Bacterial GI Pathogens

Question 1

Are the e.colis that cause diarrhea the same ones that cause UTIs?

Answer 1

NO, we pathogen type e. colis

Question 2

What are the 3 types of e.coli pathogen types?

Answer 2

• Commensal/symbiotic : no disease
• Extraintestinal disease (UTI, pneumonia, mastitis)
• Intestinal disease (diarrhea, vomiting)

Question 3

What are the two major groups of intestinal e. coli pathogenecity?

Answer 3

Non-Toxigenic
Toxigenic

Question 4

What are the Non-toxigenic E. coli pathotypes?

Answer 4

Enteropathogenic (EPEC)
Adherent and Invasive (AIEC)

Question 5

What are the two types of Toxigenic E.coli pathotypes?

Answer 5

Enterotoxigenic (ETEC)
Shiga Toxin (STEC)

Question 6

What species do EPECs infect?

Answer 6

All species including humans

Question 7

What is the characteristic of EPECs?

Answer 7

Attaching and effacing lesions formed; EPEC attaches via intimin and injects effector proteins –> conformational change and decrease in surface area causing malabsorption

Question 8

What is the mechanism of action of AIEC?

Answer 8

Invade enterocytes and survives within vacuoles of enterocytes

Question 9

What are some characteristic pathologies of AIEC?

Answer 9

proliferative lesions associated with chronic inflammation

Question 10

How do you diagnose AIEC?

Answer 10

Biopsy + FISH

Question 11

What causes boxer dog colitis?

Answer 11

AIEC

Question 12

What is the major cause of primarily neonatal diarreah in calves, lambs, and piglets?

Answer 12

ETEC

Question 13

Why type of diarrhea do you see with ETEC infection?

Answer 13

Watery and non-bloody

Question 14

what ate the 2 major toxins produced by ETEC

Answer 14

Heat liabile (HT)
Heat Stable (HS)

Question 15

How does the Heat Labile toxin cause diarrhea?

Answer 15

Activates adenylate cyclase –> intracellular cAMP increased –> Prevent Na absorption & increase Cl excretion –> water follows salt

Question 16

How does the Heat Stable Toxin cause diarrhea?

Answer 16

Activates guanylate cyclase

Question 17

How do Shiga toxins work?

Answer 17

They bind to Gb3 (receptor on endothelial cells –> endocytosis –> removes and adenine from ribosome and halts protein synthesis –> host cell death

Question 18

What type of diarrhea do Shiga toxins cause?

Answer 18

Bloody diarrhea

Question 19

What is E. coli enterotoxemia?

Answer 19

Pig edema disease; causes edema, lateral recumbency, padding

Question 20

Enterohemorrhagic E. coli (EHEC)

Answer 20

O157:H7 is the ptototype EHEC

Question 21

What does EHEC do?

Answer 21

causes disease in humans… usually associated with fast food

Question 22

What type of bacteria is Salmonella?

Answer 22

Aerobic (facultative anaerobic), gram negative bacilli, lactose non-fermenter on MacConkey agar

Question 23

Salmonella is acid sensitive.. What does that mean?

Answer 23

Requires a very high infectious dose

Question 24

What salmonella is the subspecies associated with mammalian or birds?

Answer 24

Salmonella entericay subsp. enterica

Question 25

What salmonella is the subspecies associated with reptiles?

Answer 25

Salmonella enterica subsp. arizonae

Question 26

What is the salmonella associated with typhoid fever in humans?

Answer 26

Salmonella enterica serovar Typhimurium

Question 27

How is salmonella spread?

Answer 27

Fecal oral transmission

Question 28

True/False: Salmonella is the leading bacterial foodborne pathogen

Answer 28

True

Question 29

What is the most important risk factor in pets for salmonella?

Answer 29

Raw food diets

Question 30

Have there ever been salmonella outbreaks in people from feeding raw food diets?

Answer 30

Yes

Question 31

Can animals colonize salmonella and have no disease present?

Answer 31

Yes

Question 32

What are the clinical signs of salmonella for NON host specialist strains?

Answer 32

-Clinical signs are variable - Acute episodes of fever, malasia, anorexia, vomiting, abdominal pain, diarrhea

Question 33

How to diagnose salmonella

Answer 33

isolation of bacterial from feces; let lab know you are particularly interested in salmonella and they will culture on enrichment broth in specialized media/PCR run on broth

Question 34

Does a single negative test of salmonella rule out salmonella?

Answer 34

No, because it is shed intermittently

Question 35

Can salmonella be harbored asymptomatically?

Answer 35

Yes

Question 36

What is the treatment for salmonellosis with d+ only?

Answer 36

Supportive therapy; drug treatment an induce resistant strains and prolongs convalescent shedding... NO ABX

Question 37

What is treatment for systemic disease of salmonellosis?

Answer 37

TMs, chloramphenicol, 3rd gen cephalo

Question 38

What does campylobacter look like on a gram stain?

Answer 38

seagull

Question 39

What is this

Answer 39

campy

Question 40

What animals are the reservoir for campylobacter?

Answer 40

Birds; campy is commensal in the intestines of birds

Question 41

How is Campylobacter transmitted?

Answer 41

VERY easily; fecal oral route, very low infectious dose as low as 500 cells

Question 42

What are the two main species of Campylobacter?

Answer 42

C. jejuni -- chicken, cattle, dogs C. coli -- pigs/dogs

Question 43

What are the clinical signs of campylobacter?

Answer 43

may be asymptomatic, acute diarrhea, can be chronic diarrhea

Question 44

What animals are most susceptible to campy infection?

Answer 44

Young puppies

Question 45

How do we treat Campylobacter

Answer 45

Tylosin, erythromycin, azithromycin