STDs

Question 1

Most common notifiable disease in US?

Second most?

Answer 1

1. Chlamydia

2. Gonorrhea

Question 2

Gram - diplicocci

Answer 2

Neisseria

*each indiv cocci are kidney shaped

Question 3

Which one accounts for false positives, specificity or sensitivity?

Answer 3

Specificity

• tested 100 healthy people who did NOT have disease:
  what % of those have a NEGATIVE test

Question 4

Which one accounts for false negatives, specificity or sensitivity?

Answer 4

sensitivity

if you tested 100 people who knew had the disease:
How many would have a POSITIVE test?

Question 5

Ways to culture N. gonorrhoeae

Answer 5

1. Chocolate agar: nonselective
2. Thayer-Martin:
   more specific - contains ab
3. Transgrow bottle: provides CO2
   - N.g req. >3% CO2 for growth

Question 6

Which is strictly aerobic, N. gonorrhoeae or chalmydia?

Answer 6

N. gonor.

Question 7

Gold std to dz N. gonorrhoeae

Answer 7

1. Gram stain + culture on Thayer-martin or chocolate agar
2. Oxidase Test (positive)
3. Look for oxidative utilization of glucose (not maltose or sucrose)

Question 8

What can be used as an alternative to culture with vaginal specimens or urine from girls?

Answer 8

NAAT

- better sensitivity

Question 9

Why are preadolescent girls at higher risk for aquiring N. gonorrhoeae?

Answer 9

In cervix, developing cells are mostly columnar (at SCJ) cells: more adherent to Gonococcal cells

Question 10

Gonococcus directly infect ________ structures. Which can lead to these 6 things.

Answer 10

Mucosal and glandular structures

1. Opthlamia neonatorum
2. Urethritis
3. Pharyngitis
4. Cervicitis
5. Vulvovaginitis (children)
6. Proctitis

Question 11

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

Answer 11

Urethritis:

• prostatis
• vasiculitis
• epididymitis

Cervicitis:

• endometritis
• salpingitis
• oophoritis
• pelvic peritonitis

Question 12

Most common gonococcal complicaiton in men

Answer 12

acute epididymitis

Question 13

With neonatal conjunctivitis, what ab can you use?

Answer 13

Drops:
TCN
Erythromycin

• burnsssss (so try to prevent)

Question 14

Gonococcal bacteremia can cause distal infxns, name some

Answer 14

1. dermatitits
2. arthritis
3. endocarditis
4. meningitis
5. perihepatitis
6. tenosynovitis

Question 15

Designations of Major outer membrane proteins

Answer 15

1. Opa
   - imp for intimate attachment
   - undergo antigenic variation
   - undergo phase variation
2. Por
3. Rmp

Question 16

N. gonorrheae use:

1. antgenic variation
2. Phase variation

Answer 16

1. 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)
2. Phase variation
   - on-off control for expression of genes encoding surface proteins

• Both gives rise to antigenically and structurally diff pili

Question 17

tx option for gonorrhea?

Answer 17

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

Question 18

Chlamydia cell wall peptidoglycan is special how?

Answer 18

does not contain N-acetylmuramic acid

• PCN no good

Question 19

Chlamydia are diagnosed via:

Answer 19

NAAT
or visualized by:
1. bright field microscopy
- giemsa stain
2. electron microscopy
3. immnoflourescence microscopy

Question 20

Pathogenicity of chlamydia

Answer 20

1. attachment factors (adhesins)
2. inhibit phagolysosome fusion
3. latent infxn

Question 21

Trachomatic serovariants cause:
A-C
D-K
L1-L3

Answer 21

A-C: Inclusion conjunctivitis

D-K: STDs and infant conjunctivitis and pneumonia

L1-L3: lymphogranuloma venereum
- swollen inguinal ln

Question 22

Women vs men asymptomatic chlamydial infxns

Answer 22

75% women

50% men

• asymptomatic

Question 23

Most common cause of neonatal conjunctivitis in US

Answer 23

Chlamydia
- present 7-12 days after delivery

*unlike gonorrhea - more rapid presentation

Question 24

Spirochetes reproduce how?

- Can they be cultured in vitro?

Answer 24

reproduce by transverse fission

• T. pallidum cannot be cultured in vitro

Question 25

Which stages of syphilis is most transmissible?

Answer 25

stage 1+2 Primary: localized Secondary: systemic

Question 26

How many % of pts with untreated syphilis develop tertiary syphilis?

Answer 26

30% - 25% of that die of disease

Question 27

Incubation period of syphilis

Answer 27

~3 weeks | then primary syphilis lasts 2-6 weeks --> asymptomatic period

Question 28

What organism has painful chancroid ulcers?

Answer 28

Haemophilus ducreyi: GNB - not syphilis (painless)

Question 29

When are serologic tests highest during syphilis infxns?

Answer 29

serologic tests are highest in titer during secondary stage of syphilis

Question 30

Evidence of latent syphilis?

Answer 30

Only evidence is a POSITIVE SEROLOGIC TEST | - host suppresses infxn, and no lesions present

Question 31

Which is more protective in immunity to reinfection and protection against tertiary syphiis? - HUmoral or Cell mediated?

Answer 31

Cell mediated (T cell) response *humoral ab response is not protective but useful for dz

Question 32

Alternatives to treating syphilis if they are allergic to PCN?

Answer 32

Doxycycline Tetracycline

Question 33

rxn some pts get to syphilis tx?

Answer 33

Jarisch-Herxheimer rxn - develops 2-24 hrs after PCN tx in pts infected with spirochetes - occurs in 50% of pts with primary, and 90% of secondary - NOT AN ALLERGY TO PCN: explain to pt