Vibrio Flashcards
How many species of vibrio cause infection in humans
12
What 3 species of vibrio are most associated with illness in humans
V. parahaemolyticus, V. vulnificus, V. cholera
Most vibrio isolated in the each of the possibly pathogenic species are….
non-pathogenic
Where is vibrio predominantly found
Estuarine waters
What time of year do vibrio numbers in water spike
Summer
What vibrio species are NOT part of the natural microbiota of the water
V. cholerae O1 or O139
What temperature must a water supply go above for it be “vibrio season”
17C
How is V. parahaemolyticus serotypes
By its O and K antigen
What are vibrio infections linked to
Consumption of raw or undercooked seafood
What is a key feature of V. parahaemolyticus
It has a rapid generation time (8-9 minutes at 37C)
What protein in V. parahaemolyticus is needed for initial attachment to the host
MAM7 (binds fibronectin and phosphatidic acid)
What are the 3 siderophores of V. parahaemolyticus
Vibrioferrin, ferrichrome and aerobactin (also uses heme, all used to scavenge iron)
What are the 3 hemolytic toxins produced by V. parahaemolyticus
Thermoliable hemolysin (tlh)
Thermostable direct hemolysin (tdh)
Thermostable direct-related haemolysin (trh)
What is the action of TDH and TRH
They form a tetrameric pore complex in the host membrane, leads to hemolysis of cytotoxicity
What are the effectors of the V. para T3SS1
VopQ, VopR, VopS and VPA0450
What are the effectors of V. para T3SS2
VopA, VopC, VopL and VopT
What T3SS of V. para is more associated with the pathogenic lifestyle
T3SS2
What do the effectors of T3SS2 in V. para cause?
Cytotoxicity of colon epithelial cells, or enterotoxicity within the host
How is V. vulnificus divided
Into 3 biotypes based on biochemistry
What are the 3 biotypes of V. vulnificus
- Causes disease in humans
- Causes disease in eels, rarely humans
- A hybrid of 1 and 2 (only found in isreal)
What are the 2 V. vulnificus syndromes
Primary septicemia (from eating raw seafood) or necrotizing wound infection (open wound being exposed)
V. vulnificus is only isolated from…
Warm waters
What/when do V. vulnificus symptoms appear
7 hours, fever, chills, nausea and hypotension
What are 3 virulence factors of V. vulnificus
The K antigen (capsule)
O antigen (LPS)
vvha
What symptoms of V. vulnificus infection are consistent with LPS induced endotoxic shock
High fever, systemic infection and shock
What is vvhA in V. vulnificus
A heat-stable haemolysin/cytotoxin that is unique to V. vulnificus
What is the main challenge in Vibrio outbreak source tracing
The most common PFGE patterns tend to drift over the course of an outbreak, indicating that multiple concurrent outbreaks may be occurring (also challenges single source introduction hypothesis)
What is the serotyping of V. cholerae based on
the LPS (O) antigen
What are the two strains of V. cholerae known to cause epidemics and pandemics
O1 and O139
What do V. cholera O1 and O139 produce
The cholera toxin (ctx)
What state do V. cholerae exist in
VBNC
Where does V. cholerae attach
The small intestine (using adherence factors)
What is the action of the ctx toxin
It disrupts ion transport in the small intestine and causes diarrhea
How does ctx cause acute diarrhea
Binds ganglioside receptors, internalized, produces cAMP, cAMP activates ion channels, efflux of ions out, build up of ions draws water out of the cells, causes diarrhea and dehydration
When does V. cholerae become competent
When it is grown in chitin (readily takes up DNA from the environment)
What genes readily move between V. para genomes
tdh and trh
Ways to prevent vibrio infection
Keep cold, cooking, irradiation, high hydrostatic pressure
What prevention method does not work on vibrio
Depuration (filter-feeding bivalves are purified by pumping through clean water)
