Enterococcus are sphere-shaped bacteria (coccus) which are part of the normal intestinal flora of the large intestine (Greek: enteron = intestine) in humans and numerous mammals, as well as birds; thus, they are referred to as Enterococcus.
These bacteria were first grown from stool samples in 1899. Should the bacteria start spreading from the intestine, this could lead to infections of the urinal tract, peritonitis and, in rare cases – when the bacteria enter the bloodstream or in the case of damaged heart valves – to endocarditis.
Enterococcus play a role in fermentation and maturing processes in foods (e.g. Camembert and goat’s cheese). As these bacteria can be found in the stool of humans and animals on a regular basis, they are classified as indicators for the pollution of bathing waters with faeces.
E. coli is also used as an indicator for faeces pollution, in addition to enterococcus. Faecal pollution could lead to infections via the importing of obligatory pathogenic microorganisms (e.g. stool from people with hepatitis A viruses).
Enterococcus are analysed in drinking water, swimming pool and bathing waters on a regular basis in line with the given legal regulations. The detection of enterococcus indicates a high probability of faecal pollution, which means that the water might be contaminated with pathogenic microorganisms (bacteria, viruses, parasites). There are parameters (limits) of 0 to 100 ml in place for drinking water -- i.e. no enterococcus must be detected in 100 ml of water.
The water supplier must undertake immediate measures to restore perfect drinking water quality, as soon as enterococcus are detected in drinking water. In such cases, the disinfection of the drinking water using appropriate and admitted disinfectants (e.g. chlorine, chlorine dioxide, sodium hypochlorite) is required.
Water supply companies are legally obliged – in line with the Austrian Drinking Water Regulation -- to inform their customers of the situation and any preventative measures (e.g. limited use of water or specific treatment methods such as boiling the water for at least three minutes, if microbiological requirements were not met). Furthermore, commercial customers must be informed that this information must be made available to all end-consumers in an appropriate manner (e.g. poster on a noticeboard in a building).
Bacteriological tests are required following the completion of the disinfection process to assess the success of the actions taken.