Lecture 14: Diagnosing Infections Flashcards

1
Q

True or False: When doing specimen collection, sufficient quantity is required

A

True

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2
Q

Swabs should be used for specimen collection from ___ and ____ _____ only

A

skin; mucous membrane

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3
Q

True or False: Decontamination procedures and appropriate handling should occur during specimen collection

A

True

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4
Q

True or False: Gram and acid-fast stains are an example of macroscopic direct testing

A

False - MICROSCOPIC, direct testing

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5
Q

____ ____ are both a culture/isolation test and direct test
A. AF Stain
B. Gram Stain
C. Gene probes

A

C. Gene probes

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6
Q

True or False: Antimicrobic sensitivity is an example of direct testing

A

False - culture/isolation

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7
Q

Gram stain, acid-fast stain, capsule stain, Fluorescent Ab stain, and gene probes are examples of:
A. Microscopic Direct Testing
B. Macroscopic Direct Testing

A

A. Microscopic Direct Testing
(example: syphilis)

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8
Q

Serological methods (agglutination) and PCR are examples of:
A. Microscopic Direct Testing
B. Macroscopic Direct Testing

A

B. Macroscopic Direct Testing

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9
Q

Advantage of Culture/Isolation specimen analysis?

A

Once you culture microorganism, you could do all kinds of testing (including direct!)

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10
Q

What are the 4 phenotypic methods of identification?

A
  1. Macroscopic
  2. Microscopic
  3. Biochemical
  4. Chemical Analysis
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11
Q

Strep tests, PPD, and western blots are example of ____ methods for identification while PCR, sequencing, and DNA hybridization are ____ methods

A

immunological; molecular

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12
Q

Which phenotypic method allows for the appearance of colonies, pigmentation, and phage typing?
A. Macroscopic
B. Microscopic
C. Biochemical
D. Chemical Analysis

A

A. Macroscopic

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13
Q

Label

A
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14
Q

Which types of cultures are best for determining number of bacteria in specimens?

A

Quantitative vs. semi-quantitative

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15
Q

Which phenotypic method could you use to see structural features of pathogens?

A

Electron microscope

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16
Q

Which phenotypic method uses enzymes, sensitivity to abx, or gas?
A. Biochemical
B. Chemical Analysis

A

A. Biochemical

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17
Q

True or False: Chemical Analysis allows for detect of chemical composition

A

True

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18
Q

What are the three types of selective media for isolation?

A

Thioglycolate
Chocolate agar
Charcoal agar

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19
Q

Which of the following selective media is best for growing B. pertussis (fastidious organism)?
A. Thioglycolate
B. Chocolate agar
C. Charcoal agar

A

C. Charcoal agar

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20
Q

Which media is best for Haemophilis (fastidious organism)?
A. Thioglycolate
B. Chocolate agar
C. Charcoal agar

A

B. Chocolate agar

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21
Q

If you add an abx to chocolate agar, you create Thayer-Martin media, which is selective for which pathogen?

A

Neisseria

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22
Q

Which media would be best for anaerobic bacteria (e.g Clostridium or Bacteroides)?
A. Thioglycolate
B. Chocolate agar
C. Charcoal agar

A

A. Thioglycolate

23
Q

When one is using a Thioglycolate media, broad spectrum ___ that acts against many ___ and ___ organisms is preferred.

A

abx; facultative/aerobic

24
Q

Why is selective media important with anaerobes?

