STDs

Question 1

Neisseria gonorrhoeae

Answer 1

Gram neg diplococci. Aerobic. Obligate human. Oxidase pos. Bugs inside neutrophils. Will use glucose but no maltose/sucrose
Media: Chocolate, Thayer- Martin, Transgrow. Requires CO2
High infectivity

Question 2

Neisseria gonorrhoeae Virulence factos

Answer 2

Pili - attachment
Opa proteins=outer membrane proteins important for attachment
lipo-oligosaccharide (LOS) - toixc for ciliated cells
IgA protease cleaves Fc of IgA

Question 3

Neisseria gonorrhoeae Infections

Answer 3

Ophthalmia neonatorum
Gonococcal infection in preadolescent children is most frequently due to sexual abuse
cervicitis, abscess
of glands adjacent to vagina, urethritis, endometritis, PID
Disseminated gonococcal infection: dermatitis-arthritis-tenosynovitis syndrome, monoarticular septic arthritis, endocarditis, meningitis

Question 4

Neisseria gonorrhoeae Tx

Answer 4

often also infected with C.
trachomatis so TREAT BOTH
Neonates: slive nitrate/antibio drops at birth
250 mg IM Ceftriaxone (for gonorrhea) + 1 g oral Azithromycin (for Chlamydia)

Question 5

Chlamydia trachomatis

Answer 5

Gram neg, obligate intracellular.
Most freq. reported STD.
Infected women 3/5x up HIV risk
Replicate by binary fission 
Has LPS
Can visualize with Giemsa stain see intracellular inclusions near nucleus (inclusions are brown with Lugol’s iodine stain)

Question 6

Chlamydia trachomatis Infxns

Answer 6

Trachoma: Chronic keratoconjunctivitis (acute
inflammation that can progress to scarring and blindness). 3-10 d incubation
Inclusion conjunctivitis: Acute,Mucopurulent conjunctivitis 7-12 d after. Can cause pneumo
UTI: Men: dysuria, dishcharge, urethritis Women: urethritis, cervicitis, PID
Lymphogranuloma Venerum: Small ulcer on genitalia, inguinal LAD, can disseminate to peritoneum

Question 7

Chlamydia Tx

Answer 7

Conjunctivitis: erthro/tetracycline
Urogenital Tract Infections: 1 g oral Azithromycin or 100mg BIDx7d Doxycycline
Lymphogranuloma Venerum: sulfonamides and tetracylcline (early); surgery (late)

Question 8

Treponema Pallidium

Answer 8

Spirochete. Gram neg, but no LPS = doesn’t stain. Have endoflagella. Contagious 3-5 years. Often w/illicit drug use
LM: not seen unless DFA-TP stain or Darkfield illuminated
Nontreponemal antigen tests
VDRL or RPR tests
Treponemal antibody test = Fluorescent Treponemal
Antibody (FTA)

Question 9

Syphilis Stages

Answer 9

Primary: one or more chancres
Secondary: wks after primary, mucocutaneous lesions/rash, alopecia, generalized LAD, “nick/dime” lesions, serologic tests are highest in titer during this stage
Latent syphilis: post serology = only sign
Neurosyphilis: tabes dorsalis & reactive VDRL in CSF
Late benign syphilis and cardiovascular syphilis: inflammatory lesions of CV system, skin, and bone; 15-30 yrs later
Stillbirth syphilis: fetal death at ~20wks

Question 10

Non-sexually spread Syphillis

Answer 10

Yaws (T. pallidum subsp pertenue):
endemic in kids in tropics; ulcerating papule on legs or arms
Endemic Syphilis/Bejel (T. pallidum subspendemicum): skin lesions; kids in Africa,
Middle East, SE Asia
Pinta (T. carateum): nonulcerating papule, progress to flat hyperpigmented lesion yrs later depigmentation and hyperkeratosis; Mexico , Latin America, Philippines

Question 11

Syphilis Tx

Answer 11

Penicillin!
Jarisch- Herxheimer reaction: fever, HA, sweating ~2-24 hrs after PCN (thought increased cytokine response to release of antigens; occurs with treatment of secondary syphilis)
Use azithromycin or doxy if allergy

Question 12

Herpes Viruses General Info

Answer 12

Large, linear dsDNA in icosahedral capsids covered in tegument. Envelope from host membrane.
Replication: attach & entry (by viral glycoproteins) -> uncoating & circularizes -> expression: immediate (IE or alpha) transcription reg proteins, then early (E or beta) proteins for rep, then late (L or gamma) capsid, tegument, membrane glycoproteins -> replication using virally encoded DNA polymerase -> virion assembly

Question 13

Varicella Zoster

Answer 13

mucosal epithelium
Latency in multiple sensory nerve ganglia
Incubation 10-21 days
Chickepox = 'dew drop on rose petal'
Shingles = confined to dermatome, post-herpetic neuralgia
Live VZV vaccine at 1 & 5
Zostavax vaccine > 50 
Acyclovir w/in 2/3 days

Question 14

CMV

Answer 14

Beta herpes virus
Targets epithelia, monocytes, lymphocytes,
Latent in mono,lymphocytes
Mono-like syndrome.
CMV in 10% newborns but usually mild unless primary infection in mom
Tx = ganciclovir

Question 15

CMV

Answer 15

Beta herpes virus
Targets epithelia, monocytes, lymphocytes,
Latent in mono,lymphocytes
Mono-like syndrome. 
CMV in 10% newborns but usually mild
Tx = ganciclovir

Question 16

HHV- 6/7

Answer 16

Targets T cells
Latency in myeloid cells (T cells)
Roseola Infantum/Exanthem subitum
High fever -> rash appears in 20-30% as the fever abruptly subsides starts on trunk and goes to extremities

Question 17

EBV

Answer 17

Target B-cells, nasopharyngeal epithelia. >97% adults have Ab.
Infectious mono, Burkitt’s lymphoma, Hodgkin’s, nasopharyngeal carcinoma, post-transplant lymphoproliferative disorder
Dx = heterophile test

Question 18

KSHV/HHV-8

Answer 18

Targets lymphocytes, endothelium
Latency in B cells
Kaposi’s sarcoma - cellulitis in HIV
Peritoneal effusion lymphoma
Multicentric Castleman’s Disease
Sexually spread

Question 19

HSV1

Answer 19

Targets mucosal epithelium
Latency in trigememinal ganglia
usually spread via asymptomatic shedding
Most asymp, orofacial, fingers (whitlow), keratitis. Rare encephalitis

Question 20

HSV Dx & Tx

Answer 20

Viral culture of lesion
Direct fluorescent antibody stain
Tzanck smear
Acyclovir

Question 21

HSV2

Answer 21

Targets mucosal epithelium
Latency in sacral ganglia
Transmit by sexual contact
Usually aymp or genital lesions
Can be severe in compromised or neonates - suspect if ulcer/crusted lesion