Microverse Microbe of the Year 2025 – Candida albicans, the hidden roommate

On the occasion of the International Microrganism Day, the Cluster of Excellence “Balance of the Microverse” has chosen the Microverse Microbe of the Year for 2025. The choice fell on Candida albicans, a fungus carried by up to 95 percent of all people. Normally, it is a harmless cohabitant of our mucosal surfaces. But when the body’s balance is disturbed, Candida albicans can reveal its other side.

From fellow inhabitant to pathogen

The world of fungi is vast: researchers estimate that there are three to five million different species. Only a fraction of these, approximately 150 to 400 species, can cause disease in humans. Infections arise in two ways – either through exogenous pathogens from the environment, such as molds, or through endogenous pathogens that already exist as part of the human microbiome. Candida albicans belongs to this latter group of endogenous pathogens.

The fungus usually lives harmlessly within us but can cause illness under certain circumstances. Mucosal infections with Candida albicans are widespread. Infants, elderly people, or patients with weakened immune systems, for example, may experience infections of the oral mucosa, while two-thirds of all women experience at least one vaginal Candida infection in their lifetime.

The situation becomes dangerous when the fungus enters the bloodstream of seriously ill patients. Such systemic infections can be life-threatening. Worldwide, around 1.5 million cases are reported every year, with a mortality rate of about 35 percent. Thus, an inconspicuous co-resident can become a medically significant pathogen.

Research in focus

At the Leibniz-HKI in Jena, Professor Bernhard Hube has been studying the mechanisms that enable Candida albicans to turn from benign to pathogenic for many years. Together with his team, he investigates how the fungus colonizes mucosal surfaces and which mechanisms can lead to infections.

“There are hardly any microorganisms that are so frequently associated with humans and at the same time can so often cause infections as Candida albicans. If we better understand how healthy people and their microbiome keep the fungus under control, we will also be able to prevent and combat infections more effectively in the future.”

More than just a germ

With the choice of the 2025 Microverse Microbe, the Cluster of Excellence “Balance of the Microverse” aims to show that Candida albicans is part of our everyday lives and at the same time a warning signal of the dangers that arise when the balance between humans and microorganisms is disturbed. Every new insight into this fungus helps to prevent infections, diagnose them more quickly, and treat them more effectively.