A

Polymicrobic

25
Q

Which agar is the ONLY differential agar and is useful for differentiating between alpha or beta or gamma hemolysis group of bacteria?
A. Eosin Methylene Blue
B. MacConkey
C. Blood Agar

A

C. Blood Agar

26
Q

Which agar is best to determine the type of hemolysis of S. pyogenes and Streptococcus?
A. Eosin Methylene Blue
B. MacConkey
C. Blood Agar

A

C. Blood Agar

27
Q

True or False: Blood Agar can be used to differentiate between alpha, beta, and gamma hemolysis

A

True

28
Q

Label

A
29
Q

True or False: Eosin Methylene Blue and MacConkey are both selective and differential agars

A

True

30
Q

Which agar is best for differentiating between pink/red colonies for lactose fermenter, white/colorless for Gram (-) non, lactose fermenters?
A. Eosin Methylene Blue
B. MacConkey
C. Differential (Blood Agar)

A

A. Eosin Methylene Blue
B. MacConkey

31
Q

True or False: Only the blood agar selectively supports the growth of gram negative while inhibiting growth of gram positive

A

False - both EMB (Eosin Methylene Blue) and MacConkey do

32
Q

Label the EMB Agar

A
33
Q

Label the MacConkey Agar

A
34
Q

What is the best method for identification of species during outbreak?

A

Phage typing

35
Q

True or False: Different strains of bacteria differ in their susceptibility to different phages

A

True

36
Q

In vitro serological immunological methods involves in vitro diagnostic testing of serum, which allows for detection of…

A
  1. antibody from patient (qual/quan)
  2. microorganism’s antigen (qual)
37
Q

What is one of the cons of serology (immunological methods)?

A

Serological identification of an antibody to the infecting agent can only be successful several WEEKS after infection has occurred

38
Q

ELISA, RIA, Western blot, precipitation, agglutination are examples of which type of tests?
A. Molecular
B. Serological (Immunological)
C. Direct Test
B.

A

B. Serological (Immunological)

39
Q

Agglutination helps diagnose _____
A. Tetanus
B. Rosacea
C. Rubella
D. Tb

A

C. Rubella

  • detection of rubella virus antibodies in patient’s serum against solubilized rubella virus
40
Q

In a tube precipitation test, an ___ is put on the bottom and an ___ is on the top.
A. Antigen; Antibody
B. Antibody; Antigen
C. Anti-anti body; anti-antigen

What suggest a positive test?

A

B. antibody; antigen

  • Positive if there’s a band
41
Q

In the complement fixation test, no color change and no hemolysis suggests?
A. Negative reaction
B. Positive reaction

A

B. Positive reaction

  • Complement fixes Ab and RBC do not lyse
42
Q

In the complement fixation test, color change due to hemolysis suggets?
A. Negative reaction
B. Positive reaction

A

A. Negative reaction

  • Complement fixes RBC’s and hemolysis occurs
43
Q

Which test is good for screening, since it has HIGH sensitivity, but LOW specificity (can cause FALSE POSITIVE)?

A

ELISA

  • example: HIV dx
44
Q

True or False: Both indirect and direct ELISA detect Ab

A

False
- Direct ELISA: detect Ag
- Indirect ELISA: detect Ab

45
Q

Which tests can be initially used to dx HIV? Test used to confirm?

A

Initial - ELISA
Confirmation - Western Blot

46
Q

How is the western blot unlike the ELISA?

A

ELISA has low specificity while Western has high specificity

47
Q

Which test can be used to detect disorders in antibody production?

A

Immunoelectrophoresis

48
Q

True or False: PPD is an in vivo skin test while rapid tests are throat swabs (detect S. pyrogens antigen)

A

True

49
Q

True or False: Molecular methods of diagnostics (PCR, hybridization) are more rapid than phenotypic methods AND culturing not always needed

A

True

50
Q

Which test allows you to distinguish between different strains of a bacterial species AND used to determine source of outbreaks?
A. Hybridization
B. PCR
C. Culturing

A

B. PCR

51
Q

What test is useful for hybridizing LARGE NUMBER of DNA samples against LARGE NUMBER of DNA probes on a simple support membrane?

A

Checkerboard hybridization

52
Q

True or False: Checkerboard hybridization can be used to identify bacterial species contained in sample w/ many species

A

True

53
Q

____ ____ is the only media that is Differential
A. Chocolate Agar
B. Blood Agar
C. MacConkey or EMB

A

B. Blood Agar