Toxin-producing bacterial pathogens

Question 1

what are the 3 mechanisms that pathogens can cause infection

Answer 1

invasive
toxin-producing
hybrids of the two above

Question 2

what is the most common toxin producing pathogen species

Answer 2

Vibrio

Question 3

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

Answer 3

vibrio cholerae

Question 4

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

Answer 4

A new strain of vibrio cholera that was pandemic

-mutated the O1 antigen, new LPS serotype, encapsulated

Question 5

what are the virulence factors of vibrio cholerae

Answer 5

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

Question 6

how does the phage encoded cholera toxin affect hosts

Answer 6

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

Question 7

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

Answer 7

Vibrio and ETEC (enterotoxigenic e-coli)

Question 8

what is the main pathogen that causes traveler’s diarhea

Answer 8

ETEC (enterotoxigenic ecoli)

Question 9

what 2 toxins does ETEC produce that causes travelers diarhea

Answer 9

Heat-labile toxin (LT)

Heat-stable toxin (ST)

Question 10

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

Answer 10

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

Question 11

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

Answer 11

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

Question 12

what animal is vibrio cholerae found in

Answer 12

seawater shellfish

Question 13

how do you treat secretory diarhea

Answer 13

• ORAL rehydration
• *CANT DO IV **
• antibiotics

Question 14

what two pathogens are know as “hybrid” misfits

Answer 14

EPEC (enteropathogeninc E-coli)

EHEC (Enterohemorrhagic E-coli)

Question 15

how do EPEC and EHEC ahere to GI tissue

Answer 15

Intimate Adherance

Question 16

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

Answer 16

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

Question 17

how does hybrid misfit EPEC cause diarhea

Answer 17

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

Question 18

how does hybrid misfit EHEC cause diarhea

Answer 18

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

Question 19

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

Answer 19

EHEC or enterohemmorhagic E-coli

Question 20

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

Answer 20

EHEC (enterohemorrhagic E-coli)

-cattle

Question 21

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

Answer 21

Shiga-like toxin which attacks vessels causing blood in shit

Question 22

what is the best way to diagnose EHEC

Answer 22

blood in shit

Question 23

what do you NOT treat EHEC with

Answer 23

antibiotics