Coliform bacteria: Difference between revisions
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{{distinguish|text=[[Coliiformes]], a family of birds, or [[Fecal coliform]], one type of coliform bacteria}} |
{{distinguish|text=[[Coliiformes]], a family of birds, or [[Fecal coliform]], one type of coliform bacteria}} |
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[[File:E coli at 10000x, original.jpg|thumb|''Escherichia coli'']] |
[[File:E coli at 10000x, original.jpg|thumb|''Escherichia coli'']] |
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'''Coliform bacteria''' are defined as [[ |
'''Coliform bacteria''' are defined as either [[motile]] or [[non-motile]] [[Gram-negative]] non-[[Endospore|spore forming]] [[Bacillus (shape)|Bacilli]] that possess [[Beta-galactosidase|β-galactosidase]] to produce acids and gases under their optimal growth temperature of 35-37°C.<u><ref>{{Citation |last=Li |first=Daoliang |title=Water Quality Monitoring in Aquaculture |date=2019 |url=http://dx.doi.org/10.1016/b978-0-12-811330-1.00012-0 |work=Water Quality Monitoring and Management |pages=303–328 |publisher=Elsevier |access-date=2022-03-03 |last2=Liu |first2=Shuangyin}}</ref></u> They can be aerobes or facultative aerobes, and are a commonly used [[Indicator bacteria|indicator]] of sanitary quality of foods and water.<ref>{{Cite journal |last=Martin |first=Nicole H. |last2=Trmčić |first2=Aljoša |last3=Hsieh |first3=Tsung-Han |last4=Boor |first4=Kathryn J. |last5=Wiedmann |first5=Martin |date=2016 |title=The Evolving Role of Coliforms As Indicators of Unhygienic Processing Conditions in Dairy Foods |url=https://pubmed.ncbi.nlm.nih.gov/27746769 |journal=Frontiers in Microbiology |volume=7 |pages=1549 |doi=10.3389/fmicb.2016.01549 |issn=1664-302X |pmc=5043024 |pmid=27746769}}</ref> Coliforms can be found in the aquatic environment, in soil and on vegetation; they are universally present in large numbers in the feces of [[warm-blooded]] animals as they are known to inhabit the gastrointestinal system.<ref name=":02">{{Citation |last=Li |first=Daoliang |title=Chapter 12 - Water Quality Monitoring in Aquaculture |date=2019-01-01 |url=https://www.sciencedirect.com/science/article/pii/B9780128113301000120 |work=Water Quality Monitoring and Management |pages=303–328 |editor-last=Li |editor-first=Daoliang |publisher=Academic Press |language=en |doi=10.1016/b978-0-12-811330-1.00012-0 |isbn=978-0-12-811330-1 |access-date=2022-03-23 |last2=Liu |first2=Shuangyin |editor2-last=Liu |editor2-first=Shuangyin}}</ref> While coliform bacteria are not normally causes of serious illness, they are easy to [[Microbiological culture|culture]], and their presence is used to infer that other [[Pathogen|pathogenic]] organisms of fecal origin may be present in a sample, or that said sample is not safe to consume.<ref name=":02" /> Such pathogens include disease-causing [[bacteria]], [[viruses]], or [[protozoa]] and many multicellular [[Parasite|parasites]].<ref name=":02" /> |
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Typical genera include:<ref>''The Microbiology of Drinking Water (2002) – Part 1 -(h2o) Water Quality and Public Health''; '''Department of the Environment'''</ref> |
Typical genera include:<ref>''The Microbiology of Drinking Water (2002) – Part 1 -(h2o) Water Quality and Public Health''; '''Department of the Environment'''</ref> |
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*''[[Citrobacter]]'' |
*''[[Citrobacter]]'' |
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*''[[Enterobacter]]'' |
*''[[Enterobacter]]'' |
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*''[[Hafnia (bacterium)|Hafnia]]'' |
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*''[[Klebsiella]]'' |
*''[[Klebsiella]]'' |
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*''[[Escherichia]]'' |
*''[[Escherichia]]'' |
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Revision as of 17:54, 24 March 2022
