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Microbiology 2 > M7 Genital Tract Infections > Flashcards

M7 Genital Tract Infections Flashcards

1
Q

What is normal flora for the urethra?

A

Coag neg Staph & Corynebacterium, some anaerobes (skin-like)

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2
Q

What normal flora organisms may the Vulva & penis (prepuce) have?

A

May have Mycobacterium smegmatis & other Gram+

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3
Q

What does the female genital normal flora vary with?

A

Female varies with pH and estrogen (age).

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4
Q

What organisms are in the female prepubescent and menopausal normal flora?

A

Prepubescent & menopausal:
Staph & Coryne (skin-like)

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5
Q

What organisms are in the female reproductive age normal flora? How do they provide protection?

A

Reproductive age:
Enterobacterales
Staph- Strep
Anaerobes (varied, mainly
Lactobacillus)–> Predominant
Keeps pH @ 4 + H2O2+ –>protection

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6
Q

What is the difference between exogenous and endogenous genital infections?

A

Exogenous: from interaction with others (STI’s)
Endogenous (from normal flora)

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7
Q

What parts of the female are considered lower genital tract and what parts are upper genital?

A

Female
1. Lower genital tract (vulva, vagina, cervix)
2. Upper genital tract (reproductive + abd cavity)

Infections can start as a lower and progress to upper (same in males: from urethral infection to epididymis)

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8
Q

How many sexually transmitted genital infections can you list?

A

Sexually transmitted:
1. Urethritis-cervicitis
a. Chlamydia trachomatis
b. Neisseria gonorrhoeae
2. Trichomonas vaginalis
3. HIV
4. Treponema pallidum (Syphilis)
5. Ureaplasma urealyticum
6. Mycoplasma hominis
7. Herpes simplex virus

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9
Q

How many genital infections (non-sexually transmitted) can you list?

A
  1. Vaginitis: Candida,
    Trichomonas
  2. Bacterial vaginosis
  3. E. coli or other GNB in prepubescent
  4. Strep Gr B and Listeria in pregnancy
  5. S. aureus in Toxic shock syndrome
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10
Q

What type of transport medium is used on a vaginal swab for GC?

A

Amies or Stuart’s Transport Media w/charcoal
- salt and mineral concentrations conducive to recovery of pathogens including N.gonorrhoeae
- charcoal is added to further increase recovery of N.gonorrhoeae

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11
Q

What are the transportation limitations for GC?

A

Storage of specimens: for GC, ideally less than 12 hours of transport at R.T. (No fridge!)
or a special commercial system or planting straight to plates.

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12
Q

What organisms are included in a prenatal screen?

A

Streptococcus agalactiae:
Screening with LIM broth (enrichment), then subbed to BA
Now Chromogenic agar is starting to be used.

Listeria monocytogenes, cultured under request (BA)

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13
Q

How can prenatal infections occur with S. agalactiae (Group B)?

A
  1. Rupture of vaginal membranes during birth lead to infection in neonates
  2. Late trimester fetus or neonates primarily affected (not the pregnant woman)
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14
Q

How can prenatal
infections occur with L. monocytogenes?

A
  1. Dissemination of organism through the bloodstream
  2. Early trimester fetus primarily affected

Looked for in stillbirth samples (NP swab of baby and placenta swab)

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15
Q

How does the typical hemolysis of S. agalactiae compare with Group A Strep?

A

S. agalactiae – dull narrow zone hemolysis

Whereas Group A strep typically has a wider zone of hemolysis.

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16
Q

What colony morphology is expected and tests are performed for suspected S. agalactiae?

A
  1. Colony description: sm grey/wt beta haem (narrow)
    • the sole member of Lancefield group B, forms small 3 to 4 mm, grey-white colonies that have a narrow zone of beta hemolysis on blood agar.
  2. Gram : G+ c prs, chains
  3. Catalase: θ
  4. Bac – Res; CAMP +
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17
Q

What is the final confirmatory test for suspected S. agalactiae?

A

Latex agglutination with specific antisera: Lancefield identified the group B antigen, a cell wall-associated carbohydrate that distinguishes GBS from other streptococcal species.

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18
Q

What does the CAMP test look for in S. agalactiae?

A

A positive GBS Camp test shows a positive zone of enhanced hemolytic activity (shown by arrow head), whereas a non-positive test shows a non-enhanced zone of hemolytic activity.

S. Agalactiae produces a CAMP factor that enhances hemolysis when it acts synergistically with a beta-lysin producing strain of S. Aureus.

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19
Q

What is the colonial morphology of Listeria spp.? How can it be confused with Group B strep?

A

Colonial Morphology:
β-sm trans
has a narrow-zone β-hemolysis on sheep blood agar, resembling Group B strep

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20
Q

What does Listeria spp. look like on a gram stain?

A

Listeria spp. gram stain:

Gram positive bacilli which can resemble cocci or coccobacilli.

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21
Q

Liquid media shows bacilli forms more apparent, T or F?

A

True: CSF
bacilli forms more apparent
in liquid media

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22
Q

What tests are performed to confirm suspected Listeria spp. ID?

