Questions and Answers
Which of the following is true about Enterobacteriaceae?
What is the common term used to refer to the Family Enterobacteriaceae?
Which of the following is NOT one of the four major features shared by Enterobacteriaceae?
Which of the following Enterobacteriaceae is NOT included in the list of non-motile organisms?
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What is the biochemical test used to distinguish Enterobacteriaceae from other Gram-negative bacteria?
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What is the value of colony morphology on BAP or CA in distinguishing Enterobacteriaceae?
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Which of the following media are used for the initial evaluation of colonies of Enterobacteriaceae?
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Which of the following is not true about Enterobacteriaceae?
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What is the basis of classification for Enterics?
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How are species further grouped within each Tribe?
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What is the purpose of grouping Enterobacteriaceae into Tribes?
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Which of the following is not a part of the Enterobacteriaceae classification system?
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What is the O antigen in enteric bacteria?
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Which of the following contributes to the pathogenicity of enteric bacteria?
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What is the H antigen in enteric bacteria?
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Which of the following is a heat-labile antigen in enteric bacteria?
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What is the function of plasmids in enteric bacteria?
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Which of the following antigens is located in the cell wall of enteric bacteria?
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What is the meaning of 'fecal coliforms' in reference to Enterics?
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Where can Enterics be found besides the intestinal tract of animals and humans?
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Study Notes
Overview of Enterobacteriaceae
- Enterobacteriaceae are classified as Gram-negative bacilli and do not form spores.
- Commonly referred to as "Enterics," the family includes various pathogenic and non-pathogenic species.
Key Features of Enterobacteriaceae
- Major characteristics: ferment glucose and reduce nitrates to nitrites.
- Enterobacteriaceae are predominantly oxidase-negative, with motility varied among species.
Identification and Biochemical Testing
- Escherichia species are motile, while Klebsiella, Shigella, and Yersinia are non-motile.
- The nitrate reduction test is vital for distinguishing Enterobacteriaceae from other Gram-negative bacteria.
- Colony morphology on Blood Agar Plates (BAP) or Chocolate Agar (CA) has limited value, primarily helpful for identifying Klebsiella.
Media for Primary Evaluation
- Initial colony evaluation typically involves media like MacConkey, Hektoen Enteric (HE), and Xylose Lysine Deoxycholate (XLD) agars.
Classification Structure
- Enterobacteriaceae are classified into tribes, simplifying their classification based on shared characteristics.
- Further grouping within each tribe is based on biochemical characteristics, not colony morphology.
Antigenic Components
- The O antigen is a somatic, heat-stable component found in the cell wall.
- The H antigen serves as a flagellar antigen, while K antigens are part of the capsule.
- Heat-labile antigens include both H and K types.
Pathogenicity Factors
- Pathogenic enteric bacteria often possess the ability to invade tissues, contrasting with non-pathogenic species.
- Plasmids in enteric bacteria confer antibiotic resistance, critical for their survival.
Environmental Presence
- Fecal coliforms refer to Enterics found in feces of animals and humans, highlighting their significance in health and sanitation.
- Beyond intestinal habitats, Enterics can also be located in soil and water, contributing to their environmental resilience and distribution.
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Description
Test your knowledge on Enterobacteriaceae with these multiple-choice questions. This quiz covers key characteristics, classifications, and terms related to this important family of bacteria. Perfect for students in microbiology courses.