Coliform bacteria are defined as either motile or non-motile Gram-negative non-spore forming Bacilli that possess β-galactosidase to produce acids and gases under their optimal growth temperature of 35-37°C.[1] They can be aerobes or facultative aerobes, and are a commonly used indicator of sanitary quality of foods and water.[2] Coliforms can be found in the aquatic environment, in soil and on vegetation; they are universally present in large numbers in the feces of warm-blooded animals as they are known to inhabit the gastrointestinal system.[3] While coliform bacteria are not normally causes of serious illness, they are easy to culture, and their presence is used to infer that other pathogenic organisms of fecal origin may be present in a sample, or that said sample is not safe to consume.[3] Such pathogens include disease-causing bacteria, viruses, or protozoa and many multicellular parasites.[3]
Typical genera include:[4]
Escherichia coli (E. coli) can be distinguished from most other coliforms by its ability to ferment lactose at 44 °C in the fecal coliform test, and by its growth and color reaction on certain types of culture media. When cultured on an eosin methylene blue (EMB) plate, a positive result for E. coli is metallic green colonies on a dark purple medium. Also can be cultured on Tryptone Bile X-Glucuronide (TBX) to appear as blue or green colonies after incubation period of 24 hours. Escherichia coli have an incubation period of 12–72 hours with the optimal growth temperature being 37 °C. Unlike the general coliform group, E. coli are almost exclusively of fecal origin and their presence is thus an effective confirmation of fecal contamination. Most strains of E. coli are harmless, but some can cause serious illness in humans. Infection symptoms and signs include bloody diarrhea, stomach cramps, vomiting and occasionally, fever. The bacteria can also cause pneumonia, other respiratory illnesses and urinary tract infections.[5][6]
An easy way to differentiate between different types of coliform bacteria is by using an eosin methylene blue agar plate.[7] This plate is partially inhibitory to Gram (+) bacteria, and will produce a color change in the Gram (-) bacterial colonies based on lactose fermentation abilities.[7] Strong lactose fermenters will appear as dark blue/purple/black, and E.coli (which also ferments lactose) colonies will be dark colored, but will also appear to have a metallic green sheen. Other coliform bacteria will appear as thick, slimy colonies, with non-fermenters being colorless, and weak fermenters being pink.[citation needed]
See also
- Bacteriological water analysis
- Coliform index
- Fecal coliform
- Indicator bacteria
- Pathogenic Escherichia coli
References
- ^ Li, Daoliang; Liu, Shuangyin (2019), "Water Quality Monitoring in Aquaculture", Water Quality Monitoring and Management, Elsevier, pp. 303–328, retrieved 2022-03-03
- ^ Martin, Nicole H.; Trmčić, Aljoša; Hsieh, Tsung-Han; Boor, Kathryn J.; Wiedmann, Martin (2016). "The Evolving Role of Coliforms As Indicators of Unhygienic Processing Conditions in Dairy Foods". Frontiers in Microbiology. 7: 1549. doi:10.3389/fmicb.2016.01549. ISSN 1664-302X. PMC 5043024. PMID 27746769.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ a b c Li, Daoliang; Liu, Shuangyin (2019-01-01), Li, Daoliang; Liu, Shuangyin (eds.), "Chapter 12 - Water Quality Monitoring in Aquaculture", Water Quality Monitoring and Management, Academic Press, pp. 303–328, doi:10.1016/b978-0-12-811330-1.00012-0, ISBN 978-0-12-811330-1, retrieved 2022-03-23
- ^ The Microbiology of Drinking Water (2002) – Part 1 -(h2o) Water Quality and Public Health; Department of the Environment
- ^ Todar, K. "Pathogenic E. coli". Online Textbook of Bacteriology. University of Wisconsin–Madison Department of Bacteriology. Retrieved 2007-11-30.
- ^ "Escherichia coli". CDC National Center for Emerging and Zoonotic Infectious Diseases. Retrieved 2012-10-02.
- ^ a b Leininger, Dagny Jayne; Roberson, Jerry Russel; Elvinger, François (May 2001). "Use of Eosin Methylene Blue Agar to Differentiate Escherichia Coli from Other Gram-Negative Mastitis Pathogens". Journal of Veterinary Diagnostic Investigation. 13 (3): 273–275. doi:10.1177/104063870101300319. ISSN 1040-6387.