Last update:
28-Dec-2007

Microorganisms do not οnly exist as free-floating cells, but are commonly attached to either an inert or a living surface (sessile bacteria). They produce an extracellular polymere and, with other components create complex structures, called biofilms. Biofilms, although common, are not a well-known entity. They grow wherever sufficient moisture is present: in the kitchen, on the interior surface of water pipes, on contact lenses. The gel-like film on the inside of a flower vase, the slippery slime on river stones, and the plaque on teeth are all biofilms. The appearance of biofilms depends on the species of microorganisms and their growing environment. The sessile bacteria have advantages compared to the planktonics regarding utilization of nutrients and protection from biocides. When bacteria are attached to a surface, a new phenotype appears, with the following main properties: different metabolism, increased resistance to antibiotics and disinfectants, increased exchange of genetic material, communication via special molecules-signals. The consequences of the development of biofilms for health and other processes of life are of such importance that further study is necessary in order to exploit or control them.

Key words: Biofilms, Human environment, Legionella spp, Water supply system.