Ulcerative STDs and Non-ulcerative STDs Flashcards
characteristics of spirochetes
3 kinds
spiral shaped
corkscrew mobility
don’t gram stain
grow slowly or not at all in vitro
treponema
borrelia
leptospira
haemophilus ducreyi
gram - coccobacilli
needs chocolate agar
causes CHANCROID
chancroid
soft chancre caused by h. ducreyi
– ragged ulcer on genitalia with swelling and tenderness; regional LN are often enlarged and tender
treponema
spirochete w no cell wall!
susceptible to penicillin
cannot grow in culture and cannot gram stain
-causes SYPHILLIS
see w darkfield microscopy, fluorescent antibody staining (DFA-TP), or silver stains
borrelia
zoonotic spirochete
visualize with giemsa or wright stain
CAN be cultivated!
causes lyme disease
leptospira
zoonotic spirochete
use darkfield or silver stains
can be grown
primary syphilis
primary lesion is a chancre due to treponema
heals spontaneously without treatment but the systemic infection persists in an asymptomatic form
Increased risk of HIV
secondary syphilis
lesions weeks later –> papulosquamous rashes (palms and soles), mucous patches (tongue), and genital lesions (condyloma lata)
heal spontaneously without treatment, but the systemic infection persists in an asymptomatic form
tertiary syphilis
lesions develop years after infection
targets include the CNS (neurosyphilis, meningovascular syphilis), CV system (syphilitic aortitis), and late benign syphilis (gummas)
diagnosing syphilis
Darkfield microscopy and Direct fluorescent antibody staining
o **CULTURES ARE NOT USEFUL for syphilis
treatment for syphilis (T pallidum)
penicillin G
distinguishing three bacterial STDs
gonorrhoeae, chlamydia, and mycoplasma/ureaplasma
Neisseria gonorrhoeae (gram negative diplococci) Chlamydia (obligate intracellular) Mycoplasma/ureaplasma (no cell wall)
neisseria gonorrhoeae
gram - diplococci
requires CO2
high antigenic variation allows rapid antibiotic resistance
neisseria gonorrhoeae virulence factors
colonization pili
transferrin, lactoferrin, and hemoglobin binding proteins
IgA1 protease
Opa (opacity) protein ligands
down regulate complement activation due to lack of capsule!
• Gonococcal Urethritis
frequent, urgent and painful urination with a yellow mucopurulent discharge
• Opthalmia Neonatorum
purulent conjunctivitis in newborn, can cause blindness; acquired during passage through birth canal
Curtis-Fitz-Hugh Syndrome
gonococcal dissemination into the peritoneum from the fallopian tubes and lead to perihepatitis
Gonococcal Upper reproductive Tract Infections (Male)
o Epididymitis; unilateral pain and swelling with low grade fever and chills; can also have painful urination, discharge from urethra, and blood in semen; pain on ejaculation
• Disseminated Gonococcal Infection (DGI)
hematogenous spread to skin and joints causing dermatitis, gonococcal arthritis, and endocarditis
what is a risk factor for disseminated gonoccoccal infection?
complement deficiency
• How can gonococci disseminate through bloodstream without a capsule?
o Porin-mediated serum resistance (2 porin types: P1A and P1B)
o Sialylation of gonococcal lipooligosaccharide (LOS) – by gonococcal sialyltransferase
How does gonorrhoeae damage the fallopian tubes?
o They adhere and directly damage w LOS and peptidoglycan
• Gonococci can REVERSIBLY ADAPT with varying surface molecules due to….
variable expression of 3 surface molecules
- -colonization pili
- -opacity (opa) proteins
- -LOS (lipooligosaccharide)
antigenic variation of colonization pili in gonorrhoeae
changes in pilin expression –> immune evasion; pilin variation is due to recombination
antigenic variation allows repeated infections!
gonorrhea incubation requirements
chocolate agar
37 degrees
5% CO2
gonorrhea treatment
ceftriaxone and azithromycin
three types of chlamydia
o C. pneumoniae – community acquired pneumonia
o C. psittaci – atypical pneumonia, endocarditis
o C. trachomatis — serovars are based on antigenic differences in the major outer membrane protein (MOMP)
–Serovars A-C = conjunctivitis, trachoma
–Serovars D-K = urethritis, cervicitis, inclusion conjunctivitis
–LGV serovars L1-L3 = lymphogranuloma venereum
chlamydia
- description
- forms
obligate intracellular bacteria cell envelope similar to gram negative bacteria BUT no detectable peptidoglycan o EB (elementary body) – small, extracellular infectious form; metabolically inactive o RB (reticulate body) – large, intracellular replicative form; metabolically active
• Chlamydial Urethritis – Nongonococcal Urethritis (NGU)
frequent urgent and painful urination
Usually asymptomatic with clear discharge (not purulent) in men
most common cause of non-gonococcal urethritis?
2nd most common?
Most common cause of NGU = Chlamydia trachomatis D-K (DicK)
second most common cause is ureaplasma urealyticum
reiters syndrome
urethritis, conjunctivitis, and polyarthritis
d/t chlamydia
o Infant inclusion conjunctivitis
acquired at birth from mother; acute mucopurulent discharge, erythema, and edema; silver nitrate prophylaxis is NOT effective
• Chlamydia trachomatis LGV infection (ulcerative STD)
tropism for lymphoid cells rather than epithelial cells; painless primary lesion regional lymphadenopathy 1-6 weeks later abscess formation necrotic foci =
treatment for chlamydia
azithromycin or tetracycline/doxycycline
o Infant conjunctivitis: oral erythromycin
mycoplasma / ureaplasma
cause nongonococcal urethritis (NGU)
• Mycoplasma has no cell wall!
• Lab diagnosis: inoculate medium (PPLO) colonies appear
nonoxynol-9
a spermicide that kills HIV but damages tissues so increases risk of STI!!!! BAD
• Gonorrhea increases transmission of HIV
how?
increases HIV viral load
and
inflammatory response brings in susceptible immune cells
vaccine for gonorrhea or chlamydia?
no
