Biofilms in drinking water represent a clear risk to public health.
Materials such as cast iron, galvanised steel, stainless steel, copper and polyethylene are used to manufacture water distribution pipes. It is worth noting that all these materials favour biofilm formation.
Proteobacteria are the dominant group of microbes in natural water systems, and in freshwater or potable water distribution networks. The development of biofilms inside water distribution pipes encourages the propagation of mixed microbial populations and is considered the main source of bacteria in water supply systems.
The pathogenic bacterium, Escherichia coli, and other members of the Enterobacteriaceae, can appear in water supply systems as contaminants due to flooding, water supply failure, or insufficient disinfection. Other opportunistic bacteria such as Pseudomonas aeruginosa, Burkholderia spp., Stenotrophomonas maltophilia and Legionella spp. are also detected quite frequently. They increase the health risks associated with consumption of water.
Please also see here for information on biofilms in water distribution systems.
Image (left): Escherichia coli biofilm on a surface of polyether ether ketone (PEEK) after 24 hours growth. When threatened, cells in the biofilm begin rapidly mutating; the outer layer of the biofilm becomes thicker to protect the bacteria.
Image (right): Confocal microscopy image of Escherichia coli biofilm on a surface of PEEK reinforced with glass fibres after 24 hours growth. The bacteria within biofilm is more resistant to antibiotics and disinfectants than bacteria found outside of the biofilm.
Both images were provided by Dimitra Tsaroucha of the University of Bradford.
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