Coloured scanning electron micrograph (SEM) of biofilms. An accumulations of microorganisms of mono- or poly-microbial aggregates are commonly referred to as a biofilm and can consist of diverse communities of bacteria. Biofilms have great importance for public health because of their role in certain infectious diseases and importance in a variety of device-related infections. Here one biofilm is protruding through a biofilm above it. Magnification: x3500 when printed at 10cm wide.