HMN 2026: How New biofilm mechanism in Bacillus cereus could reveal vulnerabilities in food poisoning bacterium

Scientists from the Department of Microbiology at the University of Malaga, who are also members of the Institute of Subtropical and Mediterranean Horticulture “La Mayora” (IHSM), have discovered a previously unknown mechanism that allows the bacterium Bacillus cereus, which is responsible for food poisoning and human infections, to protect itself against antibiotics and adverse conditions. The study, published in Science Advances, reveals how these bacteria form biofilms, highly organized communities that act as a protective shield.

The bacteria aggregate in these biofilms and generate a matrix that isolates them from the environment, making them difficult to eliminate both in hospital settings and in the food industry. “This type of structure is behind many persistent infections and food contamination problems that are difficult to eliminate,” said Professor Diego Romero, one of the authors of the paper.

According to Romero, this discovery is critical not only because it expands knowledge of bacterial organization but also because it opens new opportunities to weaken the bacteria and improve their control in medicine and the food industry.

Protective scaffold

The research identifies, for the first time, the molecular system that enables the assembly of such a protective scaffold. Specifically, the scientists described a mechanism based on three key proteins—TasA, CalY and CapP—that coordinate the formation of filamentous structures on the exterior of the bacteria. This system, they said, works in a highly controlled way, ensuring the bacterial community is built in an organized and efficient manner.

One of the most important pieces of evidence is the role of the CapP protein, which acts as an “orchestra conductor,” controlling when and how these structures are assembled. “Without this control, the bacteria would not be able to form biofilms properly, which demonstrates its essential role in the survival of the microorganism,” they said.

Adaptability

In addition, the study reveals that Bacillus cereus has a remarkable capacity for adaptation. If this system fails, the bacterium activates alternative mechanisms—such as extracellular DNA production or changes in mobility—to maintain its protection. This “plasticity” helps explain why biofilms are so difficult to eradicate.

The study was carried out by the group BacBio at the University of Malaga and the IHSM, in collaboration with the University of Bordeaux and the CNRS. It stems from the doctoral thesis of researcher Ana Álvarez-Mena, who completed research stays in France during her training, specializing in structural analysis techniques at the atomic scale.

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