Biofilm

BiofilmLe Tran Quoc ThangPham Huynh Khanh Nam

OutlineDefinitionCharacteristicsFormationExamples

Definition of Biofilm:

A biofilm is a group of microbial cells that stick together after they have formed a matrix called the extracellular polymeric substance (EPS) on the surface of a material. EPSThe EPS is produced by these same microbes. These microbial cells are latched onto a surface made of various materials.The EPS is made up of DNA that is outside of the cells, also EPS is made of proteins, and long chains of sugar (polysaccharides)

Where and How is a Biofilm formed:

Biofilms can form on any substance, in any environment, such as hospital or in natureBiofilms are formed when microbial cells detect a specific or non-specific site that is suitable for attachment, or when there are signs of nutrient on a surfaceWhat characteristics are inside a biofilm structureWhen a group of cells become biofilm, their individual behavior changes, where bacteria genes are exchanged with one anotherWithin a biofilm, the micro-organisms can find ways to adapt to the external environmentEPS are also known as slime, they are made of biopolymers

The process of forming a Biofilm/Attachment:

Biofilm is first formed when the microorganism that floats around attaches to the surface.They first adhere to the surface by the van der waal forceIf they dont come off immediately, then attachment to the surface can be enhanced by cell adhesion such as aspili

The process of forming a Biofilm/Attachment:

Bacteria that are hydrophobic will be more attached to the EPS matrixSome bacteria species cannot form biofilm on their own, but must anchor themselves on colonies that exist before it.

What happens after a cell has been attached to the surfaceCells can communicate via quorum sensing within the biofilmMotile bacteria (moving ones) have a higher chance of successfully forming a biofilmWhen a colony has been settled, it grows by cell division and attraction of outside bacteria to the colony

What are the things that make up biofilm:

Apart from the materials that make up the biofilm, there can be other substances from outside environment such as minerals, soil particles, or blood parts.At the final stage, the biofilm can change its shape

What advantage does forming a biofilm has for bacteria:

The formation of a biofilm creates the condition that makes the bacteria in it antibiotic resistantThis is because of cell-cell interaction also known as quorum sensing

There are a few steps to a biofilm formationInitial attachment:Irreversible attachment:Maturation I:Maturation II:Dispersion

Final steps of Biofilm formation:

Dispersion is the process that makes the biofilm spread its progeny to a new colony. This is caused by an enzyme that degrades the biofilm and makes it ready to be detachedBiofilms are usually found when a solid comes into contact with a liquid solution

What is the EPS matrix:

The EPS consists of polysaccharides, proteins and nucleic acid.The matrix will enclose the cells within it, and within this structure, communication may be carried out by biochemical signal or gene swapping.The matrix encloses the extracellular enzyme and creates an environment for external digestion for cells

Difference between free bacteria and Bacteria in a biofilm

Bacteria in a Biofilm usually are different from free bacteria, because the environment of a biofilm allows the bacteria to interact with each other, making it resistant to antiseptic or antibioticsSometimes, the antibiotic resistant can be to a thousand foldsBiofilm is related to many microbial infections in the body, such as urinary tract infection, middle ear infection, dental plaque, contact lense

Examples of Biofilms

Eg, dental plaque is present on the surface of our teeth and consists of fungi and bacteria cells, the metabolic activity of the bacteria may cause tooth diseaseMost of the times, the acidity level in the mouth will be quite high, which would otherwise kill the bacteria or degenerates the DNA

Examples of Biofilms

However, some bacteria can go through transformation to repair its DNA, eg S.mutansEg of biofilm is S. pneumonia, which causes lung disease, these bacteria will form biofilm to adapt to the immune system of the host cells

How cells in Biofilm defend themselves

The host cells, leukocytes, can damage the DNA of the bacteriaS pneumonia can take up the DNA from cells close by to repair the DNA

Referenceswww.colgateprofessional.com/patient-education/articles/what-is-biofilmwww.biofilm.montana.edu/biofilm-basics-section-1.htmlscience.howstuffworks.com/life/cellular-microscopic/biofilm.htm