Biofilms are organized communities of microorganisms that exist in virtually every natural environment. Biofilms form in response to shear force (flow) to avert being removed from their environment by “turning on” specific genes responsible for biofilm growth. Biofilm formation is a process involving several steps: migration, attachment, layering
Once formed, microbial and bacterial biofilms are difficult to remove as they show an inherent lack of susceptibility to biocides and antibiotics when compared to planktonic (free-floating) microorganisms. Many studies have shown greater than a thousand-fold resistance to antibiotics by biofilms when compared to the same bacteria in a planktonic state.
When contemplating situations where bacterial biofilms would be expected to grow, it becomes obvious why they are so common. The two requirements for growth, 1)