, and she made history. 

The project was launched in March 2020, during the COVID-19 pandemic, and we were afraid that we would not reach the 200 volunteers we aimed for. But in a short time period, more than 5000 women said they were willing to donate a vaginal swab and that they wanted to become joint ambassadors for women’s health. The scientific objective of Isala is to gain more in-depth knowledge on the role of lactobacilli in the vaginal microbiome and better link their presence to lifestyle and hygienic factors, contraceptive use, food habits, etc. And because it is a Citizen Science project, we also want to increase the awareness on the importance of the vaginal microbiome. 


5. What future research would you like to see in the field of women’s health, specifically relating to the vaginal microbiota? 

As already touched upon, I am really curious how food intake (such as fermented foods, fibres etc) impact on the vaginal microbiome. In addition, I think that probiotics have an underexplored potential to improve the vaginal microbiome, because the ecological role of lactobacilli is much clearer in this habitat than in the gut. 


6. You have been involved in many projects throughout your career, but are there any projects that you feel were the most instrumental within the development of your career? 

The first international project I got involved in was the genome sequencing project of the widely used gut probiotic Lacticaseibacillus rhamnosus GG (LGG), led by Prof. Willem de Vos and Soile Tynkynnen from Valio. Prof. Willem de Vos was very happy with the knock-out mutants we could construct to substantiate the role of the SpaCBA pili in the beneficial properties of LGG and he was a mentor for my later career.

A few years later, I had the chance to collaborate with Prof. Gregor Reid on the genome sequence and knock-out mutagenesis of the most widely used vaginal probiotic Lacticaseibacillus rhamnosus GR-1. He made me aware of the huge potential of vaginal lactobacilli as probiotics and introduced me in the International Scientific Association on Probiotics and Prebiotics (ISAPP). He also became a great mentor. 


7. What does a typical working day look like for you? And how have you had to adapt this during the COVID-19 pandemic and social distancing? 

I normally bring my three kids to school by bike - The school is just next to our lab. Normally I have a lot of face-to-face meetings with the team to discuss lab results, manuscripts and future planning. During the COVID-19 pandemic, we quickly managed to organise many things via Teams and Skype, but the lab was only fully closed for four weeks. Universities are essential sectors and did not fully close in Belgium. We also offered our microbial facilities to the national testing task force, but Belgium had enough facilities.


8. You have been a member of the Academic Board of the International Association on Probiotics & Prebiotics (ISAPP) for some time now in varying roles. What responsibilities do you have within your current role and what do you enjoy the most about being part of this Board? 

What I enjoy the most is the opportunity to have inspiring interactions with real experts of the probiotic field like Mary Ellen Sanders, Todd Klaenhammer, Gregor Reid, Bruno Pot, Dan Merenstein, Colin Hill, Karen Scott, Glen Gibson,  Seppo Salminen, Maria Marco, Bob Hutkins, Hania Szajewska... Thanks to ISAPP, I think I had the chance to meet almost all of my science heroes, also from outside the board, e.g. when they were invited as an expert speaker. Last year, I was the local host for the annual meeting in Antwerp. This year, the annual meeting was only virtual, but Karen Scott and I chaired a nice interactive discussion group on the role of the (gut) microbiome in chronic and infectious diseases, including COVID-19.

Currently, I am involved in panels formulating some new consensus definitions on fermented food and postbiotics. 


9. What inspires you most about working in research and where do you imagine this will take you in the future? 

I love to work with enthusiastic students and young scientists. And intellectually, I love to be continuously challenged. It is fascinating how knowledge is built: how you can design experiments to improve and fine-tune your knowledge. I am happy if an experimental result is not what we expected, because you can learn a lot of new things from unexpected results. Then I always tell the students that this is the reason why we do experiments, with an open eye to observe new things. Microbiome and probiotic science is a fascinating area to work in, with lots of things to be discovered.


10. If you could go back to when you were a student and give yourself one piece of advice what would it be?  

I would advise myself to study microbiology earlier. In addition, you don’t have to go and study abroad to have an international network and scientific career. I have three kids and research abroad has not been and will not be possible in the next few years. But there are other ways to broaden your network, such as joining the students and fellow association of ISAPP (isappscience.org/for-students/).