Biofilm facts for kids

A biofilm is any group of microorganisms which stick to cell surfaces.

These sticky cells create a slimy layer outside the cells of the body. The cells in the biofilm produce extracellular polysaccharides, proteins, lipids and DNA. Because they have three-dimensional structure they are a community lifestyle for microorganisms. They have been metaphorically described as "cities for microbes".

The biofilm bacteria can share nutrients and are sheltered from harmful factors in their local environment, such as desiccation, antibiotics, and the host's immune system. The film of bacteria which live on your teeth are an example. Biofilms also form on inorganic objects like stones in water.

Images for kids

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  Staphylococcus aureus biofilm on an indwelling catheter

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  Mature biofilm structure  Biofilm is characterised by heterogenous environment and the presence of a variety of subpopulations. A biofilm structure is composed of metabolically active (both resistant and tolerant) and non-active cells (viable but not culturable cells and persisters) as well as polymer matrix consisting of polysaccharide, extracellular DNA and proteins. Biofilm growth is associated with an escalated level of mutations and horizontal gene transfer which is promoted in due to the packed and dense structure. Bacteria in biofilms communicate by quorum sensing, which activates genes participating in virulence factors production.
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  Five stages of biofilm development  (1) Initial attachment, (2) Irreversible attachment, (3) Maturation I, (4) Maturation II, and (5) Dispersion. Each stage of development in the diagram is paired with a photomicrograph of a developing P. aeruginosa biofilm. All photomicrographs are shown to the same scale.
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  Scanning electron micrograph of mixed-culture biofilm, demonstrating in detail a spatially heterogeneous arrangement of bacterial cells and extracellular polymeric substances.

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  Mats of bacterial biofilm color the hot springs in Yellowstone National Park. The longest raised mat area is about half a meter long.

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  Thermophilic bacteria in the outflow of Mickey Hot Springs, Oregon, approximately 20 mm thick.

See also

In Spanish: Biopelícula para niños