Lecture 12- Vibrio Species Flashcards
Vibrio sp.
- nonspore-forming, gram-negative
- vibrio shaped bacterium
What are the 3 species of vibrio that are known to cause most infections?
Vibrio parahaemolyticus
Vibrio vulnificus
Vibrio cholera
The vibrio infection are most associated with what?
Seafood consumption
-vibrio in water are part of the natural microbiota of the water
Is vibrio caused by fecal contamination?
No, the fecal oral route does not apply to Vibrio
What is the serotypes of v.parahaemolyticus?
LPS (O) antigen, and capsular polysaccharide (K) antigen
What is the generation time and temperature for V.parahaemolyticus?
Generation time: 8-9min at 37C
-the ability to grow rapidly means that contaminated food becomes highly colonized if temperature abused
Symptoms of Vibrio parahaemolyticus
appear 4-30 hours after ingestion of contaminated food
- D, N, V, abd cramps, fever
- subside in 3-5 days
How many flagellum does v. parahaemolyticus have and where is it located?
single flagellum at one pole of the bacterium is required for swimming motility
-during growth in semi-solid media, flagella are produced along the lateral side of the bacterium
What is the role of MAM7 in v. parahaemolyticus?
Multivalent adhesion PRO that binds to fibronectin and phosphatidic acid which is required for the initial attachment to host cells
What are the haemolysis factors that v. parahaemolyticus have?
-Fe transporters are internalized by diff membrane receptors on the outer membrane of the bacteria and transported to the cytoplasm by different ABC complexes.
What are the 3 toxins produced by v. parahaemolyticus?
- thermoliable haemolysin (tlh)
- thermostable direct haemolysin (tdh)
- thermostable direct-realted haemolysin (trh)
How are thermostable direct haemolysin (TDH) and thermoliable haemolysin (TLH) secreted?
secreted from the bacteria and form tetrameric pore complexes in the host membrane
the pores allow ions to flow freely across the host membrane which leads to hemolysis or cytotoxicity
What functions do T3SS1 effectors have?
VopQ, VopR, VopS, and VPA0450 are effectors that are translocated into the host cells to cause cytoxicity in different cell types such as macrophages and HeLa cells
Where is T3SS1 found?
in all V.parahaemolyticus isolates, even non-pathogenic isolates, indicating an imp. role in the environment
What function do T3SS2 effectors have?
Vop A, VopC, VopL, VopT are translocated into host cells to cause cytotoxicity of colon epithelial cells or enterotoxicity within the host
Where is T3SS2 found?
mainly in clinical isolates indicating that it is more tightly ties to a pathogenic lifestyle
What are the 4 effector of T3SS1?
VopQ, VopR, VopS, and VPA0450
What are the 4 effectors of T3SS2?
VopA, VopC, VopL, and VopT
Which species has the most serious infection and is responsible for 95% of seafood related deaths in North America?
V. vulnificus
What are the 3 biotypes of v. vulnificus?
- Causes diseases in humans
- causes disease in eels, rarely in humans
- hybrid of type 1 and 2, found only in Israel
What is the primary syndrome of v. vulnificus?
Primary septicemia caused by consumption raw or undercooked seafood
What is the second syndrome of v. vulnificus?
necrotizing wound infection which results from an open wound being exposed to warm seawater, or contaminated seafood, with high concentration of v. vulnificus
Fatality rate of primary septicemia from v. vulnificus?
60% –> high usually from the consumption of oysters
Symptoms of v. vulnificus?
appear 7 hours to several days after exposure
-fever, chills, N, hypotension
virulence factor v. vulnificus k antigen
polysaccharide capsule
- if cells loose the K-antigen they lose virulence
- the role in virulence is not understood
virulence factor v.vulnificus LPS (O antigen)
the high fever, systemic infection, and shock are consistent with LPS induced endotoxic shock
virulence factor v.vulnificus vvhA?
a heat stable haemolysin/cytotoxin that is unique to V. vulnificus and likely plays a role in virulence
Where was the cholera outbreak in 2010?
Haiti where the mortality rate was the highest
Yemen where the people with cholera is high but death is lower than in Haiti
What is the serotyping of v.cholerae based on?
LPS (O) antigen
what are the two type of v. cholerae that cause epidemic and pandemics?
O1 and O139
What toxin do the two v. cholerae strain produce?
Cholera toxin (CTX)
What does the cholerae toxin do (CTX)?
disrupts the ion transport, this leads to severe diarrhea
- carried on a phage , only v. cholerae which are infected with this phage are able to cause illness in humans
- binds to ganglioside receptors on the surface of intestinal epithelium cells
- internalized by endocytosis and triggers the production of cAMP
does v. cholerae have a VBNC state?
Yes, where cells are reduced in size and become ovoid
What factors does v. cholerae use to colonize the small intestine?
adherence factors
cAMP is triggered by cholera toxin but what does it do after that?
activates specific ion channels within the cell membrane causing an efflux on ions from the cell
- the build up of ions in the intestinal lumen draws water from cells and tissues via osmosis causing acute diarrhea and dehydration
which species is known to undergo rapid horizontal gene transfer and why?
V. parahaemolytics because the two genes (K and O antigen) are in two discrete clusters which undergo horizontal gene transger
What needs to happen for v. cholerae to be infected?
needs to be infected with a phage to be virulent
- climate change increases the probability
can T3SS be transferred from v. parahaemolyticus to v. cholerae?
yes, when this happens it makes v. cholerae pathogenic to humans
What are some prevention of vibrio infections?
- seafood should always be frozen, refrigerated, or stored in ice, eaten fresh
- cooking very effective at eliminating vibrios
- irradiation and high hydrostatic pressure
- dried spices, herbal oils, tomato sauce, lemon juice
Does depuration (filter feeding bivalves are purified by pumping through clean water) remove Vibrio?
no but does remove salmonella and e.coli
which species of vibrios has the highest mortality rate?
V. vulnificus
