1.05 & 1.06 GI Microbio

Question 1

What are the two major bacterial phyla dominant in human gut microbiota?

Answer 1

Firmicutes and bacteroides

Question 2

Major gram negative residents of the GI tract?

Answer 2

Bacteroidetes

Question 3

Major gram positive residents of the GI tract?

Answer 3

Firmicutes

Question 4

Lactobacillus and clostridium belong to what major bacterial group?

Answer 4

Firmicutes

Question 5

What happens to the diversity of gut microbiota as you move down the GI tract ?

Answer 5

It gets more diverse

Question 6

The gut microbiome can protect from invaders by sometimes producing what antibiotics?

Answer 6

Colicin and bacteriocin

Question 7

How do resident gut microbes held in digestion?

Answer 7

Ferment non-digestible polysaccrides, produce SCFA, affect lipid storage, absorption of vitamins (K)

Question 8

What is the role of the gut micorbome and the immune system?

Answer 8

Initial residents “train” future residents via expression of TLR influencing oral tolerance and even a role in allergies

Question 9

What two bacterial groups are implicated in serious infections following perforations?

Answer 9

Bacteroides and Peptostreptococcus

Question 10

Before delivery, the vagina becomes enriched with what bacterial species that pass onto neonates?

Answer 10

Lactobacillus

Question 11

At what age does the gut microbiome stabilize once influenced by diet, environments and genetics?

Answer 11

3

Question 12

What can disrupt immune system development and is associated with higher rates of asthma, obesity, diabetes?

Answer 12

Caesarean delivery and not breastfeeding (maternal antibiotic overuse)

Question 13

Why is breast milk beneficial?

Answer 13

Molecules that mother can metabolize for them ,SCFA promote satiety, lipid/sugar metabolism produces better health

Question 14

An adult like microbiome in an infant is associated with?

Answer 14

Childhood obesity

Question 15

What neurological disorders is the microbiome implicated in?

Answer 15

Autism, depression, MS

Question 16

Gram positive rod, endospores

Answer 16

Clostridium difficile

Question 17

Most common nosocomial cause of diarrhea in the US?

Answer 17

C. Difficile

Question 18

Causative agent of pseudomembranous colitis?

Answer 18

C. Diff

Question 19

C diff requires what enterotoxin necessary for its pathogenesis targeting epithelial cells?

Answer 19

TcdA + TcdB
(A-B Toxin)

Question 20

What will you see in a colonoscopy of patients with pseudomembranous colitis?

Answer 20

Raised yellow plaques and coalescing pseudomembranes

Question 21

What is an extremely effective treatment for persistent diarrhea due to a C diff infection (and the protocol for multiple recurrences)?

Answer 21

Fecal microbiota transplant

Question 22

What is the go to diagnostic detection of for C diff infection?

Answer 22

ELISA or Westernblot of diarrhea (although PCR more Sn)

Question 23

Typical antibiotic treatment for c diff?

Answer 23

Metronidazole or Vanc

Question 24

Gram negative bacillus “spiral” shaped motile

Answer 24

H. Pylori

Question 25

What are the H pylori virulence factors?

Answer 25

Mucinase (penetrates mucus layer), Urease (ammonia cloud), CagA (pathogenicity)*

Question 26

H pylori can cause gastric inflammation that can lead to what pathologies?

Answer 26

Chronic gastritis, duodenal stomach ulcers, stomach cancer

Question 27

What is the potential downside of treating an H pylori infection?

Answer 27

Increased risk of GERD and asthma

Question 28

What is unique about H pylori that explains its route of transmission?

Answer 28

Humans are the only reservoir so fecal-oral or oral-oral transmission

Question 29

What is interesting about the age of the patient when first colonized by h pylori?

Answer 29

The older someone is when first colonized the greater the likelihood of ulcers

Question 30

What H pylori virulence factor is associated with gastric inflammation and gastric cancer?

Answer 30

CagA

Question 31

What does CagA do?

Answer 31

Interacts with MAPK cascade when phosphorylated modifying the host cell shape and cell cycle

Question 32

What happens to the gastrin production in person colonized by H pylori?

Answer 32

Increased production to increase acidity ( decreased pH)

Question 33

Where does H pylori grow?

Answer 33

Mucosal layer
(breaks down tight junction and lose epithelial cells that can lead to inflammation and ulceration)

Question 34

What is the most significant contributed to non-drug cases of gastritis, gastric ulcers, and idiopathic duodenal ulceration?

Answer 34

H pylori

Question 35

H pylori colonized individuals less likely to have… (note more studies needed)

Answer 35

GERD, esophageal Carcinoma, Barrett’s esophagus, less diarrhea, asthma

Question 36

What is the quickest and most common way to diagnose an H pylori colonization?

Answer 36

Urea breath test

Question 37

Treatment for asymptomatic patient who test positive for H pylori?

Answer 37

None

Question 38

Treatment for asymptomatic patient with H pylori but FH of gastric cancer?

Answer 38

Treat!
Combo antibiotic (amoxicillin and clarithromycin) + PPI

Question 39

What is the difference a probiotic and a prebiotic ?

Answer 39

Pro = live organism
Pre = non-digestable oligosaccharide

Question 40

Concerns about probiotics?

Answer 40

Not regulated, no manufacturing standards, not required to show efficacy

Question 41

What is a synbiotic?

Answer 41

Prebiotic and probiotic combo

Question 42

Current research synbiotic trial resrecah is promising as it has found that it may reduce risks of:

Answer 42

Lower Serious infections (sepsis), lower respiratory tract infections