Questions and Answers
To which class of Proteobacteria do Enterobacteriaceae belong?
Gamma (ɣ)
What is the Linnaean classification of Enterobacteriaceae?
Family
How many genera and species are in the Enterobacteriaceae?
51 genera with between 1 and 22 species per genus
Where are Enterobacteriaceae found?
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How many chromosomes do Enterobacteriaceae have?
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What is the size range of the single chromosome of Enterobacteriaceae?
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Which have the bigger genome: endosymbionts or non-endosymbionts?
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Do endosymbionts have a lower or higher G+C content than others?
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What is the definition of an endosymbiont?
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What is the definition of a non-endosymbiont?
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Approximately how many strains of Enterobacteriaceae contain extra-chromosomal DNA in the form of plasmids?
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Are Enterobacteriaceae Gram-negative?
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Are Enterobacteriaceae oxidase positive?
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Can Enterobacteriaceae ferment glucose?
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Can Enterobacteriaceae reduce nitrate to nitrite?
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What type of respiring organisms are Enterobacteriaceae?
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What type of respiratory bacteria are Enterobacteriaceae?
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Are Enterobacteriaceae motile and if so, how do they move?
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Where are Enterobacteriaceae naturally found?
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How are Enterobacteriaceae bacteria usually spread?
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Give the 4 key genera within the Enterobacteriaceae studied in lectures.
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What are the 5 routes of infection of Enterobacteriaceae?
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Which 2 Enterobacteriaceae cause gastrointestinal infections?
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Which Enterobacteriaceae cause urinary tract infections and abdominal abscesses?
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Which strain of E. coli can be spread from person-to-person?
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What are the 3 ways Enterobacteriaceae enter the body through parenteral routes?
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Which member of Enterobacteriaceae can also enter the body through the respiratory route?
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What disease does Y. pestis cause?
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Study Notes
Enterobacteriaceae Overview
- Belong to the Gamma (ɣ) class of Proteobacteria.
- Classified as a family within the Linnaean taxonomy.
Genera and Species
- Comprise 51 genera with 1 to 22 species per genus.
- Ubiquitous in terrestrial and aquatic environments; often associated with animals, plants, or insects.
Genomic Characteristics
- Have a single chromosome ranging in size from 0.4 Mbp to 6.4 Mbp.
- Non-endosymbionts typically have larger genomes compared to endosymbionts.
- Endosymbionts possess lower G+C content (20-29%) than other Enterobacteriaceae (39-60%).
Cellular and Biochemical Properties
- Gram-negative, spore-forming rods (bacilli); oxidase negative.
- Capable of fermenting glucose; gas production may vary.
- Can reduce nitrate to nitrite with few exceptions.
- Are facultative anaerobes, thriving in both aerobic and anaerobic conditions.
Motility and Natural Habitat
- Most are motile, using peritrichous flagella; exceptions include Shigella and Klebsiella.
- Naturally found in the gastrointestinal tracts of hosts (humans, animals, insects) and in the environment (soil, water, plants, food).
Transmission Routes
- Commonly spread via fecal-oral routes.
- Infection routes include gastrointestinal ingestion, endogenous infections (e.g., UTIs), person-to-person contact, parenteral methods (injections, surgery, bites), and respiratory droplets.
Key Genera and Infections
- Main genera of study: Escherichia, Shigella, Salmonella, and Yersinia.
- Salmonella and E.coli O157:H7 are notable for causing gastrointestinal infections.
- Uropathogenic E.coli (UPEC) is associated with urinary tract infections and abdominal abscesses.
- E.coli K1 strain can spread between individuals.
Parenteral Infection Routes
- Enterobacteriaceae can enter through injections, surgical procedures, and insect bites.
- Yersinia pestis can also spread via respiratory droplets, leading to pneumonic plague.
Specific Diseases
- Yersinia pestis is the causative agent of pneumonic plague.
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Test your knowledge on Enterobacteriaceae with these flashcards. Explore key concepts including their classification, genera, and habitats. Perfect for students and professionals in the field of microbiology.
