Inaugural lecture

Bacteria whirl around in the mouths of most people, forming dental plaques and sometimes causing nasty gum infections. Treponema denticola might be a dangerous pathogen, but not much is known about this bacterium. It was up to Ariane Briegel and her research group to change that.

The challenge is considerable, but so is the satisfaction when it succeeds: creating complex sugar molecules that play a role in biology.

Last Friday the global Antibiotics Awareness Week begun: an entire week dedicated to antibiotic use. Antibiotics researchers from the LACDR therefore set out to tell primary school pupils about their research. Through role-playing, pupils were drawn into the world of antibiotics: 'Can the teacher not…

For the first time, it was shown in living cells how the bacterium E. coli regulates genes that help it survive in a new environment. Biochemist Fatema Zahra Rashid managed to do this using a technique she fine-tuned. Her research into changes in 3-dimensional chromosome structure offers clues for ways…

When a bacterium becomes more resistant to one antibiotic, it sometimes becomes more sensitive to another. To better understand this interaction, researchers from the Leiden Institute of Biology (IBL) and the Leiden Academic Center for Drug Research (LACDR) under supervision of Daniel Rozen and Coen…

A patent for what may be a potent, new antibiotic. And: a clear overview of promising approaches to overcome a crucial resistance tactic employed by bacteria. In the span of one week, two researchers from Leiden are receiving their PhDs, each of them on an important step in the battle against bacteria…

Leiden PhD candidate Jo-Anne Verschoor discovered that nearly twenty percent of the bacterial strains she studied could degrade plastic, though they needed some encouragement to do so. ‘Bacteria are just like people,’ says Verschoor. Her research was published in the journal Communications Biology,…

Soil that is too wet, or too dry. Or with a lot or few nutrients. Due to climate change, the differences are becoming bigger, and plants must increasingly be able to adapt to survive. How do you make plants more stress-resistant? For this purpose, researchers from Leiden, along with other universities,…

Bacteria temporarily live without their cell wall if dangerous viruses are near. A remarkable feature, as the cell wall is a sturdy barrier against threats. Still, the discovery has a logical explanation ánd might be of a consequence for fighting pathogenic bacteria, according to Véronique Ongenae,…

Researchers in Leiden have, for the first time, observed how a specialised enzyme helps bacteria stay alinve when oxygen levels are low, and how that process can be blocked. The discovery opens up new possibilities for targeted antibiotics.

More than 1.3 million people worldwide die of tuberculosis (TB) each year, making research on its prevention and control essential. Researchers from various disciplines in Leiden are studying TB. A symposium on 24 March will highlight different activities in the hope of boosting nationwide collabora…

Microscopic swimmers such as bacteria do not always swim alone. There are advantages to exchanging information and cooperating. Stefania Ketzetzi and colleagues now show in Nature Communications that human-made microswimmers, too, can cooperate.

A bacterium hiding from the immune system and picking up bits of DNA from its environment. The result: gaining new traits, such as better protection against antibiotics. Fortunately, we have not found such a damning scenario yet. However, PhD student Renée Kapteijn did find the first clues, which…

‘What I find most alluring about soil life is that you can steer it,’ researcher Martijn Bezemer of the Institute Biology Leiden (IBL) reveals. ‘You can ask: What do you want? And then I can transform the soil into something you need. At least, that is what we thought.’

Research to experiment with bacteria that grow like plants has been granted the NWO XS grant. These bacteria use light and carbon dioxide to grow, and will be designed especially for use in the biotechnological field. Tijn Delzenne and his supervisor Dennis Claessen can spend 50.000 euros on the exp…

Some bacteria, it turns out, have proteins much like ours that organise the DNA in their cells. They just do it a bit differently. This is revealed by new research from biochemists at the Leiden Institute of Chemistry and the Max Planck Institute for Biology. The discovery helps us better understand…

Fungi germinating in the lungs of patients. Doesn’t sound too nice, does it? Luckily, humans can deal with this normally, and we are able to clear the infection before anything comes to harm. However, in people with health issues, Aspergillosis can cause a lot of damage, especially if the fungus becomes…

Current antibiotics only address very few target proteins in bacteria to kill them. Researchers know that there are more possible target proteins to tackle the bacteria. The question is: which ones. Thanks to the NWO Vidi Grant, Assistant Professor Molecular Physiology Stephan Hacker and his team can…

From 22 to 24 October, researchers of the MARBLES-project informed museum visitors about microbes: bacteria and fungi that live all around us. The event was organised around the Micro-day of Leiden, which is this year’s EU City of Science.

