Expérimental et théorique
The colonization of surfaces by bacteria raises many societal issues related to antibiotic resistance and waste management. Our grasp on initial surface establishment, crucial to address colonization at its roots, is limited. In this early stage, bacteria number fluctuations – due to surface adhesion, division, or motility – are large, challenging current analysis tools and theories. These fluctuations can result in more tight or sparse aggregates, dramatically affecting long-term colonization dynamics. How do individual dynamics and intermittent adhesion determine these aggregate patterns and collective growth? To make progress, we will use a new analysis technique relying on number fluctuations called the ``Countoscope’’ [2]. The principle is like a game! We count the number N(t) of particles (bacteria, colloids or cells) in analysis boxes over time. The number of particles in a box fluctuates due to microscopic dynamics such as diffusion, adhesion, etc. Interpreting N(t) requires building new theories in this colonization context. These theories can then disentangle processes and quantify dynamics from the time-dependent statistics of N(t). Here we will, on the one hand, count the number of bacteria in various box sizes on experimental images. On the other hand, we will develop minimal models to interpret these counts. This internship will be in collaboration with Eleonora Secchi (Zurich), who investigates bacteria on surfaces in microfluidic channels.