Vibrio and aeromonas

  1. What is vibrio physiology and structure
    all strains have LPS consisting of lipid A endotoxin, core polysaccharide, O polysaccharide.
  2. what is significance of O polysaccharide for vibrios
    used to divide vibrio species into serogroups
  3. what temperature range can vibrios grow in
    • broad temp range
    • 14 - 40 C
  4. what is the pH range of vibrios
    • wide range
    • 6.5-9.0
  5. are vibrios susceptible to stomach acid
  6. do vibrios require salt for growth?
  7. what are the components of LPS for vibrios
    • lipid A (endotoxin)
    • core (vibrio) polysaccharide: distinct from enterobacteriacae core polysach
    • O polysaccharide: used to subdivide vibrio into serogroups
  8. V. cholerae O1 does/does not produce capsule
    does produce capsule
  9. V. vulnificus and non -O1 V. cholera produce what kind of capsule
    acid polysaccharide capsule
  10. what serogroup of v. cholera produces cholera toxin
    O1 strains of V. cholera
  11. what does cholera toxin do to patients
    • severe hypersecretion of water and electrolytes from intestinal by increasing cAMP levels
    • adheres to mucosal layer by toxin co-regulated pilus and chemotaxis proteins
    • cells that cannot adhere are unable to establish infection
  12. what are the toxins that can still cause significant diarrhea
    • accessory cholera exotoxin
    • zonula occludens toxin
  13. what are the virulence factors for V. parahaemolyticus
    • adhesins
    • thermostable direct hemolysin (TDH) AKA kanagawa hemolysin
    • Type III secretion systems
  14. describe thermostable direct hemolysin and its function
    • enterotoxin: affects intestines and digestive tract
    • induces chloride ion secretion by increasing intracellular calcium
    • causes B-hemolysis
    • AKA kanagawa hemolysin
  15. what are v. vulnificus virulence factors (4)
    • degrades lysine and stomach acid, producing alkaline by products
    • evade host immune response by inducing macrophage apoptosis
    • polysaccharide capsule
    • surface proteins mediate attachment to host cells
    • cytolytic toxin secretion leads to tissue necrosis
    • cytolysins
    • proteases
    • collagenase
  16. where do virbios grow naturally in
    • estuarine/marine environments where sea water meets fresh water
    • pathogenic vibrios grow inside chitinous shellfish and form biofilms
    • can be asymptomatic in humans
  17. how is virbio spread
    • by contaminated water and food
    • high inoculation
    • hyperinfectiity is lost after 24 hrs
    • most organism are killed by stomach acids
  18. what are polyclonal and monoclonal strains of v. cholerae
    • polyclonal: v.cholerae strains in endemic areas without epidemic disease
    • monoclonal: v. cholerae strains in epidemic waters where one highly infection
  19. what diseases are caused by V. parahaemolyticus
    • gastroentereitis: mild to cholerae like conditions. explosive watery diarrhea, from shellfish
    • wound infections: from seawater
  20. what are the diseases of v. vulnificus
    • septicemia: sudden onset of fever and chills, vomiting, diarrhea. 50% mortality rate
    • wound infection: swelling, erythema, necrosis. 20-30% mortality rate
  21. what is the source of infection for v. cholerae
    water, food
  22. what is the source of infection of v. parahaemolyticus
    shellfish, seawater
  23. what is the source of infection for v. vulnificus
    shellfish, seawater
  24. what are the virulence factors of v. cholerae
    • cholera toxin
    • toxin co-regulated pilus (TCP)
    • chemotaxis protein (cep)
    • accessory cholera enterotoxin (ace)
    • zonula occludens toxin (zot)
    • neuraminidase
  25. what is the biological effect of cholera toxin
    hypersecretion of electrolytes and water
  26. what is the biological effect of toxin co-regulated pilus (TCP)
    • surface binding site receptor for bacteriophage CTX
    • mediates bacterial adherence to intestinal mucosal cells
  27. what is the biological effect of accessory cholera enterotoxin (ace)
    increases intestinal fluid secretion
  28. what is the biological effect of chemotoxis protein (cep)
    adhesin factor
  29. what is the biological effect of neuraminidase
    modifies cell surface to increase GM, binding sites for cholera toxin
  30. what is the biological effect of kanagawa hemolysin
    enterotoxin that induces chloride ion secretion
  31. what is the biological effect of cytolysins, proteases, and collagenase
    mediates tissue destruction
  32. how is virbio diagnoses
    • immunoassays for cholera toxin or O1 and O139 LPS
    • culturing on TCBS agar or alkaline peptone enrichment broth
    • salt growth (0.5%)
  33. what is the treatment for v. cholerae
    • fluid and electrolyte replacement 
    • antibiotic therapy to reduce exotoxin production (shedding)
    • improve sanitation
    • vaccines
  34. what is the treatment of v. parahaemolyticus
    • fluid and electrolyte replacement
    • antibiotic therapy
  35. what is the treatment for v. vulnificus
  36. where is aeromonas found in
    ubiquitous in fresh and brackish water
  37. aeromonas cause what types of diseases (3)
    • water diarrhea, dysenteric diarrhea, intermittent diarrhea
    • wound infections
    • opportunistic systemic disease
  38. aeromonas are G(-/+), oxygen requirement, shape
    • G(-)
    • facultative anaerobic
    • fermentative rod
  39. how can aeromonas be distinguished from enterobacteriaceae
    (+) oxidase
  40. how is aeromonas treated
Card Set
Vibrio and aeromonas
v. cholerae and c. vulnificus