Enterobacteriaceae

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Questions and Answers

Describe the general features of Enterobacteriales

Gram negative rods, straight, cylindrical, rounded ends, motile, non sporulating, simple nutritional requirements, facultative anaerobes, nitrate to nitrite, oxidase negative

What is the primary characteristic that differentiates fecal coliforms from general coliforms?

Fecal coliforms originate from the intestinal tract of warm-blooded animals. (correct)
Fecal coliforms have a higher resistance to environmental stress.
Fecal coliforms are found in non-lactose fermenting species.
Fecal coliforms are used as markers for water purification systems.

Which of the following coliforms is specifically known for its association with fecal contamination?

Enterobacter spp.
Escherichia coli (correct)
Citrobacter spp.
Klebsiella spp.

What is the significance of coliform bacteria in environmental testing?

They serve as markers for enteric contamination. (B) Signup and view all the answers

Which statement about coliform bacteria is false?

Coliforms are exclusively found in human feces. (D) Signup and view all the answers

Which of the following statements about the types of coliforms is true?

There are four main types of coliforms used as contamination markers. (C) Signup and view all the answers

Flashcards

Enterobacteriales: General Features

Gram-negative bacteria shaped like straight, cylindrical rods with rounded ends. They are motile, meaning they can move, and don't form spores. They have simple nutritional needs and can survive with or without oxygen (facultative anaerobes). They can convert nitrates to nitrites and lack the enzyme oxidase.

Coliforms

A group of bacteria in the Enterobacteriaceae family that can ferment lactose, making them useful as indicators of fecal contamination.

Fecal coliforms

A specific kind of coliform bacteria that comes exclusively from the intestines of warm-blooded animals.

Types of coliforms

Escherichia coli, Klebsiella spp., Enterobacter spp., and Citrobacter spp. are the four main types of coliforms.

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Why are fecal coliforms better indicators?

Fecal coliforms are considered a more reliable indicator of fecal contamination than general coliforms because they are found in higher concentrations in feces.

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What are coliforms used for?

They're used to detect fecal contamination in water, food, and other environments.

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Study Notes

Coliforms

Coliforms are a group of Enterobacteriaceae bacteria that ferment lactose (lactose positive).
They're used to indicate the presence of enteric contamination.
Four examples of coliforms are Escherichia coli, Klebsiella spp., Enterobacter spp., and Citrobacter spp.

Fecal Coliforms

Fecal coliforms are a subset of coliforms.
They specifically originate from the intestines of warm-blooded animals.
They're considered a better indicator of fecal contamination compared to general coliforms.
Fecal coliforms are found in higher concentrations in feces than other coliforms.