Vagina and Penis Microflora

Question 1

Is the vagina usually aerobic or anerobic?

Answer 1

anaerobic

Question 2

What are some things that can increase oxygen concentration in the vagina?

Answer 2

tampin use
sexual activity
trauma

Question 3

In 80% of healthy women, vaginal microflora is dominated by what?

Answer 3

lactobacilli

Question 4

What is the morphology of lactobacilli

Answer 4

gram negative rods

facultative anerobes

Question 5

How do lactobacilli inhibit the growth of other bacteria?

Answer 5

lactobacilli make lactic acid which decreases pH

also make hydrogen peroxide and hydrosyl radicals

make bacteriocin proteins that form a fore in the membrane of pathogenic bacteria and fuck up their gradients

Question 6

How do the lactobacilli make that lactate?

Answer 6

vaginal epithelial cells have lots of glycogen and when they slough off, this glycogen becomes extracellular and converted to glucose which is used for lactate production via anerobic glycolysis

Question 7

What is that lactate probably used by?

Answer 7

probably immune cells in the vagina?

Question 8

This whole process requires what hormone?

Answer 8

estrogen

pre-pubertal girls don’t have the same type of vaginal microgflora because of this

Question 9

What transporter is required for cells to take up this lactate?

Answer 9

monocarboxylate transporters

Question 10

Monocarboxylate transporters are symporters with lactate and what?

Answer 10

H+

In other words, these MCTs raise pH by taking up H+

Question 11

What stereoisoform of lactic acid is formed by lactobacilli?

Answer 11

trick question - they can make both

Question 12

Why is this a thing we care about?

Answer 12

the MCT on human cells can only take up one version

Question 13

What additional molecule found in lactobacilli can interconvert L and D lactate?

Answer 13

lactate racemase

Question 14

Lactobacilli can make hydrogen peroxide from pyruvate via what enzyme?

Answer 14

pyruvate oxidase and glucose oxidase

Question 15

Why is this hydrogen peroxide formation probably not all that important?

Answer 15

because you need oxygen for it, and the vagina is mostly anaerobic

also, the most common lactobacilli is L. iners, which can’t produce hydrogen peroxide

also, gardnerella vaginosis doesn’t get hurt by hydrogen peroxide

Question 16

Why is this hydrogen peroxide formation probably not all that important?

Answer 16

because you need oxygen for it, and the vagina is mostly anaerobic

also, the most common lactobacilli is L. iners, which can’t produce hydrogen peroxide

also, gardnerella vaginosis doesn’t get hurt by hydrogen peroxide

Question 17

Again, how do bacteriocins kill other bacteria?

Answer 17

form a pore in the cell membrane resulting in depolarization

Question 18

About 20% of health women do not have lactobacilli dominate dmicrobial communities. What are some of the other bacteria they’ll have?

Answer 18

atopobiun
corynebacterium
anerococcus
gardnerella
staphylococcus

tend to have a pH that is slightly higher - 5.3 to 5.5

Question 19

True or false; bacterial vaginosis is not caused by a single pathogen

Answer 19

true - it’s a disruption of the normal vaginal microflora such that there is a decrease in lactobacilli and an increase in other facultative anerobe species that results in inflammation and host response that causes the symptoms

Question 20

In bacterial vaginosis, does the microflora become more varied or less varied?

Answer 20

more varied (and less lactobacilli as said before)

Question 21

What is the most abundant species in bacterial vaginosis?

Answer 21

gardnerella

but also mycoplasma, mobiluncus, and atopobium

Question 22

What are the two ways to diagnose BV?

Answer 22

by symptoms - amsel criteria

by microflora - nugent score (more of a research thing)

Question 23

What is the general treatment for BV?

Answer 23

metronidazole

boric acid for symptom relief

Question 24

How does metronidazole work?

