STDs Flashcards
Most common notifiable disease in US?
Second most?
- Chlamydia
2. Gonorrhea
Gram - diplicocci
Neisseria
*each indiv cocci are kidney shaped
Which one accounts for false positives, specificity or sensitivity?
Specificity
- tested 100 healthy people who did NOT have disease:
what % of those have a NEGATIVE test
Which one accounts for false negatives, specificity or sensitivity?
sensitivity
if you tested 100 people who knew had the disease:
How many would have a POSITIVE test?
Ways to culture N. gonorrhoeae
- Chocolate agar: nonselective
- Thayer-Martin:
more specific - contains ab - Transgrow bottle: provides CO2
- N.g req. >3% CO2 for growth
Which is strictly aerobic, N. gonorrhoeae or chalmydia?
N. gonor.
Gold std to dz N. gonorrhoeae
- Gram stain + culture on Thayer-martin or chocolate agar
- Oxidase Test (positive)
- Look for oxidative utilization of glucose (not maltose or sucrose)
What can be used as an alternative to culture with vaginal specimens or urine from girls?
NAAT
- better sensitivity
Why are preadolescent girls at higher risk for aquiring N. gonorrhoeae?
In cervix, developing cells are mostly columnar (at SCJ) cells: more adherent to Gonococcal cells
Gonococcus directly infect ________ structures. Which can lead to these 6 things.
Mucosal and glandular structures
- Opthlamia neonatorum
- Urethritis
- Pharyngitis
- Cervicitis
- Vulvovaginitis (children)
- Proctitis
Gonococcus can locally extend and cause urethritis and cervicitis, which can also result in bacteremia and cause distal infxns. List what happens with local extensions
Urethritis:
- prostatis
- vasiculitis
- epididymitis
Cervicitis:
- endometritis
- salpingitis
- oophoritis
- pelvic peritonitis
Most common gonococcal complicaiton in men
acute epididymitis
With neonatal conjunctivitis, what ab can you use?
Drops:
TCN
Erythromycin
- burnsssss (so try to prevent)
Gonococcal bacteremia can cause distal infxns, name some
- dermatitits
- arthritis
- endocarditis
- meningitis
- perihepatitis
- tenosynovitis
Designations of Major outer membrane proteins
- Opa
- imp for intimate attachment
- undergo antigenic variation
- undergo phase variation - Por
- Rmp
N. gonorrheae use:
- antgenic variation
- Phase variation
- antgenic variation
- change the aa seq of surface proteins
- same fxn, but no longer rec by immune sys
- can be due to recombination (btwn two organisms with diff copies of pilin gene - 1 silent, 1 fxnal) - Phase variation
- on-off control for expression of genes encoding surface proteins
- Both gives rise to antigenically and structurally diff pili
tx option for gonorrhea?
3rd gen cephalosporins
- ceftriaxone IM (in the butt) or cefixime PO both are given with azithromycin (chlam)
- last line def for treating
*FQ are no longer recommended due to resisitance
Chlamydia cell wall peptidoglycan is special how?
does not contain N-acetylmuramic acid
- PCN no good
Chlamydia are diagnosed via:
NAAT or visualized by: 1. bright field microscopy - giemsa stain 2. electron microscopy 3. immnoflourescence microscopy
Pathogenicity of chlamydia
- attachment factors (adhesins)
- inhibit phagolysosome fusion
- latent infxn
Trachomatic serovariants cause:
A-C
D-K
L1-L3
A-C: Inclusion conjunctivitis
D-K: STDs and infant conjunctivitis and pneumonia
L1-L3: lymphogranuloma venereum
- swollen inguinal ln
Women vs men asymptomatic chlamydial infxns
75% women
50% men
- asymptomatic
Most common cause of neonatal conjunctivitis in US
Chlamydia
- present 7-12 days after delivery
*unlike gonorrhea - more rapid presentation
Spirochetes reproduce how?
- Can they be cultured in vitro?
reproduce by transverse fission
- T. pallidum cannot be cultured in vitro
