Skildum Flashcards
What is the environment of the vagina normally?
Anaerobic
In 80% of healthy women, what microorganism dominates the vaginal flora?
Lactobacilli
What is the gram staining and morphology of lactobacilli?
Gram positive rods; facultative anaerobes
What are the products of lactobacilli?
Lactic acid (decreases pH), hydrogen peroxide, bacteriocins
What organism produces lactocin 160?
L rhamnosus
The vaginal microbial community depends on what hormone?
Estrogen
How is lactate transported into cells?
MCTs
What sterioisomer of lactate is taken up by MCTs?
L-lactate
What is transported with lactate through the MCT?
H+
What is the function of lactate racemase?
Interconverts L and D lactate
What is the function of the enzyme pyruvate oxidase in lactobacilli?
Makes H2O2 from pyruvate; detoxifies of O2; helps maintain anaerobic environment
What is produced by the enzyme glucose oxidase in lactobacilli?
Takes glucose and makes D-gluconolactone; a by product from this reaction is H2O2 (again another detoxification process)
What enzymes are used by lactobacilli for detoxification of O2?
Pyruvate oxidase and glucose oxidase
What is the most abundant bacteria in healthy women?
L. Iners
What is the function of bacteriocins produced by lactobacilli?
For pores in target cell membranes
What bacteroicin disrupts the cell wall in gram positive bacteria?
Lysostaphin
What bacteriocin forms pores in cell membrane and disrupts the peptidoglycan transfer to the cell wall?
Nisin (class I)
In 20% of healthy women, lactobacilli are not present. What bacteria are predominant in these women? What is different about their vagina?
Atopobium, corynebacterium, anaerococcus, gardnerella; pH is slightly higher 5.3-5.5
What organism is responsible for bacterial vaginosis?
Gardnerella vaginalis
Bacterial vaginosis is associated with increasing concentration of what organisms?
Gardnerella vaginalis, mycoplasma hominis, mobiluncus sp. atopobium vaginae
What is Amsel criteria?
Used to diagnose BV; 3/4 = BV
What are the criteria of Amsel criteria?
Increased homogenous thin vaginal discharge; pH of the secretion greater than 4.5; amine odor when KOH is added; presence of clue cells in wet preparations
If small gram variable rods are in abundance in the vaginal secretions, according to Nugent score what does this mean?
G. Vaginalis
How does BV stick to epithelial cells?
Forms biofilms on the epithelial surface
What is used to treat BV?
Metronidazole
Metronidazole requires what type of environment for treatment?
Anaerobic; metronidazole can only be reduced to its active form in anaerobic organisms
What is the MOA of metronidazole?
Metronidazole is reduced by pyruvate:feredoxin oxidoreductase - interferes with bacterias fuel metabolism and generates reactive nitrogen
What effect does PID have on the epithelium of fallopian tubes?
Loss of ciliated epithelial cells; can result in infertility or ectopic pregnancy
What organism causes PID and is tiny, lacks a cell wall and requires cholesterol in growth media?
M genitalium
What gram negative coccobacilli can cause PID?
Hemophilus influenza
What two organisms may accompany neisseria of chlamydia in PID?
H influ; S pyogenes
What is the MOA of doxycycline?
Binds 30s ribosome and prevents tRNA binding; prevents protein synthesis
What is the gram stain and morphology of S aureus?
Gram positive cocci that grow in clusters; catalase positive coagulase positive, non-motile; facultative anaerobe
What is the importance of coagulase in S aureus?
Promotes fibrin activation and therefore wall that protects bacteria
What pathogenicity island is associated with TSST-1 production?
SaPI1
How is SapI1 spread?
Phage transduction
What organism is the penile flora predominated by?
Lactobacillus
Where is the most common site of viral entry?
The urethra and inner foreskin
What is part of the issue with having a foreskin and the increased susceptibility to STI infection?
The inner foreskin is non-keratinized, making it easier for pathogens to penetrate
What benefits does circumcision have?
Removes non-keratinized epithelium; shifts microbial community to aerobic bacteria which reduced inflammation and reduces the number of CD4+/CCR5+ macrophages in the urethra
