Final answer:
Pseudomonas aeruginosa forms biofilms by initially attaching to a surface, then using pili for permanent adhesion, growing through cell recruitment, and producing an EPS matrix for structural integrity and resistance, before dispersing to colonize new surfaces.
Step-by-step explanation:
Pseudomonas aeruginosa forms biofilms through a multi-stage process that allows it to securely attach to surfaces and protect itself from the immune system and antibiotic treatments. The initial attachment is mediated by weak van der Waals interactions, followed by irreversible attachment via pili that anchor the bacteria to the surface. In subsequent maturation stages, the biofilm grows through cell division and recruitment of other bacteria, held together by an extracellular matrix composed primarily of polysaccharides in the form of extrapolymeric substance (EPS). The EPS is vital for the structural integrity of the biofilm and its resistance to antibiotics and the host's immune response. Finally, the biofilm reaches a stage of dispersal where part of the matrix is broken down, allowing some bacteria to escape and potentially cause infections, known as nosocomial diseases, in healthcare settings.