Vibrio and Aeromonas Flashcards
What is the clinical presentation of O1 & O139 Vibrio cholerae?
Watery diarrhea (rice water stool)
Rapid onset with extreme dehydration
Decreased blood pressure
Poor skin turgor (pinch, stays raised due to dehydration)
What is the treatment for cholera?
Rehydration therapy ESSENTIAL
Can use tetracycline to shorten duration of diarrhea
What is the difference between O1&O139 V. cholera v. non-O1 &O1-39 V. cholera?
O1 &O139 are the only serogroups that produce cholera toxin and contain the pathogenicity island
Hence, Non O1& O139 do not usually cause disease
Where is non O1 & O139 V. cholera typically found?
Brackish water, seafood
Does V. cholera affect small of large bowel?
Small bowel
How does hyperchlorhydia affect susceptibility to Cholera?
Increases susceptibility and severity
Less stomach acidity so lose that barrier to infection
What is the pathogenesis of cholera toxin?
V. cholera in lumen of bowel releases cholera toxin
B subunit binds GM1 gangliosides, gets internalized
A subunit ADP-ribosylates G protein, which permanently turns on adenylate cyclase (AC)
AC -> increased cAMP -> blocked Na absorption, Cl efflux -> water follows
What determines when patient will recover?
Once intestinal cells with the permanently turned on adenylate cyclase have been sloughed off
What are the major virulence factors of V. cholera?
Cholera toxin
TCP (toxin-coregulated pilus)
What regulates the virulence factors of V. cholera?
ToxR, activates virulence factors depending on environment
Where is Vibrio parahaemolyticus commonly found?
Seafood, leading cause of seafood-associated gastroenteritis
What is the virulence factor of V. parahaemolyticus?
Enterotoxin TDH
Where is Vibrio vulnificus found?
Seafood, leading cause of seafood-related deaths
What are the two clinical syndromes caused by V. vulnificus?
Wound infection - seen in otherwise healthy people
Primary sepsis - seen in compromised hosts with pre-existing heptic disease
What is the clinical presentation of wound infection due to V. vulnificus?
From wound exposed to seawater
Cellulitis, sometimes with vesicles or bullae, followed by necrosis
Sometimes progress to sepsis or death in those with underlying disease
