Coliform bacteria

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Distinguish from the birds called coliiforms.

Coliform bacteria are the commonly-used bacterial indicator of sanitary quality of foods and water. They are defined as rod-shaped Gram-negative non-spore forming organisms that ferment lactose with the production of acid and gas when incubated at 35-37°C. Coliforms are abundant in the feces of warm-blooded animals, but can also be found in the aquatic environment, in soil and on vegetation. In most instances, coliforms themselves are not the cause of sickness, but they are easy to culture and their presence is used to indicate that other pathogenic organisms of fecal origin may be present. Fecal pathogens include bacteria, viruses, protozoa or parasites.

Typical genera include:^[1]

• Citrobacter,
• Enterobacter,
• Escherichia,
• Hafnia,
• Klebsiella,
• Serratia and
• Yersinia.

Escherichia coli (E. coli), a rod-shaped member of the coliform group, can be distinguished from most other coliforms by its ability to ferment lactose at 44°C, and by its growth and colour reaction on certain types of culture media. Unlike the general coliform group, E. coli are almost exclusively of fecal origin and their presence is thus an effective confirmation of fecal contamination. Typically, E. coli are about 11% of the coliforms in human feces.^{[citation needed]}

[edit] See also

• Bacteriological water analysis
• Coliform Index
• Fecal coliforms
• Indicator bacteria

[edit] References