Microbiome App

Question 1

What does microbiome mean?

Answer 1

The collective genome of symbionts

Question 2

What is normal biota?

Answer 2

Microbial pathogens found on and in us

Question 3

What is the first line of defense?

Answer 3

Normal biota

Question 4

Why do we use 16S rDNA?

Answer 4

To identify previously unknown bacteria
To answer these questions:
How stable an individual’s microbiota are? Do all humans have a core microbiome? What effects genetic diversity of the microbiome?

Question 5

What are the most common mechanisms of bacterial interference?

Answer 5

Harmless bacteria displacing pathogenic bacteria; Fecal microbiota transplant used to restore missing bacteroidetes and firmicutes

Question 6

What can happen is resident microbiota are disturbed?

Answer 6

Transient microbiota may take over and cause disease

Question 7

What oral bacteria may cause endocarditis after tooth extraction?

Answer 7

Streptococci of the viridans group (alpha-hemolytic strep other than S. pneumoniae)

Question 8

Early dental plaque:

Answer 8

Gram positive colonizers such as Streptococcus sanguis; specific ionic and hydrophobic interactions as well as lectin-like surface structures adhere to the pellicle

Question 9

Late dental plaque:

Answer 9

Gram negative anaerobes; make high molecular weight polyglycans

Question 10

What is the role of sucrose in dental caries?

Answer 10

Sucrose is the substrate S. mutans uses and produces acid along with extracellular polyglycans and levans by transferase enzymes

Question 11

What is the most significant bacteria in dental caries?

Answer 11

S. mutans

Question 12

What is responsible for damage to the periodontium?

Answer 12

Bio-film induced chronic inflammatory disease (host response is responsible)

Question 13

What are the strategies to prevent dental caries and periodontitis?

Answer 13

Removal of calcified deposits
Limited sucrose intake
Good nutrition with adequate protein intake
Reduction of acid production by decreasing carb intake

Question 14

What is the quantity of bacteria in the stomach vs the colon like?

Answer 14

Stomach: few due to low pH
Colon: gradually increasing due to alkalinity

Question 15

What is the type of bacteria in the stomach and colon respectively?

Answer 15

Stomach: H. pylori
Colon: anaerobes

Question 16

What are the major functions of intestinal microbiota in defense?

Answer 16

Defense: displaces potential pathogens indirectly by competing for nutrients and receptors or antimicrobial factors
Induce secretions of IgA and develop intestinal humoral immunity and modulate T cell response and cytokine profiles

Question 17

Major functions of intestinal microbiota in metabolism:

Answer 17

Contribute AA to host
Produce short-chain FA to control intestinal epithelial cell differentiation
Synthesize vitamin K, biotin, folate and ion absorption
Aid in fermentation and nondigestible dietary residues
Fat gut deposit leading to obesity

Question 18

Mechanisms by which methanogens increase ATP production in bacteria:

Answer 18

Reduce small organic compounds into methane in the presence of H2; removal of excess H2 prevents the inhibition of bacterial NADH dehydrogenase

Question 19

Rationale of doing a FMT in C. difficile infection?

Answer 19

Displace harmful bacteria

Restore colonic microbiota to natural state by replacing bacteroidetes and firmicutes

Question 20

How can oral administration of insoluble antibiotics affect gut flora during and after treatment?

Answer 20

Result in self-limiting diarrhea or life-threatening pseudomembranous colitis
Intentional suppression of fecal flora is done preoperatively

Question 21

What insoluble antibiotics are given for aerobic bacteria?

Answer 21

Neomyocin + erythromycin

Question 22

What insoluble antibiotics are given for anaerobic bacteria?

Answer 22

Metronidazole

Question 23

What species cause peritoneal abscesses in cases of colonic perforation?

Answer 23

Bacteroides fragilis (penicillin resistant)
Clostridia
Peptostreptococci

Question 24

What role do microbiota and host immunity play in inflammatory bowel diseases?

Answer 24

Associated with loss of immune tolerance to bacterial antigens
Leads to intense inflammation caused by an exuberant immune response

Question 25

Blockage of the pylorus causes what?

Answer 25

Gram positive cocci and bacilli