Biophysical Society Thematic Meeting | Ascona 2026

Mechanobiology of Infection

Poster Abstracts

3-POS Board 3 MECHANICAL REGULATION OF COLLECTIVE BEHAVIOR IN CONFINED NEISSERIA MENINGITIDIS POPULATIONS Merisa Avdovic 1 ; Sylvie Goussard 2 ; Morgan Delarue 3 ; Guillaume Dumenil 2 ; Daria Bonazzi 1 ; 1 CNRS, Institut Jacques Monod, Paris, France 2 Institut Pasteur, Paris, France 3 LAAS-CNRS, Université de Toulouse, Toulouse, France During meningococcal infection, Neisseria meningitidis (Nm) proliferates within blood vessels, where spatial constraints impose mechanical conditions distinct from standard culture. The extent to which such confinement leads to growth-induced pressure and how this shapes bacterial collective behavior remains unclear. Growth-induced pressure generated by Nm under confinement is quantified using a custom nanofluidic device with continuous nutrient perfusion. Pressure is measured through two complementary approaches: deformation of polydimethylsiloxane (PDMS) chamber walls monitored by phase-contrast microscopy and co encapsulation of hydrogel beads with defined mechanical properties acting as local force sensors. Proliferation under confinement leads to measurable compressive forces, yet with magnitudes lower than those reported for other bacterial species — suggesting that Nm has evolved to limit mechanical stress, a likely requirement for a pathogen that must preserve the integrity of the vessels it colonizes. The contribution of surface structures to this mechanical behavior is assessed using mutants defective in capsule production (siaD) and type IV pili dynamics. These mutants affect cell–cell interactions and packing, pushing the population toward jammed, solid like states that the wild-type actively avoids. These results reveal that specific surface structures govern the collective mechanical behavior of confined Nm populations, establishing a quantitative framework to study how confinement shapes Nm growth and organization in host like environments.

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