GU infections

Question 1

Double stranded DNA
Enveloped
Space between envelope and capsid is packed with tegument proteins

Answer 1

Alpha-Herpesvirus

Question 2

Two life cycles of HSV

Answer 2

1. Quiescent latent infection = limited to neurons (sacral ganglion), not associated with clinical symptoms
2. Lytic replication = active, many infectious viruses are produced, happens at the mucosa/skin at the site of initial inoculation

Question 3

Can HSV be transmitted if there are no lesions present?

Answer 3

Yes - on any given day have 25% chance of shedding virus even without lesions

Question 4

Diagnosis of HSV

Answer 4

Clinical presentation - vesicles
Detection of virus in lesions – culture, IFA, PCR
Detection of HSV-1 or HSV-2 specific antibodies

Question 5

Treatment of HSV

Answer 5

Famciclovir, Acyclovir – antivirals, nucleotide analogs that specifically target viral DNA polymerase and inhibit replication

NO TREATMENT for latent infection and no vaccine

Question 6

Very large linear double stranded DNA fused at both ends – Poxvirus family

Answer 6

Molluscum Contagiosum

Question 7

Where does Molluscum Contagiosum replicate?

Answer 7

In the cytoplasm of infected cells – unique for DNA virus

Question 8

How is Molluscum Contagiosum diagnosed and treated?

Answer 8

Diagnosis based on presentation of lesions and histology (large eosinophilic cytoplasmic inclusions)

Treated with scraping, liquid nitrogen, or iodine
More severe disease in immunocompromised patients can be treated with ritonavir or cidofovir. No vaccine.

Question 9

Small double stranded DNA virus
Papovavirus family
Icosahedral capsid, not enveloped

Answer 9

Human Papillomavirus

Question 10

How does HPV lead to disease?

Answer 10

Replicates in the upper level of epithelium – virus DNA has to be maintained as an episome for productive replication
Replication stimulates cellular division– etiology of HPV-induced genital warts

Question 11

How can HPV lead to cancer?

Answer 11

Accidental integration of broken viral DNA terminates virus replication –> abortive infection or cancer

Viral DNA integration that disrupts E2 gene increases risk of cancer along with expression of E6 and #7

Question 12

Treatment of HPV

Answer 12

Wart destruction in office by cryotherapy, or application of acid or removal with laser
Vaccine against high-risk strains (6, 11, 16, 18)

Question 13

Pleomorphic gram negative rods (coccobacilli)

Answer 13

Haemophilus ducreyi

Question 14

What does haemophilus ducreyi infection lead to?

Answer 14

Painful, ulcerated lesion with lymphadenopathy

Uncommon in US

Question 15

How is H. ducreyi diagnosed?

Answer 15

Culture or nucleic-acid based detection

Question 16

How is H. ducreyi treated?

Answer 16

Azithromycin, ceftriaxone, ciprofloxacin

Question 17

Pleomorphic gram negative rods

Part of normal vaginal flora in many sexually active women

Answer 17

Gardnerella vaginalis

Question 18

How does G. vaginalis cause disease?

Answer 18

Disturbance of normal flora leads to outgrowth, causing disease
Vaginal lactobacillus keeps G. vaginalis in check
Can synergize with anaerobes to cause disease

Question 19

How does G. vaginalis present?

Answer 19

Vaginitis, pruritis, dysuria, foul smelling copious vaginal discharge with fishy odor

Question 20

What is the diagnostic criteria of bacterial vaginosis?

Answer 20

Amsels criteria = 
Vaginal pH greater than 4.5
Presence of clue cells in vaginal fluid
Milky, homogeneous vaginal discharge
Release of amine (fishy) odor after addition of 10% NaOH

Question 21

Treatment for BV?

Answer 21

Nitroimidazoles (metronidazole and tinidazole) or clindamycin

Recurrence is common regardless of therapy

Question 22

Smallest free-living bacteria
Has no cell walls – gram stain and B-lactams are useless
Slow rate of growth

Answer 22

Ureaplasma urealyticum

Question 23

Treatment for ureaplasma urealyticum

Answer 23

Erythromycin

Doxycycline

Question 24

Gram negative spirochete
Extra outer membrane
Periplasmic flagella

Answer 24

Treponema pallidum

Question 25

What are the stages of sphyillis caused by Treponema pallidum?

Answer 25

Primary stage = painless chancre at inoculation site -- highly infectious Secondary stage = systemic spread to multiple organs and CNS Latent = asymptomatic and noninfectious, can relapse to secondary or remain asymptomatic Tertiary = immune system driven damage to multiple organs (skin, bones, vessels, nerves)

Question 26

How is syphilis diagnosed?

Answer 26

Cannot be cultured on conventional medium or seen on light microscopy Darkfield microscopy, serology and nucleic acid-based approaches

Question 27

Treatment of syphilis

Answer 27

Benthazine penicillin -- modified for slow absorption and long half life, not effective against tertiary stage

Question 28

Gram negative obligate intracellular bacteria

Answer 28

Chlamydia trachomatis

Question 29

2 forms of Chlamydia

Answer 29

Elementary body = metabolically inactive, cannot replicate, but infectious and stable Initial body = aka reticulate bodies, forms intracellular inclusions, metabolically active, intracellular non-infectious form, can divide and make more of itself

Question 30

Treatment for Chlamydia

Answer 30

Azithromycin and doxycycline

Question 31

Gram negative oxidase and catalase positive diplococci

Answer 31

Neisseria gonorrhea

Question 32

Diagnosis of Neisseria gonorrhea

Answer 32

Chocolate agar - nonselective Thayer-Martin - selective Culture Nucleic acid based used more now

Question 33

Treatment of Neisseria gonorrhea

Answer 33

Ceftriaxone

Question 34

Protozoa Trophozoite Males asymptomatic Females mild scant watery discharge or vaginitis with itching, burning and painful urination

Answer 34

Trichomonas vaginalis

Question 35

Diagnosis of Trichomonas vaginalis

Answer 35

Microscopic examination of vaginal or urethral discharge -- usually highly motile in urine

Question 36

Treamtent for Trichomonas vaginalis

Answer 36

Metronidazole (flagyl)

Question 37

Yeast Commonly in immunocompromised Can cause vaginitis

Answer 37

Candida albicans

Question 38

Diagnosis of candida albicans

Answer 38

KOH prep of skin scrapping

Question 39

Treatment of candida albicans

Answer 39

Imidazole vaginal suppositories or single oral dose of fluconazole