CLIP 1: BIOFILM GROWTH STAGES AND DISPERSAL. THIS SHOWS PLANKTONIC AND FRAGMENTING TYPES AND DIFFERENTIATES BETWEEN THE TWO PROCESSES AT THE END
YouTube – Clip_One_Rough_Cut.mp4
Seconds: 00-12: (focus on spinal prosthetic)
Narration 1: To illustrate the stages of bacterial biofilm growth, well show a patient with a prosthetic joint in their lumbar spine. The life cycle starts when bacteria enter the blood stream from any number of infection routes and evade the immune system or antibiotics. (18 seconds)
Seconds: 13-19: (showing pseudomonas entering blood stream):
Narration 2: Formation begins with reversible attachment of planktonic bacteria to a surface. A layer composed of polysaccharides or glycoproteins adsorbs into the substrate, changing the physical properties of the surface. Created by the human host, this conditioning coat now on the prosthetic surface is composed of fibrinogen, intravascular proteins and immune cells. Irreversible attachment to these host proteins is a strong signal to the bacterium to begin biofilm formation and is the first committed step of biofilm growth. (34 seconds)
Seconds: 20-26: (bacteria find tissue to land on and then attach themselves):
Narration 3: If the hosts immune system or antibiotics do not clear the bacteria, they anchor themselves more permanently using cell adhesion structures such as pili and receptors called epitopes. This encourages new species of bacteria to attach to newly arriving cells providing diverse adhesion sites and build the matrix that holds the biofilm together. The biofilm are now encased in a protective matrix and become more resistant to host immunity. (29 seconds)
Seconds 27-38: (bacteria creates a biofilm community)
Narration 4: Some species are not able to attach to a surface and anchor themselves to the matrix or directly to earlier colonists. Cells are now able to communicate via quorum sensing and use small molecules to regulate gene expression within the bacterium that make up the biofilm. The community grows through both cell division and recruitment. The development of this complex, polymicrobial biofilm makes these communities increasingly antibiotic resistant and includes diverse species of bacterias, yeasts, minerals and host proteins. (37 seconds)
Seconds: 39- 49(split screen shows both types of dispersal: planktonic and fragmenting, zooming in on planktonic)
Narration 5: The biofilm continues to recruit excess neutrophils, pro-inflammatory cytokines and host-derived proteases, producing a plasma exudate, a continuous source of nutrients. Bacteria now exist in multiple forms and metabolic states. The biofilm itself is now its own phenotype and becomes nearly impossible to eradicate. At some future date, it may continue its life cycle by releasing entire fragments of the biofilm community and/or enabling planktonic bacteria to once again begin the infection process. (39 seconds)
Total length: 157 seconds 😮
NARRATION SCRIPT ONE-Randy’s Comments.doc
WOUND BIOFILM.jpg