Answer 24

in anerobes - it interferes with pyruvate oxidation such that it creates lots of oxidative stress and mucking up pyruvate metabolism so the cell doesn’t get energy

Question 25

Pelvic inflammatory disease is infection of what areas?

Answer 25

upper genital tract (compared to BV which was lower genital tract)

Question 26

What are the common PID etiologic agents?

Answer 26

neisseria gonorrheoaea
chlamydia trachomatis
haemophilus influenza
streptococcus pyogenes
mycoplasma genitalium

Question 27

What is the drug mainly geared towards Neisseria?

Answer 27

Ceftriaxone

Question 28

What is the drug mainly geared toward chlamydia?

Answer 28

doxycycline

Question 29

What is the drug mainly geared toward chlamydia?

Answer 29

doxycycline

Question 30

Toxic Shock syndrome ischaracterized by what symptoms?

Answer 30

fever
diffuse rash
hypotension
organ dysfunction

Question 31

Why did TSS decrease significantly in incidence in the 80s?

Answer 31

they started using cellulosic fibers, which are less likely than cotton fiber to harbor bacteria

Question 32

90% of TSS cases are associated with what bacteria?

Answer 32

Staphylococcus aureus

rest is strep

Question 33

How does the TSS toxin lead to this severe disease?

Answer 33

the staph aureus expresses a toxin that acts as a superantigen that will activate the T cells by binding to both the TCR and MHCII (the constant regions - not the variable region)

so all the T cells in the body get activated at the same time - you get an ummune response to everything basically

Question 34

What protein acts as the superantigen?

Answer 34

TSST-1

Question 35

WHere is TSST-1 encoded in the staph?

Answer 35

SaP1T pathogenisity island

Question 36

What are pathogenicity islands in general?

Answer 36

regions of the genomes that contaain non-essential genes - so the bacteria can live without them

often encode toxins or other proteins that enhance the virulenc of bacteria

Question 37

How is the SaPI1 pathogenicity island spread?

Answer 37

phage transduction

thus a community of staph that is in benign equilibrium with the vaginal microbiome can become pathogenic quickly if SaPI1 spreads into the community

Question 38

WHat transcription factor plays a central role in the generation and propagation of the inflammatory response?

Answer 38

NfKb

Question 39

WHat transcription factor plays a central role in the generation and propagation of the inflammatory response?

Answer 39

NfKb

Question 40

True or false: patients with S aureus sepsis often get toxic shock syndrome too.

Answer 40

false - rarely do

furthermore, patients with toxic shock syndrome rarely have positive S aureus blood cultures

Question 41

THe microflora of the penis is dominated by what bugs?

Answer 41

lactobacillus again

Question 42

Circumcision has a well documented effect on HIV transmission (aka, inhibits transmission). Why might this be in relation to microflora?

Answer 42

it might alter the mcirobial community on or in the penis to increase protection from pathogenic organisms

also removes a point of entry for the HIV virus (the inner layer of the foreskin)

Question 43

WIth circumcision you get an increase in ____ bacteria and reduction in ____ bacteria

Answer 43

increase in aerobic

reduction of anaerobic

Question 44

WHy do we think this matters increase in aerobic bacteria leads to a reduction of HIV transmission?

Answer 44

we think it reduces the inflammatin and reduces the number of CD4+/CCR5+ macropahges in the urethra (so they’re not there to be infected by the HIV)

Question 45

Epididymitis is inflammation of the epididymis - usually caused by bacterial infection. What’s the bug in prepubertal boys? Men under 35? men over 35?

Answer 45

boys - #E coli
under 35 - chlamydia and gonorrhaea
over 35 - e coli, pseudoomonas

Question 46

What are the 5 types of prostatitis syndromes?

Answer 46

Type I: Acute bacterial prostatitis

Type II: Chronic bacterial prostatitis

Type IIIA: Inflammatory chronic pelvic pain syndrome

Type IIIB: Noninflammatory chronic pelvic pain syndrome

Type IV: Asymptomatic prostatitis