Lecture 26 Flashcards
What is a biofilm?
A biofilm is a group of microorganisms where cells stick to each other and a surface, frequently embedded in a self-produced matrix of extracellular polymeric substances (EPS).
What is EPS in biofilm formation?
EPS (extracellular polymeric substance) is also known as slime and is composed of extracellular DNA, proteins, and polysaccharides in various configurations.
What are planktonic cells?
Planktonic cells are single cells that float or swim in a liquid medium. They have lower resistance to detergents and antibiotics compared to biofilm cells.
What is quorum sensing?
Quorum sensing is cell-to-cell communication that controls gene expression, allowing microorganisms to survive in hostile environments by coordinating their behavior.
What are the stages of biofilm formation?
Initial Attachment: Free-floating microorganisms attach to a surface.
Irreversible Attachment: Microorganisms anchor more permanently using cell adhesion structures.
Maturation I: Other cells attach and begin building the matrix.
Maturation II: The matrix protects cells and facilitates communication among them.
Dispersion: Cells disperse from the biofilm to colonize new surfaces.
What infectious processes are biofilms implicated in?
Biofilms are involved in urinary tract infections, catheter infections, dental plaque, and ear infections.
Which microorganisms are typically involved in dental plaque formation?
Streptococcus mutans and Streptococcus sanguinis
What agents can be used to destroy biofilms?
Detergents: alexidine, chlorhexidine
Preservatives: cetrimide, bronopol