A

Catalase positive
Enhanced motility at cooler temperatures (20o-25oC) (end-over-end in wet mount, umbrella pattern in soft agar)
API Listeria or other automated methods (Vitek, Maldi-Tof)

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23
Q

What four organisms are the main causative agents of STI’s?

A

Neisseria gonorrhoeae
Treponema pallidum
Trichomonas vaginalis
Chlamydia trachomatis

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24
Q

What pathogenicity factors does N. gonorrhoeae have?

A
  1. Attachment to epithelial cells via pili major virulence factor
  2. Inflammatory response leads to engulfment of gram negative diplococci by neutrophils
  3. Destruction of bacteria by
    host defenses hindered by
    pili
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25
Q

What pathogenic symptom does N. gonorrhoeae cause?

A

Symptoms include purulent
discharge.

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26
Q

What are the most common body part in male & female specimens are taken for Neisseria gonorrhoeae (GC)?

A

Common specimens
Urethral (male)
Cervix (female)

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27
Q

What other specimens from which body parts can be taken for Neisseria gonorrhoeae (GC)?

A

Other specimens
Rectal
Vaginal
Throat
Eye
joints

28
Q

What type of special agar medium should be used for Neisseria gonorrhoeae (GC)?

A

Modified Thayer Martin (more
common) BA base + Hem +
supplement + VCNT

New York City Agar (grows GC +
Mycoplasma)

29
Q

List the inhibitory components in Modified Thayer Martin.

A

VCNT: Vancomycin (inh. GP’s), colistin (inh. GN’s),
Nystatin (antifungal), Trimethoprim (Proteus & others)

30
Q

Why should you also plant a GC specimen on chocolate agar too? Would you do a BA plate.

A

Some GC’s are inhibited by Thayer Martin so a choc. plate is planted too.

You would not do a BA plate as N. gonorrhoeae does not grow on it.

31
Q

What is done if there is no growth after 72 hours on a plate for GC?

A

Flood media with oxidase after 72 hours incubation

32
Q

What does intracellular g-dc in PMNs on a male patient confirmatory of? What about for females?

A

Neisseria gonorrhoeae (GC)
Direct Smear (diagnostic in males)
Presumptive in females…to
be confirmed

33
Q

How do you report/quantitate intracellular g-dc in PMNs?

A

Quantitate according to “direct smear” grading criteria, noting “intracellular”, example:
- PMN 4+
- Gram neg dc 4+ intra/extra cellular

34
Q

What are the main preliminary tests for N.gonorrhoeae?

A

Preliminary tests
screen with oxidase
gram stain

35
Q

How is N. gonorrhoeae phenotypically identified by?

A

N. gonorrhoeae:
phenotypically identified using cysteine trypticase agars or commercial systems such as API NH

36
Q

After the preliminary oxidase and gram stain tests, what other tests are done for N. gonorrhoeae?

A
  1. biochemical ID
  2. confirmation with serology, molecular or DFA (2nd method)

See ID flow chart on slide 23.

37
Q

How is susceptibility testing performed on N. gonorrhoeae?

A

Beta lactamase, AST requires specialized media - GC agar plus supplements 35-37C in CO2 (not done routinely, usually in ref. Lab)

38
Q

What condition is Treponema pallidum a causative agent of?

A

Causative agent of syphilis
helical shape major virulence factor.

Along with Borrelia and Leptospira: pathogenic Spirochetes

39
Q

What are the four stages of infection of syphilis?

A

4 stages of infection:
1. Primary stage “chancre” development, contagious stage
2. Secondary stage: fever, weight loss, malaise (flu-like).
Skin rash is typical & lymphadenopathy–> mild or unnoticed and symptoms disappear w/o treatment.
3. Latent (subclinical) stage= not inactive. Several decades to 30 years –> late latent stage:
Asymptomatic and noninfectious.
4. Tertiary stage: 10-25 years after Tissue destructive stage
Gummas (cancers)= granuloma-
like lesions (painless-noninfectious)
CNS disease (neurosyphilis)
Cardiovascular abnormalities
Eye disease

40
Q

How is diagnosis made for the primary stage on a syphilis specimen?

A

Diagnosis via wet mount motility
using “dark field” microscopy OR DFA-TP.

41
Q

What can be used to diagnose the latent stage on a syphilis specimen?

A

Serology can be used for diagnosis.

42
Q

What problems does congenital syphilis cause?

A

Congenital Syphilis:
1. Deafness-blindness-teeth issues
2. Bones issues
3. Neuro-syphilis/ death

43
Q

Describe the screening test for syphilis?

A

Screen test
1. Diagnosis via non-treponemal tests such as “VDRL” or “Rapid Plasma Reagin” (RPR).
2. Antigen is mixture of cardiolipin, cholesterol and lecithin.
3. Non-specific antibodies IgG/IgM are measured.

44
Q

When (what stage of syphilis) will the screening test might be negative when there is an infection and when is it most sensitive?

A

May be negative in primary stage.
Most sensitive in secondary stage.

