Biofilms can cause various infections:
Burn infections
Wound infections
Respiratory infections
Example of albuterol inhaler contamination:
Contaminated production line resulted in inhalers with Pseudomonas cells.
Patients with chronic respiratory issues inhaled contaminated medication, leading to infection.
Cells attach to a surface.
Can involve structures like flagella, fimbriae, or glycocalyx.
Attachment is not strong; cells simply land on the surface.
Cells begin to attach tightly to each other.
Pili, fimbriae, or glycocalyx aid in sticking together.
Exopolysaccharide (EPS) production starts, crucial for biofilm development.
If washout occurs, biofilm formation is halted.
Increased EPS production occurs, leading to:
More cell attachment.
Cell division within the biofilm.
Expansion of the biofilm structure.
Continuation of maturation 1.
Further EPS production and cell accumulation.
Free-floating cells leave the biofilm.
Offspring of original cells disperse to establish new biofilms elsewhere.
Occasionally, chunks of biofilm break off and attach to new surfaces.
Researchers study microbes forming thick biomats, displaying multiple colors indicating different microbial layers.
Attempts to transfer biomats to other surfaces often disrupt growth.
Introduction of sterile surfaces can result in new biofilm formation upon immersion in microbial-rich environments.
Key structures contributing to biofilm formation:
Glycocalyx: Provides a protective layer for cells.
Pili and fimbriae: Assist in initial attachment and collective stability of cells.
Structures can vary by organism, serving either attachment or movement roles.
Flagella are essential for motility in bacteria.
Pili and flagella might look similar but serve different functions:
Pili: Attachment and adherence.
Flagella: Movement and propulsion.
Flagellum structure includes:
M ring: motor functionality, providing rotation.
S ring: structural support.
P ring: support within the cell wall.
Hook: connects filament to the motor.
Filament: extends to propel the cell.
Entire flagellar structure rotates, not just the filament, enhancing cell propulsion.
Torque generated allows efficient movement.
Energy input:
Requires protons to rotate the motor (3 protons equal one full rotation).
Proton channels (Mode A and Mode B) facilitate energy transfer for motion through the flagellar motor.
Proton influx promotes rotation and thus cell movement, effectively key to bacterial survival.
Gram-positive cells:
Present with P ring made of peptidoglycan layer.
Gram-negative cells:
Additional L ring for lipopolysaccharide structure.
Mechanical and functional similarities, but L ring adds an extra layer of durability.
Loss or damage to any part of the flagellar structure affects motility:
M ring failure = no movement.
S ring damage = structural compromise.
Energy investment in building and maintaining flagella highlights their functional importance.
Understanding biofilms and their formation is essential in microbiology and bacterial pathology.
Recognizing roles of various structures like flagella, pili, glycocalyx, and EPS is crucial in understanding microbial behavior and infection pathways.
Discussion and exploration of new topics, such as angella and movements related to flagella, to continue in the next session.