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
an increased upward spread of a BV infection leads to…
decreased host defenses by mucolytic proteases
*also provides an innoculum
Amsel criteria
nugent score
used to dx BV
amsel critera: by sxs
nugent score: microflora composition
Tx for BV
oral/intravaginal METRONIDAZOLE
BORIC ACID for sx relief
interferes w/ bacterias fuel metabolism and generates reactive nitrogen damaging nucelic acids
metronidazole
WHAT IS requires to reduce metronidazole to its active form?
pyruvate: feredoxin oxidoreductase
* only in ANAEROBIC ORGANIMS
infection/inflammation of the upper inflammatory tract
PID
(salpingitis
endometritis
abdominal pain
discharge
PID
bacteria coated epithelial and inflammatory cells observed on wet mount of discharge are indicative of…
CLUE CELLS!!
PID
MCC of PID
G/C
gram negative diplococci, non-motile, not acid fast, oxidase positive
n. gonorrhea
gram negative, obligate intracellular parasite
c. trachomatis
often accompanies G/C
H. influenza
s. pyogenes
emerging cause of PID
mycoplasma genitalium
tiny, lack a cell wall, require cholesterol in growth media
mycoplasma genitalium
out pt tx for PID
Ceftriaxone (cefoxitin)
+ doxycycline
+/- metronidazole (only for anaerobes)
Binds to bacteria’s 30S ribosome and prevents tRNA binding, preventing protein synthesis.
doxycycline
that binds penicillin binding proteins and inhibits bacterial cell wall synthesis, resulting in osmotic imbalance and death of dividing cells. It is effective against bacteria that produce b-lactamase
Ceftriaxone
fever
diffuse rash
hypotn
organ dysfunction
TSS
90% of TSS cases are associated w/
s. aureus
streptococcal TSS accounts for rest
gram positive cocci grow in grape like clusters catalase positive non-motile aerobic / facultative anaerobic
staphylococci
what is unique about s. aureus
coagulase positive
*most others are negative
what does coagulase do
coagulase>
prothrombin>
fibrin polymerization
how do APCs display ag to T cell?
MHC II
*activation requires Ag specific binding of TCR
Superantigens
bind BOTH TCR and MHCII creating an immunological synapse w/out a specific antigen>
activation of T cells regardless of specificity of their TCR
Exotoxin produced by s. aureus that leads to TSS
SaPI1>
TSST1 (superantigen)
cytokines released from activated Th1
IL-2
IFNy
cytokines released from activated mphage
IL-1
TNF
encoded on SapI1 pathogencity island
TSST-1
regions that contain NON-essential genes (bacteria can live w/out them) that encode TOXINS or PROTEINS that enhance the VIRULENCE of bacteria
pathogenicity island
how are SaPI1 pathogenicity islands spread
phage transduction
**a community of s. aureus in BENIGN equilibirum can quickly become PATHOGENIC if PI spreads
plays a central role in the genration and propagation of the inflammatory response
NFkB
relationship between s. aureus in blood and TSS
NOPE
sampling locations on penis for microbiological studies
the urethra (interior), coronal sulcus (exterior or interior), urine, prostatic secretions.
dominates penis microbiome in healthy males
lactobacillus
infection w/ an STI in a man is associated w/….
a DEPLETION in lactobacillus
reduces HIV transmission
reduces BV in partners
circumcision–> increases protection from pathogens by altering microbial community towards AEROBIC bacteria
why can an increased number of aerobic bacteria associated w/ circumcision be beneficial?
reduces inflammation
reduces number of CD4+/CCR5 mphages in urethra
inflammation of the epididymis usually cuased by bacteria
epididymitis
epididymitis in prepubertal boys
e. coli
epididymitis in men < 35
G/C
epididymitis in men >35
E. coli
Pseudomonas
pain
swelling
fever
dysuria
epididymitis
tx for epididymitis caused by e. coli
quinalone (levofloxacin)
tx for epididymitis caused by G/C
doxy+ ceftriaxone