Microbiomes- Skildog

Question 1

What 3 products of lactobacilli inhibit the colonization of mucosal epithelium by other flora?

Answer 1

Lactic acid = decreases pH

Hydrogen peroxide = makes hydroxyl radicals

Bacteriocins = depolarize cell membranes of pathogenic bacteria

Question 2

Describe the production of lactic acid in the vagina…

Answer 2

• Estrogen causes proliferation of epithelium in vagina
• Increased uptake/storage of glucose
• Vaginal epithelial glycogen production
• Epithelial cells are sloughed
• Glycogen released extracellularly
• Uptake by lactobacilli
• Converted to pyruate
• Lactate dehydrogenase takes pyruvate to lactate

Question 3

Why is lactic acid production in the vagina important?

Answer 3

Lactate is a high energy substrate for immune cells

Hydrogen ion produced during glycolysis decrease the vaginal pH (3.5-4.5)

Question 4

What enzyme converts pyruvate into lactate?

Answer 4

Lactate dehydrogenase

Question 5

How do immune cells take up lactate?

Answer 5

Monocarboxcylate Transporters

Symporter: one proton and one molecule of lactate

*Only takes up L form of lactate

Question 6

What enzyme is produced by lactobacillus to interconvert L and D lactate?

Answer 6

Lactate racemase (LAR)

Question 7

What 2 enzymes do lactobacilli have that produces hydrogen peroxide?

Answer 7

Pyruvate Oxidase

Glucose Oxidase

Question 8

Does hydrogen peroxide inhibit growth of vaginal pathogens like Gardnerella?

Answer 8

Nope!!

Question 9

What is the MOA of bacteriocins?

Answer 9

For pore in target cell’s membrane, resulting in depolarization and outflow of cytoplasmic contents

Or can disrupt the cell wall, or both

Question 10

What is bacterial vaginosis?

Answer 10

Disruption of the normal vaginal microflora

NOT CAUSED BY A SINGLE PATHOGEN

Question 11

What is the most abundant species in normal women? women with bacterial vaginosis?

Answer 11

Lactobacilli is normal

BV = Gardenella

Question 12

Treatment for bacterial vaginosis?

Answer 12

Metronidazole

Question 13

MOA of metronidazole?

Answer 13

Interferes with bacteria’s fuel metabolism

Generates reactive nitrogen - damaging nuclei acids

Question 14

How does PID result in infertility or ectopic pregnancy?

Answer 14

Causes selective loss of ciliated epithelial cells in the fallopian tube

Question 15

2 most common causes of PID?

Answer 15

N. Gonorrhoeae

Chlamydia

Question 16

Treatment for PID?

Answer 16

Ceftriaxone plus doxycyclin

Question 17

Pathogenesis of Toxic Shock Syndrome?

Answer 17

TSST-1 produced by staph aureus binds TCR and MHCII outside of antigen binding site

Overwhelming release of IL-1, IL-2, INFy, and TNFa

Causes shock

Question 18

What is TSST-1 encoded on?

Answer 18

SaPI1 Pathogenicity Island

Question 19

How do pathogenicity islands spread?

Answer 19

Through phage transduction

Regions that contain non-essential genes

Encode toxins or other proteins that enhance virulence of bacteria

Question 20

What does coagulase do?

Answer 20

activates fibrin, and creates a fibrin wall that protects the bacteria

Question 21

What organisms dominates the male microbiome?

Answer 21

Lactobacillus

Question 22

What are the most common sites of viral entry in the male genitals?

Answer 22

Urethra

Inner foreskin

Question 23

How does circumcision shift the microbial communities in the male genitals?

Answer 23

Shifts towards aerobic bacteria

Question 24

Epididymitis in young and old men?

Answer 24

E. coli

Question 25

Epididymitis in men puberty to 35?

Answer 25

Chlamydia trachomatis

Neisseria gonorrheae