Enteric Bacteria (EXAM III) Flashcards
Shape & gram stain of enteric bacteria:
Gram negative bacilli
Some enteric bacteria are common members of:
Human & animal flora
Some enteric bacteria are members of commensal groups that have become ______ due to _____
Pathogenic due to acquired virulence factors
What are some of the acquired virulence factors causing some commensal enteric bacteria to become pathogenic?
- Toxins from plasmids
- Toxins from bacteriophages
- Pathogenicity islands
Most enteric bacteria can be motile due to:
Peritrichous flagella (H-antigen)
Some enteric bacteria are non-motile such as:
- Shigella
- Klebsiella
- Yersinia
Most enteric bacteria have _____ on the surface
Surface pili
Responsible for adherence in enteric bacteria:
Fimbriae
Responsible for plasmid conjugation in enteric bacteria:
Sex pili
Some enteric species have ____ such as K or Vi antigen
Capsules
Some enteric species have capsules such as:
K or Vi antigen
List the enteric bacterial species that contain capsules:
- Most Klebsiella species
- Some enterobacter species
- Somen Ecoli species
All enteric bacterial species contain:
Outer membrane LPS
The outer membrane LPS found in all enteric bacterial species may be referred to as:
Heat-stable endotoxin
All enteric bacterial species contain LPS (heat-stable endotoxin) with:
Enterobacterial common antigen and serotype-specific O-antigen
Because enteric bacteria are ______ they can survive when expelled in feces
Facultative anaerobes
The enteric bacterial species that contain a capsule use this as an important:
Virulence factor
Why do all enteric bacterial species contain an outer membrane with LPS?
Because they are gram NEGATIVE bacteria
The characterization of various pathogenic E. coli strains is based on:
Toxins produced
A lot of pathogenic enteric bacterial species result in:
GI issues
When enteric bacteria have a toxin like _____ toxin it leads to watery diarrhea
Cholera toxin
When enteric bacteria have a toxin like _____ toxin it leads to bloody diarrhea
Shiga
When enteric bacterial infection also involves neutrophils & inflammation, what may result?
Pus in diarrhea
When enteric bacterial infection results in pus in diarrhea caused by neutrophil & inflammatory involvement:
Dysentery
Transmission of pathogenic enteric bacterial species causing diarrhea, bloody diarrhea & dysentery are transmitted by:
Person-to-person
The āseven Fāsā
What are the seven Fās of transmission?
Feces, food, fluids, fingers, flies, fomites & fornication
What is the enterobacterial common antigen:
Outer- and inner-core sugars
The outer- and inner-core sugars of enterobacterial species is referred to as:
Enterobacterial common antigen
The LPS found in enterobacteria is also referred to as:
Heat-stable enterotoxin
When must we consider that the LPS found in enterobacteria is a heat-stable enterotoxin?
Becomes important when considering sterilization
Is present in many bacteria like Yersinia, Salmonella, Shigella, Enteropathogenic EPEC (E. coli); also present other species like Pseudomonas and Chlamydia:
Type III secretion system
List the enterobacterial pathogenic species that utilize the a Type III secretion system:
- Yersinia
- Salmonella
- Shigella
- Enteropathogenic EPEC E. coli
List the non-enterobacterial pathogenic species that utilize the Type III secretion system:
- Pseudomonas
- Chlamydia
Describe the structure of a Type III secretion system:
A 20-protein system, that looks like a short, hollow flagellum (needle)
What is the purpose of a Type III secretion system:
To inject a variety of specific specie-specific toxins into host cells
Often times _____ will be delivered from a bacterial cell (enteric bacteria) to a host cell via a Type III secretion system
Virulence factors
Translocated intimin receptor deliver through:
A type III secretion system
TIR
Translocated intimin receptor
What two pathogens both use a translocated intimin receptor that functions through a type III secretion system:
- Enterohemorrhagic E. coli (O157:H7)
- Enteropathogenic E. coli (EPEC)
List the modes of transmission of Escherichia coli:
- Person-to-person
- Contaminated food
- Human & animal feces (no hand washing; insect vectors)
- the 7 Fās
A cholera-like AB-exotoxin that performs ADP-ribosylation of G protein leading to increased cAMP levels resulting in loss of water & electrolytes & ultimately watery diarrhea:
Heat-labile enterotoxin āLTā
What is responsible for the condition commonly known as āTravelerās diarrheaā
Heat-labile Enterotoxin āLTā
What type of toxin is the heat-labile enterotoxin āLTā?
A cholera-like AB-exotoxin
How does the virulence factor Heat-labile enterotoxin āLTā work?
- ADP-Ribosylation of G protein
- increase in cAMP levels
- loss of water and electrolytes
= watery diarrhea
What are two virulence factors of E. coli?
- Heat-labile enterotoxin āLTā
- Shiga toxin
An AB-exotoxin cytotoxin that functions through the inactivation of 60S ribosome subunit by removal of a specific adenine base from a nucleotide of 28s rRNA that results in the stop of translation, leading to cell death & blood diarrhea:
Shiga toxin
lt
What kind of toxin is Shiga toxin?
AB-exotoxin cytotoxin
Foodborne enterotoxigenic ETEC E. coli may be responsible for ______ and specifically caused by ________
Watery diarrhea; heat-labile enterotoxin āLTā
Foodborne enterohemorrhagic EHEC E. coli O157:H7 may be responsible for ______ and specifically caused by _____
Bloody diarrhea; Shiga toxin
In addition to bloody diarrhea Shiga toxin may also be responsible for:
Hemolytic uremic syndrome resulting in kidney damage/failure
Describe how the virulence factor shiga toxin works:
- Inactivation of the 60s ribosome subunit by removal of a specific adenine base from a nucleotide of 28S rRNA
- Stop translation
- Cell death
= Bloody diarrhea
Describe the symptoms of Shigella Dysenteriae:
- Diarrhea with blood
- Intestinal cell invasion
- Apsoptosis of neutrophils to cause pus in diarrhea
What disease is responsible for the set of symptoms ādiarrhea with bloodā combined with intestinal cell invasion, apoptosis and neutrophilic resulting in pus and ultimately dysentery?
Shigella dysenteriae
What virulence factors of E. coli often have a seasonal basis to their incidence?
Shiga toxin
EHEC:
Enterohemorrhagic E. Coli (O157:H7)
Enterohemorrhagic E. coli (O157:H7) clinically appears as:
- Bloody diarrhea
- Hemorrhagic colitis
- Hemolytic uremic syndrome