Biofilms
Bacteria seldom exist as free floating solitary cells. In most environments they live in association with surfaces as part of multi-species biofilms. From freshwater environments to marine systems to the human oral cavity, these communities exhibit properties that are distinct from free floating cells. As such, the amalgamation of different species within these communities can:
Enhance antimicrobial resistance.
Promote the breakdown and corrosion of surfaces.
Promote or hinder the integration of pathogenic bacteria or fungi.
Act as a reservoir for the spread of microorganisms to uncolonized areas.
How different species adhere, communicate, and grow as a unified community is critical to understanding how to control these communities.
C.E. Fernández, M.B. Aspiras, M.W. Dodds, C. González‐Cabezas, A.H. Rickard, The effect of inoculum source and fluid shear force on the development of in vitro oral multispecies biofilms, Journal of Applied Microbiology, Volume 122, Issue 3, 1 March 2017, Pages 796–808, https://doi.org/10.1111/jam.13376Our Focus
The focus of the Rickard research group is to elucidate the underlying mechanisms that promote multi-species biofilm development.
To achieve this, our research often strives to focus on natural multi-species biofilm communities and/or the interactions between the component species under environmentally germane conditions. Our work is important because real-world wild-type bacteria behave differently as compared to domesticated laboratory strains.
Recent studies indicate that inter-species interactions are essential for the ordered successional integration of bacteria into biofilms. This process is required for establishing juxtaposition between different species and may promote cooperation between species within a biofilm.
Using an array of physiological, ecological, molecular, and computational techniques in combination with biofilms developed in vivo and in vitro, it is our goal to understand factors and processes that contribute to the multi-species biofilm lifestyle and its behavior.
The behavior of the biofilm will dictate the potential of the biofilm community to promote health or be problematic and/or cause disease.
Rickard, Alexander & Hayashi, Michael & Redissi, Aneesa & Fenno, J. & Jakubovics, Nicholas. (2024). Bacterial Coaggregation: A Way Different Bacteria Come Together. Frontiers for Young Minds. 11. 10.3389/frym.2023.1212262. Interspecies interactions can be through two key mechanisms:
Coaggregation interactions between genetically distinct species
Chemical signaling within and between species
Both of these processes have been identified as occurring between bacteria in the natural environment and between bacteria in the human microbial microbiome.
Furthermore, evidence is emerging that synergy between coaggregation and signaling may occur. In these instances it is hypothesized that coaggregation brings species in close proximity and thus exposes bacteria to elevated concentrations of signal molecules. These signals can be metabolites or quorum sensing molecules.