Podcast
Questions and Answers
Which structure of Enterobacteriaceae is classified by more than 150 different heat-stable somatic O antigens?
Which structure of Enterobacteriaceae is classified by more than 150 different heat-stable somatic O antigens?
Which characteristic is shared by most gram-negative enteric bacteria?
Which characteristic is shared by most gram-negative enteric bacteria?
What is a key factor for the identification of enteric bacteria?
What is a key factor for the identification of enteric bacteria?
Which member of the normal intestinal microbiota is considerably less common than E. coli?
Which member of the normal intestinal microbiota is considerably less common than E. coli?
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In which anatomical site can clinically important infections caused by enteric bacteria occur?
In which anatomical site can clinically important infections caused by enteric bacteria occur?
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Which of the following is NOT a member of the Enterobacteriaceae family?
Which of the following is NOT a member of the Enterobacteriaceae family?
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What is the natural habitat of Enterobacteriaceae?
What is the natural habitat of Enterobacteriaceae?
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Which Enterobacteriaceae organism is part of the normal microbiota and incidentally causes disease?
Which Enterobacteriaceae organism is part of the normal microbiota and incidentally causes disease?
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What type of organisms are the Enterobacteriaceae in terms of oxygen requirement?
What type of organisms are the Enterobacteriaceae in terms of oxygen requirement?
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Which characteristic is NOT possessed by Enterobacteriaceae?
Which characteristic is NOT possessed by Enterobacteriaceae?
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What is the natural habitat of the Enterobacteriaceae?
What is the natural habitat of the Enterobacteriaceae?
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Name three genera included in the family Enterobacteriaceae.
Name three genera included in the family Enterobacteriaceae.
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What type of microorganisms are the Enterobacteriaceae in terms of oxygen requirement?
What type of microorganisms are the Enterobacteriaceae in terms of oxygen requirement?
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What is a key characteristic of the Enterobacteriaceae's antigenic structure?
What is a key characteristic of the Enterobacteriaceae's antigenic structure?
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Which enteric organisms are part of the normal microbiota and incidentally cause disease?
Which enteric organisms are part of the normal microbiota and incidentally cause disease?
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What are the three types of antigens used for classification of Enterobacteriaceae?
What are the three types of antigens used for classification of Enterobacteriaceae?
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What are the shared characteristics of Enterobacteriaceae?
What are the shared characteristics of Enterobacteriaceae?
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What is the main anatomical site of clinically important infections caused by enteric bacteria?
What is the main anatomical site of clinically important infections caused by enteric bacteria?
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Which enteric bacteria are considerably less common than E. coli in the normal intestinal microbiota?
Which enteric bacteria are considerably less common than E. coli in the normal intestinal microbiota?
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When do the enteric bacteria become pathogenic?
When do the enteric bacteria become pathogenic?
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Study Notes
Enterobacteriaceae Overview
- Over 150 distinct heat-stable somatic O antigens classify the Enterobacteriaceae family.
- Most gram-negative enteric bacteria share an ability to ferment carbohydrates.
- Identification of enteric bacteria relies primarily on biochemical testing and antigenic structure.
Normal Intestinal Microbiota
- Enterobacter cloacae is a member of the normal intestinal microbiota, occurring less frequently than E. coli.
- Enteric bacteria can cause clinically important infections primarily in the gastrointestinal tract and urogenital tract.
Classification and Characteristics
- Vibrio cholerae is NOT part of the Enterobacteriaceae family, while Escherichia, Klebsiella, and Salmonella are included.
- The natural habitat of Enterobacteriaceae is primarily the intestines of humans and animals.
- Enterobacter cloacae is an example of an organism that is part of the normal microbiota but can lead to opportunistic infections.
Oxygen Requirements
- Enterobacteriaceae are facultatively anaerobic organisms, allowing them to grow in both aerobic and anaerobic environments.
- Enterobacteriaceae are characterized by being non-spore forming, which is not typical of many other bacterial families.
Antigenic Structure
- Enterobacteriaceae possess a complex antigenic structure featuring three major types of antigens: somatic (O), flagellar (H), and capsular (K) antigens.
- These antigens are crucial for classification and serotyping of various species within the family.
Pathogenicity and Infection
- Organisms like E. coli and Klebsiella can be part of the normal microbiota yet act as opportunistic pathogens under specific circumstances.
- Enteric bacteria become pathogenic often when they acquire virulence factors or when the host's barriers are compromised.
Shared Characteristics
- Shared traits of Enterobacteriaceae include being oxidase-negative, catalase-positive, and typically having glucose as a fermentation product.
- Clinically important infections due to enteric bacteria mainly occur in the intestines, urinary tract, and sometimes in bloodstream infections.
Rarity in Intestinal Microbiota
- Other enteric bacteria such as Enterobacter and Serratia are considerably less common than E. coli within the normal intestinal microbiota.
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Description
Test your knowledge on Enterobacteriaceae in Microbiology Week 6 with Dr. Beriwan A. Ali. This quiz covers the characteristics, classification, and medical significance of the Enterobacteriaceae family.
