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Microbiology Part 1 > Lec20 Bacterial STDs > Flashcards

Lec20 Bacterial STDs Flashcards

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Biology 101 flashcards
1
Q

What bacteria causes syphilis?

A
  • treponema pallidum
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2
Q

What are micro features of treponema pallidum?

A
  • spirochete
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3
Q

What are the high risk groups for syphilis?

A
  • MSM, drug users, multiple sexual partners, common in HIV patients
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4
Q

What are the routes of syphilis transmission

A
  • sexual transmission: penetration via small abrasion on skin or mucus membrane
  • during early spirochetemia when negative RPR syphilis test, can be transmitted via blood transfusion
  • congenital [via placenta]
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5
Q

What are the four stages os syphilis?

A

primary, secondary, latent, late

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6
Q

How do you diagnose T. pallidum?

A
  • direct visualization of spirochete [darkfield microscopy, silver staining]
  • serologic testing
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7
Q

Can you diagnose T. pallidum from culture?

A

NO - T. pallidum does not grow in culture

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8
Q

What 3 types of serologic testing for syphilis?

A
  • RPR [inexpensive but non-specific, can be negative just after infection]
  • specific treponemal antibody test
  • syphilis IgG
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9
Q

What is RPR?

A
  • rapid plasminogen reagin
  • uses cardiolipin Ag and charcoal to test for reagin Ab
  • Charcoal gets trapped in latice from Ag-Ab rxn and seen microscopically
  • reagin antibodies develop from scell breakdown and always seen in syphilis
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10
Q

What are downsides of RPR?

A
  • very sensitive but not specific for syphilis
  • positive RPR needs to be confirmed with specific treponemal antibody test
  • get false positive from: some viral infections, TB, malaria, pregnancy, IDU [intravenous drug use], autoimmune diseae, other treponemal infections
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11
Q

What is the prozone effect?

A
  • when excess Ab, huge antibody titiers interfere with creation of Ag-Ab lattice
  • get false negative on RPR test
  • can sometimes occur in secondary syphilis
  • seen mostly in HIV + sisnce have broad polyclonal antibody response
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12
Q

What are signs of primary syphilis?

A
  • presence of chancre lesion
  • negative RPR early on
  • may not notice chancre because its painless
  • as chancre is healing, spirochetes enter blood stream and cause dissemination [spirochetemia] leading to secondary syphilis symptoms in half of patients
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13
Q

What are characteristics of chancre lesion?

A
  • sign of primary syphilis
  • painless
  • smooth ulcer with firm borders
  • no exudates
  • associated with painless lymphadenopathy
  • heals on its own in 3-6 wks
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14
Q

What is differntial diagnosis from a primary chancre?

A
  • chancroid
  • lymphogranuloma verenum [LGV]
  • herpes virus infection
  • traumatic lesion
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15
Q

What are signs of secondary syphilis?

A
  • period with highest spirochete antigen load
  • rarely can get prozone phenomemon [esp. with HIV]
  • if untreated can get secondary syphilis recurrences in 25%
  • rash [palm and sole involvement, trunk], fever, malaise, weight loss, diffuse painless LAD [lymphadenopathy], pharyngitis, arthralgias [joint pain]
  • asymptomatic CNS in some [elevated protein or plecytosis, sometimes symptoms of meningitis]
  • eye involvement [uveitis]
  • eventually immune beats and symptoms dissipate
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16
Q

What are condylomata lata?

A
  • large moist infectious plaques in places where skin rubs [axilla, etc]
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17
Q

What is latent syphilis?

A
  • period after infection when patient is asymptomatic but has reactive specific anti-treponemal antibody test
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18
Q

What are you looking for in LP for syphilis?

A
  • do it on pts with neuro/behavioral changes, with HIV, and failed treatment on penicilin G
  • looking for: leucocytosis, high protein or positive VDRL
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19
Q

How do you treat syphilis pt with positive lumbar puncture?

A
  • IV penicillin [PCN] for 10-14 days

- then weekly intramuscular PCN

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20
Q

What is late syphillis?

A
  • years to decades after infection

signs:
- aortitis
- CNS complications [meningo-vascular syphilis, general paresis = dementia/psychosis, tabes dorsalis = degeneration of nerves of dorsal columns of spinal cord]
- gumma formation [tumor like balls of inflammation, usually on bones

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21
Q

What is normal treatment for syphilis [primary, secondary, latent, late]? Other alternatives?

A

primary/secondary: single injection benzathine penicillin

latent: weekly benzathine penicillin
late: IV penicillin

No substitute for penicillin in late disease
for other stages can use: doxycyclin

22
Q

What syndomres asociated with chlamydia trachomatis?

A
  • genital infection
  • infant pneumonia + conjuncitivits
  • ocular trachoma
23
Q

What is ocular trachoma?

A
  • chronic follicular conjuncitivitis caused by chlamydia trachomatis
  • causes scarring of cornea so get vision loss –> blindness
  • spread from eye to eye or via autoinoculation from genital secretions
24
Q

What are the two biotypes of C. trachomatis and what do they cause?

A

trachoma biotype: causes all genital infections except LGV

LGV biotype: causes lymphogranuloma venereum [LGV]

25
Q

What is the most common bacterial STD in the US?

A

C. trachomatis

26
Q

What are affects of C. trachomatis in men? women?

A

men: causes urethritis, epididymitis
women: causes urethritits, cerviciits, acute salpingitis [chronic can lead to infertility]
- large proportion of cases asymptomatic

27
Q

How is chlamydia trachomatis spread?

