Bacteria and E. Coli and Water
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Water, like everything else on Earth, including you, is full of bacteria. Some bacteria are beneficial and some are not. Escherichia coli (E. coli) bacteria, found in the digestive tract of animals, can get into the environment, and if contacted by people, can cause health problems and sickness. Find out the details here.
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Bacteria and E. Coli in Water
Credit: U.S. Environmental Protection Agency
Bacteria are common single-celled organisms and are a natural component of lakes, rivers, and streams. Most of these bacteria are harmless to humans; however, certain bacteria, some of which normally inhabit the intestinal tract of warm-blooded animals, have the potential to cause sickness and disease in humans. High numbers of harmless bacteria can be associated with harmful bacteria as well as other disease-causing organisms such as viruses and protozoans.
One method of determining how many bacteria are present is to count the number of bacteria colonies that grow on a prepared medium.
Escherichia coli (abbreviated as E. coli) are a diverse group of bacteria found in the environment, foods, and intestines of people and animals. . Although most strains of E. coli are harmless, others can make you sick. Some kinds of E. coli can cause diarrhea, while others cause urinary tract infections, respiratory illness and pneumonia, and other illnesses.
Total coliform
Coliforms are gram-negative, aerobic or faculative anaerobic, nonspore forming bacteria that are shaped like rods. These bacteria were originally believed to indicate the presence of fecal contamination. However coliforms have been found to be widely distributed in nature and are not always associated with the gastrointestinal tract of warm-blooded animals. None-the-less, the number of total coliform bacteria in the environment is still widely used as an indicator for potable (drinkable) water in the U.S.
Fecal coliform
Fecal coliform bacteria are a subgroup of coliform bacteria that were used to establish the first microbial water quality criteria. The ability to grow at an elevated temperature (44.5 degrees Celsius) separate these bacteria from all the coliforms captured in total coliforms and make it a more accurate indicator of fecal contamination by warm-blooded animals. Fecal-coliform bacteria are detected by counting the dark-blue to blue-grey colonies that grow on 0.65 micron filter placed on m-faekal Coliform (mFC) agar incubated in a 44.5º C oven for 22-24 hours. The presence of fecal coliforms in water indicates that fecal contamination of the water by a warm-blooded animal. However, recent studies have found that measuring fecal coliform concentrations do not provide a good indication of when swimmers will get sick.
E. coli
Escherichia coli (E. coli) is a rod-shaped bacterium commonly found in the gastrointestinal tract and feces of warm-blooded animals. It is a member of the fecal coliform group of bacteria and is distinguished by its inability to break down urease. E. coli numbers in freshwater are determined by counting the number of yellow and yellowbrown colonies growing on a 0.45 micron filter placed on m-TEC media and incubated at 35.0 ºC for 22-24 hours. The addition of urea substrate confirms that colonies are E. coli. This bacterium is a preferred indicator for determining the safety of freshwater recreation and its presence provides direct evidence of fecal contamination from warm-blooded animals. Although usually harmless, E. coli can cause illnesses such as meningitis, septicemia, urinary tract, and intestinal infections. One strain of E. coli, E. coli 0157:H7, can cause severe disease and may be fatal in high risk groups.
The relation between bacteria counts and sickness
Consumption of or contact with water contaminated with feces of warm-blooded animals can cause a variety of illnesses. Minor gastrointestinal discomfort is probably the most common symptom; however, pathogens that may cause only minor sickness in some people may cause serious conditions or death in others, especially in the very young, old, or those with weakened immunological systems.
Water, like everything else on Earth, including you, is full of bacteria. Some bacteria are beneficial and some are not. Escherichia coli (E. coli) bacteria, found in the digestive tract of animals, can get into the environment, and if contacted by people, can cause health problems and sickness. Find out the details here.
• Water Science School HOME • Water Quality topics •
Bacteria and E. Coli in Water
Credit: U.S. Environmental Protection Agency
Bacteria are common single-celled organisms and are a natural component of lakes, rivers, and streams. Most of these bacteria are harmless to humans; however, certain bacteria, some of which normally inhabit the intestinal tract of warm-blooded animals, have the potential to cause sickness and disease in humans. High numbers of harmless bacteria can be associated with harmful bacteria as well as other disease-causing organisms such as viruses and protozoans.
One method of determining how many bacteria are present is to count the number of bacteria colonies that grow on a prepared medium.
Escherichia coli (abbreviated as E. coli) are a diverse group of bacteria found in the environment, foods, and intestines of people and animals. . Although most strains of E. coli are harmless, others can make you sick. Some kinds of E. coli can cause diarrhea, while others cause urinary tract infections, respiratory illness and pneumonia, and other illnesses.
Total coliform
Coliforms are gram-negative, aerobic or faculative anaerobic, nonspore forming bacteria that are shaped like rods. These bacteria were originally believed to indicate the presence of fecal contamination. However coliforms have been found to be widely distributed in nature and are not always associated with the gastrointestinal tract of warm-blooded animals. None-the-less, the number of total coliform bacteria in the environment is still widely used as an indicator for potable (drinkable) water in the U.S.
Fecal coliform
Fecal coliform bacteria are a subgroup of coliform bacteria that were used to establish the first microbial water quality criteria. The ability to grow at an elevated temperature (44.5 degrees Celsius) separate these bacteria from all the coliforms captured in total coliforms and make it a more accurate indicator of fecal contamination by warm-blooded animals. Fecal-coliform bacteria are detected by counting the dark-blue to blue-grey colonies that grow on 0.65 micron filter placed on m-faekal Coliform (mFC) agar incubated in a 44.5º C oven for 22-24 hours. The presence of fecal coliforms in water indicates that fecal contamination of the water by a warm-blooded animal. However, recent studies have found that measuring fecal coliform concentrations do not provide a good indication of when swimmers will get sick.
E. coli
Escherichia coli (E. coli) is a rod-shaped bacterium commonly found in the gastrointestinal tract and feces of warm-blooded animals. It is a member of the fecal coliform group of bacteria and is distinguished by its inability to break down urease. E. coli numbers in freshwater are determined by counting the number of yellow and yellowbrown colonies growing on a 0.45 micron filter placed on m-TEC media and incubated at 35.0 ºC for 22-24 hours. The addition of urea substrate confirms that colonies are E. coli. This bacterium is a preferred indicator for determining the safety of freshwater recreation and its presence provides direct evidence of fecal contamination from warm-blooded animals. Although usually harmless, E. coli can cause illnesses such as meningitis, septicemia, urinary tract, and intestinal infections. One strain of E. coli, E. coli 0157:H7, can cause severe disease and may be fatal in high risk groups.
The relation between bacteria counts and sickness
Consumption of or contact with water contaminated with feces of warm-blooded animals can cause a variety of illnesses. Minor gastrointestinal discomfort is probably the most common symptom; however, pathogens that may cause only minor sickness in some people may cause serious conditions or death in others, especially in the very young, old, or those with weakened immunological systems.