Skildum: Microbiology of the Penis and Vagina Flashcards
what can cause oxygen concentrations to increase in the normally AEROBIC vagina
tampon use
sexual activity
damage
dominant microorganisms in the vagina
lactobacilli
gram positive rods
facultative anaerobes that produce LACTIC ACID and HYDROGEN PEROXIDE and BACTERIOCINS
Lactobacilli
lactic acid
decreases pH
hydrogen peroxide
hydroxyl radicals
bacteriocins
proteins that depolarize pathogenic bacteria
what does the vaingal microbial community depend on
estrogen
how is extracellular glucose produced in the vagina?
ovaries> 17 b estradiol> vaginal epithelial expansion> vaginal epithelial glycogen production> epithelial cell sloughing> extracellular glycogen
MC lactobacilli
iners
gasseri
cripsatus
jensenii
how is extracellular glucose used by L iners to decrease vaginal pH?
Glucose is converted to pyrufvate and 2H
2 H are responsible for decreasing vaginal pH to 3.5-4.5
what is lactate a substrate for?
immune cells?
act as symporters and transport one proton w/ each molecule of lactate
MCTs
what happens when cells take up lactate?
they increase extracellular pH
difference between L and D lactate
Lactobacillus can make both types
L can be taken up by HOST (immune) cell through MCTs and used to generate ATP
D is NOT transported into host cells
*require 2 different lactate dehydrogenases to syntehsize
lactate racemase (LAR)
enzyme expressed by lactobacillus that is used to interconvert L and D lactate
how do lactobacilli make hydrogen peroxide from pyruvate?
PO
or glucose oxidase
what is the must abundant bacteria in healthy women and what does this say about hydrogen peroxide?
L. iners
does NOT produce hydrogen peroxide
does hydrogen peroxide inhibit the growth of vaginal pathogens, like gardnerella vaginosis?
No
proteins that are produced by bacteria and are lethal to other bacteria
bacteriocins
form a PORE in the target cell’s membrane>
depolarization and outflow of cytoplasmic contents
bacteriocins
what percent of health women do NOT have lactobacilli dominated microbial communities?
20%
characteristics of vaginal flora in healthy women who do NOT have lactobacilli dominated microbial communities
higher pH 5.3-5.5 facultative or strict anaerobes atopobium cornyebacterium anaerococcus gardnerella
s. aureus is present in what percent of healthy women
5-10%
disruptions in vaginal microbiome lead to…
bacterial vaginosis
PID
TSS
Bacterial vaginosis
NOT caused by SINGLE pathogen
disruption of NORMAL vaginal microflora
bacteria most abundant in pts w/ BV
gardneralla
what happens to lactobacilli in BV
replaced w/ anaerobic microflora
increased concentrations of the following are associated w/…..
Gardnerella vaginalis (gram variable, facultative anaerobic bacilli)
Mycoplasma hominis (tiny, lack a cell wall, require cholesterol in growth media)
Mobiluncus sp. (gram negative, anaerobic, motile curved rod)
Atopobium vaginae (gram positive, anaerobic, elliptical cocci or rod shaped)
BV