Sexually Transmitted Infections Flashcards
What is the leading reported infectious disease in the U.S., and who has the highest prevalence?
Chlamydia trachomatis, highest among sexually active teenagers
What are the infectious and metabolically active forms of Chlamydia?
Infectious - elementary body
Non-infectious - Reticulate body
Which body has stainable inclusion bodies and why?
Reticulate body, because it synthesized large amounts of glycogen which can be stained via iodine
What two diseases is Chlamydia a major risk factor for in women and why?
- Reactive arthritis - often implicated
2. Pelvic inflammatory disease - develops in 20-40% of women, leads to ectopic pregnancy / infertility
What are typical symptoms of Chlamydia infection in women?
You can have cervicitis, salpingitis, or urethral syndrome, but it is asymptomatic in >50% of cases
What does Chlamydia cause in men?
Urethritis (urethral discharge easier to detect in men)
Epididymitis
Orchitis
Also: Reactive arthritis
What infection does Chlamydia cause in neonates?
Inclusion conjunctivitis or pneumonia
Why does Chlamydia cause PID?
Tissue fibrosis occurs as a result of chronic or recurring infection with strong inflammatory immune responses but no immunity to re-infection
What is Lymphogranuloma venereum? What Chlamydia serotypes cause this?
L1, L2, and L3 (for lympho).
Small, painless ulcers on genitals, leads to swollen, painful inguinal lymph nodes that ulcerate and cause buboes.
Common in MSM
What Chlamydia serotypes cause follicular conjuncitivitis?
Occurs chronically in africa.
Serotypes A, B, C
A = Africa
B = Blindness
C = Chronic
What Chlamydia serotypes cause urethritis / PID?
D - K = Everything else.
How is Chlamydia diagnosed?
Collection of infected epithelial cells from infection site, then PCR from vaginal swab or urine specimen (men)
Why are Chlamydia and Neisseria gonorrhoeae infections common co-infections?
Gonococcal infections facilitate transmission of Chlamydia
What are the general characteristics of gonococcus? What cells do they grow in
Gram negative diplococci with fastidious growth requirements, thus they are facultatively intracellular in PMNs (neutrophils) or epithelial cells
What is a Thayer-Martin plate and why are they used to isolate gonococcus?
Chocolate agar plate (fastidious growth requirements, like H. influenze) + antibiotics which reduce other GU flora which could grow with it
What is the primary adhesion virulence factor of N. gonorrhoeae and how does it attach and evade host immune response?
Pili - binds human CD46 membrane receptor
- RNA level = Slipped strand mispairing - Change the pilus length and create pilus plus and pilus minus (do not survive) phenotypes
- DNA level = Antigenic variation, PilE = expression, must recombine with pilS (several loci) to express different amino acid sequence in pilus protein
What causes a major inflammatory response in gonorrhea?
Lipo-oligosaccharide (LOS), the equivalent to LPS but the gonorrhea variant. Can be sialyated to confer serum resistance and block neutrophil attachment
This causes major of damage in disease
What does gonorrhea in men look like?
Urethra is primary site of infection, dysuria and purulent urethral discharge (as opposed to mucoid discharge of chlamydia)