Biofilms

Biofilms are structured communities of microorganisms that attach to surfaces and are embedded in a self-produced extracellular polymeric substance (EPS) matrix. They form on biotic and abiotic surfaces in natural, medical, industrial, and environmental settings and can include bacteria, yeasts, algae, and archaea, often as multispecies communities.

Biofilm development involves several stages. Free-floating (planktonic) cells initially make reversible contact with a surface, followed by irreversible adhesion. The community then matures into three-dimensional structures containing microcolonies and water channels that facilitate nutrient distribution and waste removal. In this mature state, cells exhibit metabolic and physiological diversity, leading to gradients of growth and activity within the biofilm. The EPS matrix, composed of polysaccharides, proteins, nucleic acids, and lipids, provides structural integrity, protection, and resilience against external stresses and antimicrobials.

Ecology and significance: Biofilms confer advantages to resident microbes, including enhanced resistance to desiccation, shear forces, and chemical antimicrobials. Resistance arises from limited antimicrobial penetration, slow-growing or dormant subpopulations, and cooperative interactions. Biofilms are associated with a range of persistent infections (such as on medical devices or chronic wounds) and dental plaque, as well as environmental and industrial problems like biofouling and biocorrosion.

Management and prevention: Detection and eradication are challenging and often require mechanical removal combined with chemical disinfectants or enzymatic treatments. Prevention focuses on reducing initial attachment and maturation through effective cleaning, surface modifications or coatings that deter adherence, optimized flow or cleaning regimes, and strategies that disrupt quorum sensing or EPS integrity.