Toxin-producing bacterial pathogens Flashcards

1
Q

what are the 3 mechanisms that pathogens can cause infection

A

invasive
toxin-producing
hybrids of the two above

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2
Q

what is the most common toxin producing pathogen species

A

Vibrio

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3
Q

of the 4 subspecies of Vibrio, what toxin producing pathogen causes the most severe disease

A

vibrio cholerae

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4
Q

what is the El tor strain, and what made it different from the previous strains

A

A new strain of vibrio cholera that was pandemic

-mutated the O1 antigen, new LPS serotype, encapsulated

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5
Q

what are the virulence factors of vibrio cholerae

A

flagella, pili to adhere and pili is phage encoded, meaning once the pili is expressed, the cholera toxin is phage encoded

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6
Q

how does the phage encoded cholera toxin affect hosts

A
  • toxin binds to receptor activating G protein
  • activates adenylate cyclase
  • constant increase cAMP which stops adsorbtion of Na
  • excrete Cl and get watery diarhea
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7
Q

what are the 2 pathogens that cause secretory diarhea (watery stool)

A

Vibrio and ETEC (enterotoxigenic e-coli)

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8
Q

what is the main pathogen that causes traveler’s diarhea

A

ETEC (enterotoxigenic ecoli)

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9
Q

what 2 toxins does ETEC produce that causes travelers diarhea

A

Heat-labile toxin (LT)

Heat-stable toxin (ST)

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10
Q

What is the difference b/w heat-labile toxin (LT) and heat-stable toxin (ST)

A

LT - works exactly like vibrio in that it activates adenylate cyclase resulting in secretory diarhea
ST - activates guanylate cyclase which induces cGMP causing epithelial cells to stop adsorbing Na resulting in watery stool

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11
Q

What are the steps to identifying which pathogen is causing secretory diarhea ?

A

Step 1 - rule out Vibrio cholerea
2 - inoculate plates with shit samples then
3 - grow

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12
Q

what animal is vibrio cholerae found in

A

seawater shellfish

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13
Q

how do you treat secretory diarhea

A
  • ORAL rehydration
  • *CANT DO IV **
  • antibiotics
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14
Q

what two pathogens are know as “hybrid” misfits

A

EPEC (enteropathogeninc E-coli)

EHEC (Enterohemorrhagic E-coli)

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15
Q

how do EPEC and EHEC ahere to GI tissue

A

Intimate Adherance

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16
Q

what is intimate adherance and what pathogens use this to adhere to GI tissue

A

EPEC and EHEC use this
Stage 1 - use pili to adhere
Stage 2 - pathogen injects Tir (own protein) into host
Stage 3 - Tir binds to host’s protein intimin forming pedastool like lesion

17
Q

how does hybrid misfit EPEC cause diarhea

A
  • NO toxin*
  • colonization causes (1) malabsorbtion in microvilli and (2) disruption of tight junctions from structural change when forming pedastools
18
Q

how does hybrid misfit EHEC cause diarhea

A

Just like EPEC with malabsorbtion and disruption of tight junction BUT
has Shiga-like toxin also

19
Q

what pathogen produces a toxin that can lead to hemolytic uremic syndrome ?

A

EHEC or enterohemmorhagic E-coli

20
Q

what is the most common type of E-coli and what is its primary resovoir

A

EHEC (enterohemorrhagic E-coli)

-cattle

21
Q

what type of toxin does hybrid misfit EHEC produce, and what does it cause

A

Shiga-like toxin which attacks vessels causing blood in shit

22
Q

what is the best way to diagnose EHEC

A

blood in shit

23
Q

what do you NOT treat EHEC with

A

antibiotics