Whether a microbe is beneficial or harmful to a plant can now be predicted with high accuracy thanks to bacLIFE. This bioinformatic tool with an intuitive interface makes it much easier to unlock the secrets of bacterial genomes. A group of Leiden biologists presented it in Nature Communications.

During an evacuation, employees and students of Humanities gather at the following assembly points:

Transferring poo from healthy donors to the intestines of chronically ill people has beneficial effects on these recipients’ gut bacteria, also in the longer term. This is the conclusion of research by the Leiden University Medical Center (LUMC) and the Netherlands Donor Feces Bank (NDFB).

Collaborating and learning from other fields – that is what bioinformatician Hannah Augustijn enjoys most about doing research. During her PhD at Leiden University, she developed new ways to search within bacteria for the antibiotics of the future.

Two research groups involving Leiden University have been awarded a major European grant, the ERC Synergy Grant. This for research on the development of membranes that can clean water and purify medical drugs and research on the biological clock in certain bacteria.

Two consortia led by Leiden researchers have been awarded over one million euros by the Dutch Research Council and the Ministry of Health, Welfare and Sport to find solutions to antimicrobial resistance.

Alumni event

A microscope with incredible sharpness that leaves samples unharmed – Guido Stam helped develop one. During his PhD research, he combined light and electrons to study biological samples. ‘We can now measure things that simply weren’t possible before.’

Our aim with the Humanities Campus is to create a sustainable and attractive campus with ample green spaces and opportunities for interaction, complemented by modern and future-proof facilities. The campus is being developed in stages. On this page, you can find information about the planning, latest…

The university strives to create a pleasant working environment for everyone. From terms of employment to health and development: here you will find the right information and support.

On 27 May 2025, the Executive Board decided to establish a Committee on Human Rights / Conflict Zones.

‘Working in Leiden is a dream come true.’ Ákos Kovács studied in his birth country Hungary and worked in Germany, Denmark and Groningen. As professor of Microbiome Ecology at IBL, he immediately started working together with his new colleagues to make discoveries about the versatile bacterial species…

Infecting each other with viruses and bacteria while protecting yourself with medicines and vaccinations. Sounds like a fun evening, right? Master students Life Science & Technology Rafael Jezior and Dennis de Beeld certainly think so. Together, they developed ImmunoWars: an exciting card game based…

Phage therapy is a novel yet unmatured therapeutic approach in the face of the crisis of antimicrobial resistance (AMR). Dr. Tingjie Guo received a grant from the Elise Mathilde Fund and the LUF to develop innovative phage-antibiotic combination treatment strategy for combating AMR.

Multidrug-resistant pathogens and worldwide pandemics are increasing, making infectious diseases more prevalent. To develop new treatments, deeper knowledge of the interaction between bacteria and human cells is required. Ariane Briegel recently became a Medical Delta professor and studies such path…

From 2026-2027, the Faculty of Humanities will add a new core curriculum course to its education: Humanities in a Digital World. The new course will prepare all students for their role as humanities specialists in the digital society. The course has been developed by experts from different study programmes…

Bacteria carry countless hidden treasures in their DNA: fragments that could hold the key to new medicines. But how do you pick out the most promising ones from millions of options? ‘Look at the switches that turn genes on and off,’ says molecular biologist Gilles van Wezel.

Research

PhD defence

PhD defence

Identifying novel antibiotic compounds to tackle antibiotic-resistant bacteria. Researchers from Leiden University and VU Amsterdam will unite through a project now funded by NWO’s Open Technology Programme (OTP), which awarded the collaboration nearly one million euros.

“Is it possible to restore antibiotic sensitivity in resistant bacteria?” Dr. Tingjie Guo wondered. “Watch me and learn”, phage responded. Dr. Tingjie Guo received an open competition XS domain ENW grant from the Dutch Research Council (NWO) to investigate the evolutionary trade-off of antimicrobial…