How Bacteria Detect Nearby Death and Gear Up for Combat

Researchers at the University of Basel have uncovered how bacteria sense environmental threats using a universal danger signal. When nearby cells are dying, bacteria detect fragments of their cell walls, called peptidoglycans, and proactively form protective biofilms. This discovery sheds light on bacterial communication and defense mechanisms, offering insights for combating infections.

Sensing Danger: The Role of Peptidoglycans

Bacteria face constant threats from immune cells, antibiotics, and bacteriophages—viruses that specifically target them. To survive, they’ve evolved strategies to anticipate and counteract danger. The research team, led by Prof. Knut Drescher at the Biozentrum, University of Basel, identified peptidoglycan fragments as a universal alarm signal released when bacteria are killed by phages or antibiotics.

“These fragments signal danger not just to the same species but also to different bacterial species,” Drescher explains. This broad recognition of peptidoglycans enables bacteria to detect threats in their environment early.

Defensive Response: Building Biofilms

Upon sensing peptidoglycans, bacteria produce a signaling molecule, c-di-GMP, which triggers the formation of biofilms—complex, slimy structures that shield them from threats.

“In Vibrio cholerae, the cholera-causing pathogen, even brief exposure to cell wall fragments initiates biofilm formation,” notes Sanika Vaidya, the study’s first author. Within these biofilms, bacteria are better protected from phages, immune responses, and antibiotics.

Cross-Species Survival Mechanism

This behavior was observed not only in Vibrio cholerae but also in multi-drug-resistant pathogens like Pseudomonas aeruginosa, Acinetobacter baumannii, Staphylococcus aureus, and Enterococcus faecalis. The universal nature of this response underscores its evolutionary importance.

“Interestingly, human immune cells also recognize peptidoglycan fragments as infection signals,” Drescher points out, highlighting parallels between bacterial and human defense systems.

Implications for Medicine: Targeting Biofilms

Biofilms play a critical role in both natural ecosystems and persistent human infections. Understanding how bacteria sense danger and form biofilms opens new avenues for medical intervention.

The study raises intriguing questions: Do cell wall fragments activate other protective strategies? How can these findings be harnessed to prevent biofilm-related infections? Exploring these pathways could revolutionize how we combat biofilm-forming pathogens.

Read Original Article: Scitechdaily

Read More: Major Depression Breakthrough: Nearly 300 Previously Unknown Genes Discovered