In nature, bacteria exist in highly-coordinated structures known as biofilms. These densely-packed microbial communities develop when free-swimming (planktonic) cells attach to a surface and form mushroom-like structures containing stalks, a meshwork of channels, and encased in a layer of slime comprising proteins, polysaccharides, and DNA. Consequently, this bacterial fortress is notoriously resistant to antimicrobial agents, rendering biofilms virtually untreatable. In patients with cystic fibrosis, Pseudomonas aeruginosa biofilms establish chronic lung infections. Similarly, biofilms formed on indwelling catheters or water intake pipes are the scourge of medical personnel and engineers who can't eradicate them.