Sexually Transmitted Infections

Question 1

What are the three bacterial species which produce STDs?

Answer 1

1) neisseria
2) chlamydia
3) treponema

Question 2

What are the morphological characteristics of Neisseria gonorrhoeae?

Answer 2

1) gram-negative
2) diplococci
3) oxidase positive

Question 3

Why are there no reliable animal models of gonorrhea?

Answer 3

because it only infects humans

Question 4

Which STDs have the highest incidence in the US?

Answer 4

1) chlamydia

2) gonorrhea

Question 5

What are the initial symptoms of a GC infection?

Answer 5

1) urethral or cervical discharge
2) dysuria
3) urethritis

Question 6

What does flank pain indicate on physical exam?

Answer 6

kidney infection or urinary tract involvement

Question 7

What is the differential diagnosis for gonorrhea?

Answer 7

Chlamydia, and then HIV and syphilis

Question 8

Why do you consider HIV and syphilis with GC infection?

Answer 8

Because STDs travel together!

Question 9

What two proteins cause gonorrhea to attach to the uretrhal or vaginal epithelium?

Answer 9

1) pilus protein

2) OPA protein

Question 10

How does gonorrhea infect a host?

Answer 10

endocytosis and transport into epithelial cells. exocytosis and collection by immune system. Host cell damage and then release to mucosal surface for reinfection.

Question 11

What is one of the signs of a gonorrhea infection?

Answer 11

PMN-rich exudate

Question 12

Where can a GC infection go especially in females?

Answer 12

Dissemination through the blood causing disseminated disease`

Question 13

What activates TNF in a GC infection?

Answer 13

LPS

Question 14

What is disseminated gonococcal disease characterized by?

Answer 14

skin lesions, traveling arthritis

Question 15

Where are 80-90% of GC cases found in women?

Answer 15

urogenital cervix

Question 16

What is a major side effect of GC infection in women?

Answer 16

PID

Question 17

What percentage of GC infections in women become PID?

Answer 17

10-20%

Question 18

What are two distinguishing characteristics of GC infection in women vs. men?

Answer 18

• 5x higher rate of being asymptomatic

- infection lasts longer - ~10 days

Question 19

What is the number one preventable cause of infertility in women?

Answer 19

PID

Question 20

How is GC diagnosed?

Answer 20

By taking a swab of the discharge

Question 21

How does GC grow on blood agar? on chocolate agar?

Answer 21

GC doesn’t grow on blood agar, but will grow on chocolate agar

Question 22

Why are false positives of GC a common occurrence in females?

Answer 22

Gram-negative diplococci are a common part of the normal vaginal microflora

Question 23

What are NAATs?

Answer 23

Nucleic Acid Amplification Tests

Question 24

What is the standard treatment for GC? Why?

Answer 24

Ceftriaxone 250mg and doxycycline. Ceftriaxone 250mg for growing resistance and doxycycline for NGU

Question 25

What is doxycycline used in treatment of GC infection?

Answer 25

Because Chlamydia symptoms show up later than GC and as co-occurring infections are common it is better to treat both

Question 26

What is NGU?

Answer 26

Non-gonococcal urethritis

Question 27

Which countries/regions have the highest rate of GC infection?

Answer 27

Former Soviet bloc countries, and parts of the MWern US

Question 28

Why is reinfection with GC common?

Answer 28

There is no immunity to GC. Antigenic variation occurs during infection

Question 29

What is the major adhesion protein in GC?

Answer 29

Pilin

Question 30

Why is pilin antigenically variable?

Answer 30

There are many gene cassettes of the pilin gene which can be tandemly arranged and recombined

Question 31

What are some unique properties of chlamydia bacteria?

Answer 31

- obligate unicellular bacteria - "energy parasite" using host's machinery to make ATP as it cannot on its own - cannot be cultured as it needs to have living cells to grow - similar to gram-negative bacteria

Question 32

What two forms does chlamydia come in?

Answer 32

1) elementary body | 2) reticulate body

Question 33

Which life form of chlamydia is infectious?

Answer 33

elementary body

Question 34

Which life form is larger?

Answer 34

reticulate body

Question 35

Which life form is intracellular?

Answer 35

reticulate body

Question 36

Where is chlamydia primarily pathogenic?

Answer 36

cervical and urethral epithelium

Question 37

What are the two antibiotics which Chlamydia is primarily susceptible to?

Answer 37

- tetracyclines | - erythromycin

Question 38

What is the bacteria which causes syphilis?

Answer 38

treponema pallidum

Question 39

What type of shape is treponema?

Answer 39

spiral-shaped rod

Question 40

Can syphilis be cultured?

Answer 40

no!

Question 41

What is the characteristic lesion in primary syphilis?

Answer 41

chancre

Question 42

What is a chancre?

Answer 42

firm, painless, non-itchy skin ulceration

Question 43

What is the reservoir for syphilis?

Answer 43

Humans only

Question 44

What population has a higher incidence of STDs in general?

Answer 44

HIV+ individuals

Question 45

If syphilis is untreated, what happens?

Answer 45

You get a larger rash with palmar and solar lesions which indicates secondary syphilis

Question 46

How long can syphilis stay latent?

Answer 46

3-30 years

Question 47

Which population has an increase in the incidence in syphilis in the past 15 years?

Answer 47

males who have sex with other males

Question 48

How do you work-up syphilis?

Answer 48

- dark-field or fluorescent microscopy - antibody tests - GC, chlamydia, and HIV screens if negative

Question 49

What is the primary treatment of choice for syphilis and why?

Answer 49

Pencillin because there is little if any abx resistance

Question 50

Is the treponema bacteria particularly hardy?

Answer 50

No, it cannot survive away from humans, nor in heat, other conditions.

Question 51

Why is syphilis sometimes called the "great imitator"?

Answer 51

Because its primary symptoms mimic those of other diseases