In nature microorganisms often like to stay as biofilms.

What are biofilms?

Biofilms are complex aggregation of microorganisms attaching a surface. They are structurally heterogeneous, complex and characterized by the production of extracellular polymeric substances known as EPS.

How do they form?

Biofilm forms when bacteria adhere to surfaces in aqueous environments and begin to excrete a slimy substance that can help anchor the cell to surrounding surfaces. They can be formed by a single bacterial species, but mostly consists of many species of bacteria along with other form of living and non-living materials.

Single-celled or free living forms of cells are called as planktonic cells. Biofilms begins with the attachment of free-floating microorganisms to a surface. These first adhere to the surface initially through weak bonding by means of surface appendages such as flagella, pili or other cell adhesins. The cells further provide sites to build the matrix that holds these cellular communities together. These further facilitates attachment of other microbial communities. Once colonization has begun, the biofilm grows through a combination of cell division and finally develop in mushroom shaped structures. The matured community of cells then releases the planktonic form of cells.

Is there a talk between these communities?

There is interestingly a talk within the community termed as quorum sensing. The talk can be within the species or different species of microorganisms.

Where can I see them?

Biofilms are ubiquitous. The most common habitat is none other than the dental surface, in the form of dental plaque.

They can also be found in streams, rivers etc. on rocks and other surfaces exposed to water. Biofilms can be detrimental in water distribution systems and heat exchanger surfaces by causing clogging and corrosion.

On the tooth surface they may be responsible for tooth decay. The community of microbial cells have found to be involved in a wide variety of microbial infections in the body. Urinary tract infections (UTI), middle ear infection, contact lenses and catheter associated infections are few of the infections biofilms cause. They are resistant to most of the antimicrobial agents and thus pose serious threat from medical points of view.

These microbial communities are not always detrimental; they can also be beneficial as in sewage treatment plants, waste water treatment and bioremediation purposes. Biofilms can help eliminate oil spills from contaminated oceans or marine systems.

Biofilm is one of the favorite topics now a days and interesting work on its formation and disruption is going on.

This is just a prelude; further articles will provide insight on these complex microbial communities.