KNVM

The winner of the 2025 KNVM Microphotograph competition is: 

​​​​​​​"Hiding in the crevices: Staphylococcus aureus biofilm on titanium" by Lydia Speijker (MUMC+)

Shortlist of selected images in 2025: 

A | Hiding in the crevices: Staphylococcus aureus biofilm on titanium
Lydia Speijker - MUMC+

This scanning electron microscopy image shows Staphylococcus aureus biofilm formation after 24 hours of growth on a corundum-coated titanium surface. Tianium is often used in hip implants. The rough surface usually facilitates osteoblast settling, however the structure of the coating provides deep crevices where bacteria can also anchor and multiply. These sheltered niches contribute to the persistence of biofilms in prosthetic joint infections.

B | Strongyloides stercoralis in broncho-alveolaire lavage sample
Kara Osbak - Maasstadziekenhuis

An immunocompromised patient with respiratory insufficiency and sepsis underwent diagnostic bronchoalveolar lavage. Microscopy revealed numerous viable Strongyloides stercoralis worms, indicating Strongyloides stercoralis hyperinfection syndrome, a potentially lethal condition. The patient was treated with ivermectin and survived.

C | Life in a pond
Rob Mesman - Radboud University

Collage of dark-field microscopy images of various micro-algae found in a sample from a nearby pond.

D | The beauty of fungi
Xuewei Wang - Westerdijk Fungal Biodiversity Institute

Estimates suggest that around 15 million fungal species exist worldwide, yet only a fraction of these have been formally identified and named. This new Acropilus species, isolated from soil in France, exhibits ascomata with distinctive red-colored hairs, as shown in the picture. Documenting biodiversity like this is essential for deepening our understanding of biological processes in nature.

E | Ophiocordyceps unilateralis infection in a Camponotus ant
Emmeline van Roosmalen - Utrecht University

For my PhD research, I study how the fungus Ophiocordyceps unilateralis manipulates the behavior of its host ant. Each year, I travel to Florida to collect samples of both the ants and the fungus, which is where I captured this image. It is an ant infected by Ophiocordyceps as it undergoes the fungus’s life cycle. While the ant was still alive, the fungus altered its behavior, compelling it to climb vegetation and eventually bite onto a twig and hug it, called “the death grip.” After taking the ant’s life, the fungus consumed its internal tissues to fuel a stalk and fruiting body, which then emerged from the ant’s neck.