Microbiology of your junk

Question 1

What are the primary non-ulcerative STIs?

Answer 1

N. gonorrhoeae C. trachomatis (servars D-K) Mycoplasma and Ureaplasma

Question 2

Gram -

no detectable peptidoglycan

DNA, RNA, 70s ribosomes

Intracellular pathogen

Answer 2

Chlamydia trachomatis

Question 3

Gram negative Capnophilic Pyogenic coccus

Answer 3

N. gonorrhoeae

Question 4

What type of infections does N. gonorrhoeae cause?

Answer 4

Urethritis in men>women Cervicitis 50% asymptomatic Pharyngitis Proctitis Opthalmia neonatorum PID, Endometritis, Salpingitis Epididymitis DIG

Question 5

Discribe the manifestations of disseminated gonococcal infection.

Answer 5

Dermatitis-hemorrhagic papular lesions, fingers, wrists and feet (Reactive) Arthritis-large joints, synovial fluid cultures postive in 30% Endocarditis

Question 6

What are gonococcal virulence factors?

Answer 6

colonization pili - adheres to epithelium
Fe receptors - lactoferrin, transferris, Hb
IgA1 specific protease
Opa proteins - invade epithelial cells
LOS - addition of host derived sialic acid
Porin P1A & P1B bind C4bp and FH

Question 7

Why are repeated gonococcal infections so common?

Answer 7

Homologous recombination of the pilE genes with pilS loci results in 10^17 different types of pili May be immunosuppressive by inducing Th17 pathway

Question 8

How is gonorrhea diagnosed in the laboratory?

Answer 8

Gram stain -95% sensitive in men, 50-70% in women PCR/DNA (NAAT) - urine or cervical discharge Culture - chocolate or thayer martin in candle jar

Question 9

What is current treatment for gonococcal infections?

Answer 9

ceftriaxone with azithromycin or doxycycline

Question 10

Symptoms of Chlamydial Urethritis/cervicitis?

Answer 10

Men -symptomatic discharge clear

Women -usually asymptomatic

LGV-ulcerative disease of the lymphatics

Question 11

What can an ascending Chlamydial infections result in?

Answer 11

Reiter’s syndrome (urethritis, conjunctivitis, polyarthritis) Epidydimitis Endometritis, salpingitis, PID

Question 12

What is the most common form of neonatal conjunctivitis in the US?

Answer 12

Chlamydial conjunctivitis

Question 13

What are elementary bodies and reticulate bodies?

Answer 13

EM-extracellular, infectious, metabolically inactive form of C. trach. Contains disulfide cross-linked outer membrane proteins

RB-Larger, intracellular replicative form of C. trach. Osmotically fragile

Question 14

What is the pathogenesis of C. trachomatis?

Answer 14

induce acute and chronic inflammation
cytopathic effect on host cells

tissue damage (fallopian tube scarring) caused by host response

heat shock proteins may play a role

Question 15

How is Chlamydia diagnosed?

Answer 15

NAAT

direct fluorsecent antibody test
Culture with MOMP-specific antibody

Question 16

How is Chlamydia treated?

Answer 16

single dose of azithromycin

Tetracycline or Doxy for 7 days

LGV- doxy for 21days

Conjunctivitis- oral erythromycin

Question 17

Ureaplasma urealyticum and Mycoplama genitalium account for what percent of nongonococcal urethritis cases?

Answer 17

20%

Question 18

How do you diagnose Mycoplasma/Ureaplama spp.?

Answer 18

rule out other causes
Inoculate specail transport media (PPLO)
Colonies will appear on solid agar plates in 2-5 days

Nuc. acid and other rapid diagnostic tests in development

Question 19

What’s the most common CDC reportable STI?

Answer 19

Chlamydia trach.

Question 20

How does coinfection affect HIV transmission?

Answer 20

Increases it

• inflammatory response brings WBCs to site of infection
• HIV viral load higher in gonorrhea secretions
• ulceritive STIs increase suceptibility

Question 21

Why are younger women at increased risk of Chlamydia and Gonorrhea?

Answer 21

Cervical ectopy

columnar epitheilium less resistant to infection

Question 22

What is nonoxynol-9 and how does it affect STI transmission?

Answer 22

Spermicide
increases transmission by disrupting endothelial cells (detergent action)

inflammation brings in WBCs for HIV to infect