Coliform bacteria: Difference between revisions

Latest revision as of 01:03, 20 February 2025

Group of bacteria found in the environment, foods, and intestines of people and animals

Coliform bacteria are a group of Gram-negative bacteria that are commonly found in the environment, including soil, water, and vegetation, as well as in the feces of warm-blooded animals. They are used as indicator organisms to assess the sanitary quality of foods and water. The presence of coliform bacteria in drinking water suggests that there may be a pathway for pathogens to enter the water supply.

Characteristics[edit]

Coliform bacteria are rod-shaped, non-spore forming, and motile or non-motile. They are facultative anaerobes, meaning they can survive in both aerobic and anaerobic environments. Coliforms ferment lactose with the production of acid and gas when incubated at 35-37°C.

Types of Coliforms[edit]

Coliform bacteria are divided into three groups:

Total coliforms: This group includes all coliform bacteria, which are found in the environment and feces.
Fecal coliforms: A subset of total coliforms, fecal coliforms are more specifically associated with fecal contamination. Escherichia coli (E. coli) is the most well-known fecal coliform.
E. coli: A specific species of fecal coliform bacteria, E. coli is often used as a specific indicator of fecal contamination.

Significance in Water Quality[edit]

The presence of coliform bacteria in water is used as an indicator of potential contamination by fecal material and the possible presence of pathogenic organisms. Water quality testing for coliforms is a standard practice in public health to ensure safe drinking water.

Testing for Coliforms[edit]

Several methods are used to detect coliform bacteria in water, including:

Multiple-tube fermentation technique: This method involves inoculating a series of tubes with water samples and observing gas production.
Membrane filtration: Water is filtered through a membrane that retains bacteria, which are then cultured on selective media.
Enzyme substrate tests: These tests use substrates that change color or fluoresce in the presence of coliforms.

Health Implications[edit]

While coliform bacteria themselves are not typically pathogenic, their presence indicates that other harmful bacteria, viruses, or parasites may be present. This can lead to gastrointestinal illnesses and other health issues.

Also see[edit]

References[edit]

E. coli at 10000x
Coliform bacteria on Levine EMB agar

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-[[Coliform bacteria]] represent a broad class of gram-negative, non-spore forming, rod-shaped bacteria. These microorganisms, which predominantly reside in the digestive tracts and feces of animals and humans, can also be found in soil, vegetation, and various water sources. Certain strains can pose significant health risks, while others serve as vital indicators of fecal contamination in water systems.
+{{Short description|Group of bacteria found in the environment, foods, and intestines of people and animals}}
+{{Infobox bacteria
+| name = Coliform bacteria
+| image = E coli at 10000x, original.jpg
+| image_caption = ''Escherichia coli'' at 10,000x magnification
+| domain = [[Bacteria]]
+| phylum = [[Proteobacteria]]
+| classis = [[Gammaproteobacteria]]
+| ordo = [[Enterobacterales]]
+| familia = [[Enterobacteriaceae]]
+}}
-== Characteristics and Classification ==
+'''Coliform bacteria''' are a group of [[Gram-negative]] bacteria that are commonly found in the environment, including soil, water, and vegetation, as well as in the feces of warm-blooded animals. They are used as indicator organisms to assess the sanitary quality of foods and water. The presence of coliform bacteria in drinking water suggests that there may be a pathway for pathogens to enter the water supply.
-Coliforms are facultative anaerobic bacteria, meaning they can thrive in both oxygen-rich and oxygen-poor environments. They ferment lactose to produce gas and acid, a characteristic that aids in their identification in laboratory tests.
+==Characteristics==
+Coliform bacteria are rod-shaped, non-spore forming, and motile or non-motile. They are facultative anaerobes, meaning they can survive in both aerobic and anaerobic environments. Coliforms ferment lactose with the production of acid and gas when incubated at 35-37°C.
-Coliforms are further categorized into two groups: total coliforms and fecal coliforms. Total coliforms include bacteria found in the soil, water, and human or animal waste. Fecal coliforms, such as Escherichia coli (E. coli), are a subgroup of total coliforms that primarily inhabit the intestines of warm-blooded animals.
+==Types of Coliforms==
+Coliform bacteria are divided into three groups:
-== Role in Disease and Public Health ==
+* '''Total coliforms''': This group includes all coliform bacteria, which are found in the environment and feces.
+* '''Fecal coliforms''': A subset of total coliforms, fecal coliforms are more specifically associated with fecal contamination. ''[[Escherichia coli]]'' (''E. coli'') is the most well-known fecal coliform.
+* '''E. coli''': A specific species of fecal coliform bacteria, ''E. coli'' is often used as a specific indicator of fecal contamination.
-While many coliform bacteria are harmless, some strains like E. coli O157:H7 can cause serious foodborne illnesses. Symptoms range from diarrhea and abdominal cramps to life-threatening conditions such as hemolytic-uremic syndrome.
+==Significance in Water Quality==
+The presence of coliform bacteria in water is used as an indicator of potential contamination by fecal material and the possible presence of pathogenic organisms. Water quality testing for coliforms is a standard practice in public health to ensure safe drinking water.
-In public health, the presence of coliforms in water supplies often indicates fecal contamination and the potential presence of pathogenic (disease-causing) bacteria, viruses, and parasites. Regular testing for coliform bacteria is a standard measure for ensuring the safety of drinking water.
+==Testing for Coliforms==
+Several methods are used to detect coliform bacteria in water, including:
-== Economic Impact on Livestock Industry ==
+* '''Multiple-tube fermentation technique''': This method involves inoculating a series of tubes with water samples and observing gas production.
+* '''Membrane filtration''': Water is filtered through a membrane that retains bacteria, which are then cultured on selective media.
+* '''Enzyme substrate tests''': These tests use substrates that change color or fluoresce in the presence of coliforms.
-Certain coliform bacteria, notably E. coli, can cause diseases in livestock, leading to economic losses due to decreased productivity, treatment costs, and animal mortality.
+==Health Implications==
+While coliform bacteria themselves are not typically pathogenic, their presence indicates that other harmful bacteria, viruses, or parasites may be present. This can lead to gastrointestinal illnesses and other health issues.
-[[Category:Bacteriology]]
+==Also see==
-[[Category:Public Health]]
+* [[Escherichia coli]]
-[[Category:Microbiology]]
+* [[Water quality]]
+* [[Microbial contamination]]
+* [[Public health]]
-== References ==
+==References==
-<references/>
+* [https://www.cdc.gov/healthywater/drinking/public/water_quality.html CDC - Water Quality]
-# "Coliform Bacteria." Water Research Center. [https://www.water-research.net/index.php/coliform-bacteria]
+* [https://www.epa.gov/dwstandardsregulations EPA - Drinking Water Regulations]
-# "Coliform Bacteria and Drinking Water." Centers for Disease Control and Prevention (CDC). [https://www.cdc.gov/healthywater/drinking/public/water_diseases.html#three]
-# "E. coli in Livestock." PennState Extension. [https://extension.psu.edu/e-coli-in-livestock]
+[[Category:Enterobacteriaceae]]
-# "Understanding and Managing E. coli O157:H7 in Feedlot Cattle." Journal of Animal Science. [https://academic.oup.com/jas/article/77/1/1/4641451]
+[[Category:Water quality indicators]]
-{{stub}}
+[[Category:Public health]]
+<gallery>
+File:E coli at 10000x, original.jpg|E. coli at 10000x
+File:Coli levine.JPG|Coliform bacteria on Levine EMB agar
+</gallery>