InterPore2026

Hydrodynamic dispersion in flowing networks induces bacterial (mis)communication

21 May 2026, 12:50

15m

Oral Presentation (MS02) Environmental Porous Media: Water, Agriculture, and Remediation MS02

Speaker

Dr Yohan Davit (Institut de Mécanique des Fluides de Toulouse, UMR 5502 CNRS Institut National Polytechnique de Toulouse, 31400 Toulouse, France)

Description

Keywords: Hydrodynamic dispersion, Porous media, Quorum sensing, S. aureus, Transport Phenomena

Bacterial environments are inherently dynamic, with fluid flow constantly shaping their physicochemical landscape in non-trivial ways. Quorum sensing (QS) is a key mechanism by which bacteria communicate through the diffusion of QS molecules, termed autoinducers, to cope with these dynamic conditions. Quorum sensing mediates the attachment and detachment of bacteria, by regulating the production of surface adhesins and surfactants (1) or by controlling transitions between motile and sessile lifestyles (2). Physical diffusion of autoinducers couples local production to collective response (3), whereas advective transport can disrupt this coupling by washing the signals away and generating spatial heterogeneities (4) and regulating biomass accumulation in spatially structured environments (5).

Here we investigate the role of hydrodynamic dispersion in porous media on the QS communication footprint. While dispersion can increase the spreading of the communication zone, it can also suppress communication through dilution. We developed a microfluidic PDMS-glass porous system incorporating two inlets, one for a background flow and one for the introduction of synthetic autoinducer molecules, therefore mimicking the communication footprint in the wake of a colony. We combined this approach with fluorescence microscopy of a dual-labeled Staphylococcus aureus strain (mKate constitutive, GFP for QS activation). This strategy enables simultaneous visualization of the spatiotemporal dynamics of bacterial growth, viability, and QS activity. We also developed an advection-dispersion model to predict the spatial footprint of QS activation.

We observe QS response from single cells to early biofilm colonies, under different Péclet numbers tuned by the flow rate. By combining experiments with the transport model, we identify regimes in which hydrodynamic dispersion either promotes or suppresses QS and highlight key parameters that shape the QS footprint in porous media. These observations also provide insights into how autoinducer concentration gradients coupled with shear forces can create preferential colonization patterns and shape flow and transport in porous media.

These findings provide new insights into these couplings between flow, transport and quorum-sensing-controlled biological responses and may thus inform on the biofilm dynamics involved in environmental, health and bioengineering applications.

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