45
Q

What could cause false positives for a syphilis test?

A

False positives might occur (viral
infections, auto-immune, pregnancy).

46
Q

What confirmatory tests can be done for syphilis?

A

Treponema pallidum

  1. Fluorescent Treponemal Antibody Absorption test (FTA-ABS). Note: Indirect more sensitive than DFA- Can be done in any stage-It is sensitive and specific
  2. Trepenema pallidum-Particle Antigen (TP-PA).
  3. Microhemagglutination assay
    (MHA-TP)
47
Q

Describe how the Fluorescent Treponemal Antibody Absorption test is done?

A
  1. Diluted serum is absorbed with Reiter treponemal culture (non-pathogen species)
    then serum is layered on slide containing T. pallidum antigen
  2. AB if present coats T.pallidium
    Fluorescein isothiocyanate labelled with antihuman globulin reacts with the patient’s IgG and IgM.
  3. Viewed with fluorescent microscope
48
Q

Describe how the Trepenema pallidum-Particle Antigen test is done.

A
  1. Microtitre wells contain diluted patient serum and colored gelatin particles sensitized with T. pallidum Ag
  2. Smooth mat forms when patient’s sera contains Abs
49
Q

How is Microhemagglutination assay (MHA-TP) different from Trepenema pallidum-Particle Antigen test?

A

Gelatin particles are replaced by sensitized red blood cells.

50
Q

What protozoa parasite causes vaginitis?

A

Trichomonas vaginalis

51
Q

What are the symptoms with a vaginal infection with Trichomonas vaginalis?

A

Symptoms include frothy, green discharge.

52
Q

Is Trichomonas vaginalis reportable to public health?

A

Non-reportable to public health.

53
Q

How does antigen detection work for Trichomonas vaginalis?

A

Antigen detection:
Color immunochromato-graphic technology if secretions contain Trichomonas proteins they bind with antibodies in buffering solution and embedded in a nitrocellulose dipstick.

See diagram on slide 32.

54
Q

How is Chlamydia trachomatis
described as a bacteria?

A

obligate intracellular bacteria

55
Q

What two forms does Chlamydia trachomatis exist in?

A

Exists in two forms:

  1. Elementary body (EB) for “survival” and initiation of infection.
  2. Reticulate body (RB) for multiplication.
56
Q

What clinical syndromes is Chlamydia trachomatis a causative agent for (serotypes D-K, serotypes A, B, Ba, & C, and serotypes L1, L2, & L3)?

A

Serotypes D-K
Genital (non-gonococcal urethritis, epididymitis, cervicitis,
salpingitis) and, eye infections

Serotypes A, B, Ba, C
“trachoma”

Serotypes L1, L2, L3
“lymphogranuloma venereum”

57
Q

How is Chlamydia trachomatis diagnosed?

A

fluorescent antibody

58
Q

Name some organisms responsible for non-STI of the genital region.

A
  1. Candida albicans
  2. Gardnerella vaginalis (bacterial vaginosis)
  3. Staphylococcus aureus
59
Q

What can cause an infectious condition with Candida albicans?

A

Candida albicans
Normal inhabitants of genital tract, but overgrowth causes vaginitis. Antibiotic therapy helps to grow Candida over the rest.

60
Q

What is the most common causative organism of vaginal candidiasis?

A

Candida albicans

61
Q

What is the colonial morphology of Candida albicans on blood agar?

A

Colonial morphology
pasty white, often “produce
“feet”

62
Q

What selective media is used for Candida albicans?

A
  1. Sabouraud Dextrose agar (SAB)
  2. Inhibitory Mold Agar (IMA), contains choramphenicol and gentamicin.

Note: IMA (good for isolation from specimens because of possible contamination)

63
Q

What is the principle of the germ tube test for Candida albicans?

A

In the presence of a high protein media, C. albicans produces filamentous extensions known as germ tubes with “no constriction at mother cell”.

64
Q

What does the flora in the vagina shift to in Bacterial vaginosis?

A

Shift from a predominance of Lactobacillus spp. to a mixture of Gardnerella vaginalis, Prevotella spp., Mobiluncus spp. and Mycoplasma hominis.

65
Q

What four criteria are used in which only 3 out of the 4 are required meet to be diagnosed with Bacteria vaginosis?

A

Preliminary diagnosis based on 3 out of 4 criteria meet:
1. “non-purulent discharge”=usually no PMN’s
2. PH (alkaline)
3. “whiff test”
(fishy odor)
4. Clue cells

66
Q

What is used for a definitive diagnosis for Bacteria vaginosis?

A

Definitive Diagnosis
- vaginal secretions are gram stained
- stains are read and scored according to Nugent’s scoring system

BV + (score 7-10)
BV = indeterminate (score 4-6)
BV - (score 0-3)

Review example slides 44-46.

67
Q

For what women are a gram stain results (Nugent scoring system) not reliable for BV?

A

Women >45 (postmenopausal) results might not agree with clinical symptoms (This is noted in the report to the Dr.)

Women >60 =GVAG rejected. Results are not reliable.

Microbiology 2 (22 decks)

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