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Infectious Disease Exam 1 > Bacterial STDs > Flashcards

Bacterial STDs Flashcards

1
Q

What is the etymology of the term “clap”?

A

It comes from a French word for brothel.

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2
Q

List the prevalence of STDs in the U.S.?

A

Chlamydia: 1,500,000
Gonorrhea: 400,000
Syphilis: 24,000

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3
Q

______________ is a facultative intracellular pathogen.

A

Neisseria gonorrhoeae

Remember the red cushions on the white chairs in the Sketchy scene.

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4
Q

If you have high specificity, then you have low ___________.

A

false positives

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5
Q

With low sensitivity, what will you have a lot of?

A

False negatives

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6
Q

____________ describes what percent of people without the disease will test negative.

A

Specificity

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7
Q

Oropharyngeal samples might test positive (falsely) for ______________.

A

Neisseria, because there are commensal bacteria that are intracellular Gram-negative diplococci

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8
Q

Gram stains for Neisseria gonorrhoeae have low _____________.

A

sensitivity (meaning high rate of false negatives)

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9
Q

Which strains of Neisseria are encapsulated?

A

N. meningitidis

(In the Sketchy scenes, the evidence in the college dorms is covered with glass domes, while in the nightclub scene the glass is broken on the floor!)

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10
Q

What virulence factor causes inflammation in Neisseria meningitidis?

A

Lipooligosaccharide (remember the LOS envelopes that are burning in the Sketchy college student’s dorm); these are the same as LPS but without the O sidechain

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11
Q

Neisseria require ___________ to grow.

A

5% CO2

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12
Q

Colonies turn ____________ in positive oxidase tests.

A

black

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13
Q

Both strains of Neisseria can ferment __________.

A

glucose

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14
Q

What two things are generally needed for a diagnosis of gonorrhea?

A
  • Either mucopurulent cervical discharge or exposure to an infected person
  • Growth on susceptible agar, PCR, or Gram stain showing Gram-negative diplococci
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15
Q

True or false: more men than women are asymptomatic carriers of gonorrhea.

A

False. Many more women are asymptomatic carriers (about 50%).

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16
Q

PID occurs in about _______ percent of female gonorrhea infections.

A

10

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17
Q

Untreated, gonorrheal conjunctivitis can cause __________.

A

corneal perforations

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18
Q

What age group has the highest incidence of gonorrhea?

A

15 - 24 (over 50%)

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19
Q

What mechanism allows Neisseria to escape the immune system?

A
  • Antigenic variation from amino acid switching in pili (can make up to 1,000,000 different forms)
  • Phase variation (on-off switching for expression of genes)
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20
Q

In the 1970s, Neisseria gonorrhea became resistant to _________________.

A

penicillins (due to expression of beta-lactamases)

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21
Q

______________ are no longer recommended for treatment of Neisseria gonorrhoeae due to widespread resistance.

A

Fluoroquinolones

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22
Q

_______________ is the only recommended therapy for gonorrhea.

A

Ceftriaxone and azithromycin

The macrolide can cover Chlamydia, but tetracycline can be substituted.

23
Q

Chlamydia are much _________ than Streptococcus.

A

smaller

24
Q

Which strains of Chlamydia are specific to humans?

A

C. trochomatis and C. pneumoniae

25
Q

How does Chlamydia survive inside cells?

A

It inhibits phagolysosome formation (meaning it is non-fusogenic).

26
Q

Most people infected with Chlamydia are ____________.

A

asymptomatic

27
Q

_____________ reproduce via transverse fusion.

A

Spirochetes

28
Q

________________ cannot be cultured in vitro.

A

Treponema pallidum

29
Q

Tertiary syphilis is ____________ transmissible.

A

not

30
Q

Syphilis initially travels by _____________.

A

lymphatics

31
Q

Describe the timeline of syphilis.

A 
Infection
Incubation period: 3 weeks
Primary syphilis: 2-6 weeks
Asymptomatic period: 2-24 weeks
Secondary syphilis: 2-6 weeks
Latent syphilis: 3-30 years
Tertiary syphilis
32
Q

What percent of people recover from syphilis infection?

A

~25%

33
Q

Describe the symptoms of each stage of syphilis.

A

Primary: painless chancre at site of lesion (usually as macule to papule to ulcer) and lymphadenopathy

Secondary: maculopapular rash, lymphadenopathy, alopecia, condyloma lata

34
Q

If you suspect syphilis but a person has a painful chancre, what organism might have caused this?

A

Haemophilus ducreyi

35
Q

The only sign or symptom of latent syphilis is _____________.

A

positive serologic testing

36
Q

What microscopy technique is needed to identify Treponema pallidum?

A

Darkfield microscopy

37
Q

____________ is more common in females and ___________ is more common in males.

A

Chlamydia; syphilis

Rates of gonorrhea are about the same between genders.

38
Q

Neisseria undergo rapid autolysis at ____________.

A

25º C or alkaline pH

39
Q

The best screening test for Chlamydia and N. gonorrhoeae is ____________.

A

NAAT (basically PCR)

40
Q

In someone with gonorrhea, it is important to contact and treat those who’ve had sex with that person in the past __________.

A

60 days

41
Q

How should gonorrhea be treated?

A

With intramuscular ceftriaxone and oral azithromycin (the latter for Chlamydial coinfection)

42
Q

Which stain helps identify Chlamydia?

A

Giemsa (like the GEMS from the Sketchy scene)

43
Q

How does Chlamydia cause conjunctivitis?

A

It causes the eyelids to turn inward, thereby scraping the eye continually and leading to conjunctivitis.

44
Q

Lymphogranuloma venereum can mimic ____________.

A

ulcerative colitis (because it can spread through the peritoneum)

45
Q

What is unique about Treponemal growth?

A

They divide by transverse fission.

46
Q

Can treponema persist in the environment?

A

Mostly no. They of course had to come from somewhere, but infection by fomites has not been documented.

47
Q

Which of the bacterial STDs is on the rise?

A

Syphilis

The incidence in 2015 was three times the incidence in 2005.

48
Q

Leptospirosis presents with damage to what organs?

A

Liver and kidney

49
Q

Which are larger, reticulate bodies or elementary bodies?

A

Reticulate

50
Q

What percent of untreated patients will develop tertiary syphilis?

A

30%

Note: this is now rare because antibiotics during the primary or secondary phase prevent this complication.

51
Q

Other than presence of pain, how can you distinguish H. ducreyi from syphilis?

A

H. ducreyi present with multiple ulcers while syphilis presents with a single indurated ulcer.

52
Q

Which immune pathway is responsible for the elimination of syphilis?

A

T-cells

53
Q

The Jarisch-Herxheimer reaction occurs in the ____________ stages of syphilis.

A

first and second

54
Q

Neisseria obtained a beta-lactamase from _________.

A

E. coli

Infectious Disease Exam 1 (17 decks)

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