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HDID - Bacteriology > Vibrio & Aeromonas > Flashcards

Flashcards in Vibrio & Aeromonas Deck (16)
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1
Q

name the Three strains of Vibrio which are pathogenic to humans ?

A

V. cholerae
V. parahaemolyticus
V. vulnificus

2
Q

Describe the appearance of a Cholera patient?

A

Profuse watery diarrhea;
Rice water stools – (Rice= flecks of intestinal mucosa)

Severe Dehydration -
loss of skin turgor
sunken eyes

Vomiting

Leg cramps

hypovolemic shock

3
Q

what are the two cholera serotypes associated with cholera Epidemics?

A

O1 and O139

Virulence factors (CT and Toxin Co-Regulated Pilus) are exclusively on these two serotypes

4
Q

Epidemiology of Cholera:

  • how is it tranismitted?
  • What is its environemntal reservoir?
  • what condition leads to increased severity of disease ?
  • where does cholera colonize in humans?
A
  • Fecal/Oral transmission;
  • Low stomach acid leads to increased severity of disease

–Brackish water reservoirs

  • colonizes in the small intestine
5
Q

What are the virulence factors of Cholera? describe their mechanisms

A

1) Cholera Toxin – AB Toxin
- B binds to GMI Gangliosides
- A subunit: ADP ribosylating of G- alpha-s –> AC –> cAMP –> opening of CFTR channels + closure or Na absorption channels

Water follows = Diarrhea

2) Toxin Coregulated Pilus – Type 4 pilus critical for colonization of the small intestine. Regulated by ToxR. ToxR is upregulated in In Vivo conditions

Once a cell is infected, it stays intoxicated until is sloughed off

6
Q

Where does cholera colonize?

A

The small intestine

7
Q

Treatment and Prevention of Cholera

A

Treatment:
1) Rehydration: Replenishment of the fluids and electrolytes

2) Abx: Tetracycline (but always with rehydration therpay)

Prevention: Vaccine
- Mutated organism missing the A toxin, but still has the immunogenic B toxin

8
Q

• V. parahaemolyticus

  • what are outbreaks associated with?
  • what is the environmental reservoir ?
A

Leading bacterial cause of seafood associated gastroenteritis;

outbreaks in coastal states associated with eating sea foods (crabs, oysters, shrimp)

Reservoir: estuary environments

9
Q

• V. parahaemolyticus

- Describe the (2) disease manifestations?

A

Diarrhea: watery, self-limited diarrhea, Cramps, nausea, vomting

Wound: Some wound infections after exposure to warm seawater

10
Q

• V. parahaemolyticus

what are it’s virulence factors?

what is unique about its generation time?

A

Enterotoxin – thermal stable hemolysin.

Rapidly growing – generation time 9 minutes

11
Q

V. vulnificus

  • what are the disease manifestations?
  • who is at risk for the more severe version of the disease?
A

1) Wound infections:
occurs after exposure of wound to warm seawater (eg a patient lacerated hand while cleaning crabs)
wound infxn -> cellulitis -> bullae -> necrosis.

2) Primary Sepsis:
ingestion of raw seafood –> bacteremia –> sepsis, fever, chills, hypotension,

secondary skin lesions –> vessilces/blullae –>necrotic ulcers

for the later group, these patients usually have pre-existing or chronic disease (HIV, cirrhosis, immunosuppressed)

90% of these cases in males

-

12
Q

What are the virulence factors of V. vulnificus?

A

polysaccharide Capsule

Endotoxin

Degradative enzymes: protease, elastase; –

13
Q

treatment of V. vulnificus?

A

Aggressive treatment: debridement, amputation,

tetracycline plus ciprofloxacin or cefotaxime

Prevention is best (i.e., no raw seafood for anyone with pre-disposing condition)

14
Q

• Aeromonas
what is the most common of the pathogenic species?

where does it reside?

A

• Aeromonas hydrophila

Soil and water

15
Q

what are the disease manifestations of • Aeromonas hydrophila ?

A

Wound infections — cellulitis related to water/soil exposure

Medicinal leech exposure

Bacteremia – usually associated with hepatic/pancreatic/biliary disease/malignancy

Some implications to diarrhea

16
Q

Treatment of Aeromonas hydrophila?

what is it resistant to?

A

Skin & Soft Tissue Infections & Bacteremia:

TMP/SOM, FQ, Aminogylcosides

Resistant to Beta Lactams

Diarrhea: Rehydration