What Are Biofilms?

Biofilms are a complex community of microorganisms that adhere to a surface and are embedded in a matrix of extracellular polymeric substances (EPS), a glue-like substance microorganisms produce to stick together.

The microorganisms have various shapes and lengths. For its shapes, it includes spheres, rods, spirals, corkscrews, and so on. They are typically about 1 centimeter long and ten of thousands times smaller, which are invisible to our naked eyes. 

The fact that they stick together implies that they love to live in colonies too. It is like a fortress that is impenetrable by antibiotics.