GU Infections- Davis/Lumen/Tarakanova Flashcards
What defense mechanisms do humans have against STIs?
Males
- Epithelial cells - barrier and antigen presentation
- Native flora- competes for resources
- Urethral length- UTI migration
- Urine stream- UTI migration
- Circumcision- prevents HIV, HPV, HSV transmission
Females
- Epthelial cells- barrier and antigen presentation
- Native flora- competes for resources
- Lactobacillus lowers vaginal pH
What sexual practices most reduce the risk of STIs?
Which groups are considered “special populations” in terms of STI management?
- Abstinence
- Reduce number of partners
- Pre-exposure vaccine
- Condom use
- Pregnant women- STIs may affect course of pregnancy
- Adolescents/Children- lack of maturity about sex/ may indicate abuse
- Correctional Facilites- usually very high rates
- MSM- sexual practices may raise risk of STI
- WSW- may “transmit” infections back and forth
Which STIs produce painful lesions?
Which STIs produce non-painful lesions?
Painful
- Herpes
- Chancroid
- Lymphogranuloma venereum
Non-Painful
- Syphilis
- Molluscum
- Genital Warts
What are clue cells?
What disease do they indicate?
Clue cells are GU epithelial cells with irregular, shaggy borders
They indicate bacterial vaginosis.
What older test is generally preferred to test for bacterial vaginosis?
What is the CDC-recommend diagnostic test for bacterial vaginosis?
Amsels Criteria
- Vaginal pH above 4.5
- Clue cells in fluid
- Milky vaginal discharge
- Fishy odor, esp after adding 10% KOH
CDC recommends nucleic acid-based diagnosis using DNA probes
What organism is typically responsible for bacterial vaginosis?
How is bacterial vaginosis treated?
Gardnerella Vaginalis, pleomorphic gram negative rod
Treated with Nitroimidazoles (aka metronidazole) or Clindamycin either can be oral or topical
How is Candidiasis diagnosed?
How is it treated?
How does it present?
Microscopic smears will show high concentrations of candida
Imidazole suppository or single dose of oral fluconazole
May present with discharge, but more likely with UNBELIEVABLE ITCHING (which was not mentioned in class for some reason)
What type of genome does the herpes virus have?
What is the architecture of the herpes virus?
Double stranded DNA
Envelope- Tegument- Capsid
Viral and cellular proteins collect in the tegument
What types of cells do herpes viruses infect in the lytic stage and in the latent stage?
How does the genome structure in the latent infection allow switching to a lytic infection?
In the lytic phase, HSV typically infects epithelial cells; in the latent phase, it affect neurons.
In the latent infection, the bacterial genome is stored as an episome, which can allow the virus to activate at any time.
How is herpes diagnosed?
How is herpes treated?
PCR, immunofluorescence of HSV from active lesions OR antibody tests during latency
Famciclovir will treat lytic phase, but there is no cure or vaccine for the latent phase.
How does herpes present?
How does herpes affect pregnancy?
Present as painful ulcers, crusted ulcers, or vesicles
Herpes can be transmitted during vaginal delivery, so C-section is necessary.
What type of genome does molluscum contagiosum have?
Where does it replicate? How does this appear on histology?
Double-stranded DNA
It replicates exclusively in the cytoplasm of epithelial cells; molluscum bodies, or large eosinophilic cytoplasmic inclusions are seen on histology.
How does molluscum contagiosum present?
How is it treated?
Presents as clusters of painless, wart-like nodules
The virus is typically cleared by the body naturally; however, nodules can be physically removed and acyclovir/famciclovir can be given to the immunosuppressed.
What type of genome does HPV have?
What architecture is seen in HPV?
Double Stranded DNA
Icosahedral capsid, no envelope
What happens to the genome during replication?
What results from HPV replication?
The genome is stored as an episome in the nucleus of the cell
Epithelial proliferation results in a wart
What strains of HPV are considered “high risk”?
Why are these strains high risk?
16, 18, 31, 45
They carry an increased risk of cervical cancer due to the expression of E6 and E7, which can cause genome integration
How is HPV diagnosed?
How is it treated?
Can be diagnosed via PCR of a wart or from a pap smear
Removal of warts and administration of the vaccine Gardasil (uses caspid protein L1)
What type of architecture does haemophilus ducreyi have?
How does it use oxygen?
Pleomorphic gram-negative rod
Facultative anaerobe
How does Haemophilus ducreyi infection present?
What secondary STI are you more at risk for when infected?
Tender papule that progresses to a PAINFUL ulceration with unilateral lymphadenopathy
HIV infection (and presumably HPV as well) due to open wound
How is Haemophilus ducreyi diagnosed?
How is it treated?
Diagnosed by culture or PCR of an ulcer or lymph node aspiration
Treated with ceftriaxone, ciprofloxcin, or azithromycin
What is the architecture of ureaplasma urealyticum?
What enzymes does it produce?
Pleomorphic without cell walls (It’s a mycoplasma)
Urease; it cleaves urea in the urine into ammonia giving it a fishy smell
What symptoms does a ureaplasma urealytica infection present with?
How is it diagnosed?
Dysuria and yellow, mucoid discharge (probably also fishy smell)
Diagnosed via PCR; can be cultured, but requires urea, cholesterol and forms very small colonies
How is ureaplasma urealytica treated?
What class of antibiotics would not work?
Erythromycin and Tetracycline
Beta-lactams won’t work because it has no cell wall
What is the architecture of treponema pallidum?
What disease does it cause?
Gram negative spirochete with a flagella
Syphilis