A
  • infection occurs via abrasion

- can also be transmitted via direct inoculation into eyes or via respiratory tract in birth canal

28
Q

What is pathogenesis of chlamydia trachomatis?

A
  • causes by inflammatory response rather than tissue destruction
29
Q

What is life cycle of chlamydia?

A
  • biphase life cycle
    elemental body = extracellualr: attaches to and ingested by cells, surgives within phagosome by inhibiting phagolysosomal fustion via outer membrane proteins
  • differentiates into reticulate bodies = intracellular form: able to replicate within cell
30
Q

What are signs and symptoms of chlamydia trachomatis?

A
  • urethritis: pain/burning on urination, frequency
  • epididymtis: painful swelling of epididymis, erythema of scrotum
  • cervicitis: vaginal discharge, painful intercourse, irregular menses
  • salpingitis: fever, chills, lower abdomen pain
31
Q

What is lymphogranulomar vereneum?

A
  • caused by C. trachomatis
  • first stage: papule or ulcerative lesion
  • second stage days - wks later: regional tender lymphadenopathy, lessions form abscesses, coalesce and form masses [bubos]
  • third stage: granulomatous enlargement of external genitalia iwth ulceration
  • can also have anal ulceration with adenopathy
32
Q

How do you diagnose chlamydia?

A
  • for urehtritis, cervicitis, salpingitis: do nucleic acid amplification test to detect DNA/RNA
  • for lymphogranuloma venereum: do serum antibody assay for LGV serovars
33
Q

What is therapy for chlamydia?

A
  • treat empirically for chlamydia and GC
  • normal: azithromycin or doxycycline [azi better]
  • for neonatal: intravenous macrolide
  • can also use fluoroquinolones
  • azithromycin safe with pregnancy
34
Q

What are micro properties of neisseria gonorrhea?

A
  • bean shaped gram negative diplococci
  • all oxidase positive, most catalase positive
  • fastidious in nature, need nrutrients to grow –> use thayer martin media
35
Q

How is neisseria gonorrhea spread?

A
  • infection via sexual or perinatal transmission: M –> F higher risk than F–>M
36
Q

What are the virulence factors of neisseria gonorrhea?

A

pili: important for attachment to host cell, motility, transfer genetic material
outer membrane protiens
- Opa: important for attachment to host cell
- Por B: prevents phagolysosome fusion
- RMP: stimulate blocking Abs –> reduce bactericidal activity
- lipooligosaccharides [LOS]: have endotoxin activity, cause cell death of mucosal cells

37
Q

Who most commonly gets gonorrhea infection?

A
  • risk: complement deficiency, promiscuity, no condoms
  • adolescents and young adults
  • common in MSM
38
Q

What happens if untreated gonorrhea?

A
  • chronic pelvic pain

- ectopic pregnancy or infertility

39
Q

What are the symptoms of gonorrhea genital infection?

A
  • urethritis: dysuria, purulent urethral discharge
  • epididymitis
  • cervicitis
  • proctitis
  • pharyngitis
  • salpingitis [assocated with infertility]
  • perihepatitis
  • disseminated gonococcal infection [DGI]
40
Q

What is PID? symptoms? exam?

A
  • infection involving cervix, uterus, tubes, ovaries, pelvic peritoneum
  • manifests as endometritis or salpingitis
  • higher incidence in teen girls
  • common with secondary bacterial super-infection
  • symptoms: ab or pelvic pain, fever, chills, nausea, sepsis
  • exam: adenexal tenderness, CMT, discharge
  • long term causes ectopic rpegnancy/infertility
41
Q

What is Fitz Hugh Curtis Syndrome? signs?

A
  • there is a direct extension of gonorrhea from fallopian tubes to liver capsule
  • get right upper quadrant pain or diffuse ab pain
  • seen in women with acute PID
42
Q

What is disseminated gonococcal infection?

A
  • large spectrum of illness –> single large join arthritis, systemic febrile illness with toxicity, rahs, migratory polyarthritis
  • due to bacteremia or immune complex deposition
  • common in patients with terminal complement deficiency
43
Q

What happens in GC in late pregnancy? How do you treat?

A
  • newborn may get neonatal conjunctivitis –> untreated leads to blindness
  • treat neonate with prophylactic antibiotic ointment
44
Q

How can you diagnose GC? why two tests?

A
  • culture AND NAAT [nucleic acid amplification test]
  • NAAT won’t give you susceptibility data
  • can have low yield cutlure in asymptomatic patients
45
Q

What is the best way to culture for DGI?

A
  • use thayer-martin agar [chocolate agar with Abx]

- collect from urethra/cervix, blood, pharynx, and rectum

46
Q

What is treatment for gonorrhea?

A
  • ceftriaxone + azithromycin [or ceft. + doxi in case chlamydia]
  • if severe cephalosporin allergy: give azithro
  • treat partner
  • can’t use FQ or oral cefixime, resistance for PCN, tetracyclines, macrolides, fluoroquionolones, and more recently for cephalosporins
  • high rates of resistance so need to test for susceptibility
47
Q

What causes chancroid?

A

due to hemophilus ducreyi

asociated with drug use, sex trade, HIV transmission

48
Q

What is sign of chancroid?

A
  • ulcerative infection with painful adenopath

- painful ulcer, well circumscribes, necrotic base

49
Q

How do you diagnose chancroid?

A
  • culture of ulcer ecudate on chocolate agar

- if tender necrotic ulcer with lymphadenopathy and negative for syph/hsv

50
Q

how do you treat chancroid?

A

azithromycin, ceftriaxone, or ciproflaxicin

Microbiology Part 1 (24 decks)

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