Pseudomonas. aeruginosa thrives within biofilms, where bacteria surround themselves with a self-made elastic matrix that protects them. Antibiotic treatments often fail because of antibiotic resistance; tolerance allows bacteria to survive antibiotic exposure without carrying the genetic changes that define resistance. A team led by Alexandre Persat at EPFL has now shown that confinement itself can make P. aeruginosa more tolerant to antibiotics. The study, published in the Proceedings of the National Academy of Sciences, shows that as bacteria grow in tight elastic materials, they are subjected to pressure that changes their physiology and helps them survive several types of antibiotic treatment. Physical confinement does more than compress bacteria; it also slows their growth. Cells in stiffer gels formed smaller clusters and became shorter. Slower growth likely explained part of the effect, especially for antibiotics whose activity depends on bacterial growth. But when the researchers released bacteria from the gels, the cells quickly resumed normal growth. However, even after release from confinement, bacteria remained less sensitive to antibiotics, suggesting that the effects of mechanical pressure can persist beyond confinement. @ https://phys.org/news/2026-06-physical-pressure-pathogenic-p-aeruginosa.html#google_vignette
