Chapter 15: Diagnosing Infections Flashcards

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1
Q

Light microscopy aids in the observation of these items.

A
  • cell shape, size, and arrangement;
  • Gram stain reaction, acid-fast reaction;
  • endospores, granules, and capsules
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2
Q

What can you use to pinpoint harder to see characteristics such as cell wall, flagella, pili, or fimbriae?

A

Electron Microscopy

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3
Q

Name the biochemical characteristics used to diagnose infectious agents. (5)

A
  1. (1) Enzyme production,
  2. (2) fermentation of sugars,
  3. (3) capacity to digest complex polymers,
  4. (4) production of gas,
  5. (5) sensitivity to antibiotics
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4
Q

Which method produces more rapid results?

A

Genotypic (automated)

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5
Q

Viable Noncultured (VNC)

A

microbes that can’t be grown in the laboratory that are identified by genotypic methods

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6
Q

Immunological Methods

A

patient sample is tested for the presence of specific antibodies to a suspected pathogen

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7
Q

A Gram stain of a sputum sample from a patient is an example of a ______ method of microbial identification.

A. genotypic

B. immunologic

C. phenotypic

D. histologic

E. None of the choices is correct.

A

A. phenotypic

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8
Q

“Clean Catch” Urine Sampling (describe the method)

A

taken by washing the external urethra and collecting the urine midstream

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9
Q

How to collect a skin sample

A

skin can be swabbed or scraped with a scalpel to expose deeper layers; wounds must be cleansed prior to swabbing

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10
Q

Sterile Material Sampling

A

blood, cerebrospinal fluid, and tissue fluids must be taken by STERILE NEEDLE ASPIRATION

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11
Q

Signs of microbial infections (4)

A
  • (1) fever,
  • (2) wound exudate,
  • (3) mucus production, and
  • (4) abnormal lesions
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12
Q

Presumptive Data

A

place the isolated microbe into a preliminary category

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13
Q

Confirmatory Data

A

pinpoint the microbe’s identity

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14
Q

Results are entered into ______

A

a summary patient chart

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15
Q

Tests involved when starting with patient analysis: (3)

A
  • (1) immunologic and serologic tests on blood;
  • (2) in vivo tests for reaction to microbe;
  • (3) clinical signs and symptoms
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16
Q

Direct Testing (Microscopic) (4)

A
  • (1) Gram-stain;
  • (2) Acid-fast stain;
  • (3) Fluorescent Ab stain;
  • (4) Gene probes
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17
Q

Direct Testing (Macroscopic) (2)

A
  • (1) Direct Antigen;
  • (2) Gene probes
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18
Q

Tests on Isolates (6)

A
  • (1) Biochemical;
  • (2) Serotyping;
  • (3) Antimicrobial Sensitivity;
  • (4) Gene probes;
  • (5) Phage testing;
  • (6) Animal inoculation
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19
Q

Care should be taken to avoid contamination with ______ when taking samples from a patient. air water droplet nuclei normal microbiota None of the choices is correct.

A

Normal Microbiota

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20
Q

Stains most often used when diagnosing

A

Gram-stain and Acid-fast

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21
Q

Specialized Media

A

used to enrich a pathogen present in small numbers or is easily overgrown

22
Q

Selective Media

A

to encourage the growth of only the suspected pathogen

23
Q

Differential Media

A

used to identify definitive characteristics and fermentation patterns

24
Q

pure cultures must be obtained from___________so that subsequent steps in identification will be accurate

A

isolation media

25
Q

Physiological reactions of bacteria to nutrients and other substrates indicates what?

A

Enzymes are present in bacteria

26
Q

Enzyme-mediated metabolic reactions often visualized by what?

A

a color change

27
Q

Carbohydrate Fermentation shows…?

A

production of acid and/or gas

28
Q

Enzyme actions (biochemical tests):

A

catalase, oxidase, and coagulase

29
Q

Dichotomous keys

A

Flow charts based on easily recognizable characteristics (motility, gram-stain, morphology) that helps identify bacteria

30
Q

Phage Typing

A

Test used when morphological and biochemical tests are insufficient; infects bacteria with bacteriophage to identify certain kinds

31
Q

Probes

A

small fragments of single-stranded DNA or RNA complementary to the specific DNA sequence of a particular microbe

32
Q

Fluorescent in situ hybridization (FISH)

A

rapidly identifies 16s RNA sequences without first culturing the organism;

33
Q

Ribosomal subunit suitable for identifying bacteria

A

16s rRNA (part of 30s)

34
Q

Polymerase Chain Reaction

A

Amplifies minute quantities of DNA in samples into billion of copies & greatly improving the quality of the test

35
Q

Kary Banks Mullis

A

Won a nobel prize for improving on the polymerase chain reaction

36
Q

Fluorescent in situ hybridization (FISH) requires a pure culture of organisms obtained from a patient sample. True False

A

False

37
Q

Serology

A

involves in vitro testing of serum based on the principle that antibodies have an extreme specificity for antigens

38
Q

Specificity

A

property of a test to focus only on a certain antibody or antigen, and not react with an unrelated or distantly related antigen

39
Q

Sensitivity

A

detection of even minute quantities of antibodies or antigens in a specimen;

40
Q

These samples can be analyzed for the presence of specific & sensitivity antibodies

A
  • urine,
  • cerebrospinal fluid,
  • whole tissues, and
  • saliva
41
Q

Fluorescent Antibodies (Direct)

A

unknown test specimen or antigen is fixed to a slide and exposed to a Fluorescent antibodies (Fab) solution;

42
Q

Antigen-Antibody (Ab-Ag)

A

Complexes that will remain bound to the Fab sample and will be visualized by fluorescence microscopy

43
Q

Fluorescent Antibodies testing is used to…? (Direct)

A

valuable for identifying and locating microbial antigens on cell surfaces or tissues; also ID’s agents for syphilis, gonorrhea, and meningitis

44
Q

Fluorescent Antibodies (Indirect)

A

In the indirect FAB method, known antigen is added to the test serum (not onto slide as direct method); binding of the antibody is seen under microscope

45
Q

Fluorescent Antibodies testing is used to…? (Indirect)

A

used to diagnose syphilis and various viral infections

46
Q

Radioimmunoassay (RIA)

A

antibodies or antigens labeled with a radioactive isotope used to pinpoint minute quantities of a corresponding antigen or antibody

47
Q

RIA is used to…?

A

used to detect hormone levels in samples and diagnose allergies

48
Q

Enzyme-Linked Immunosorbent Assay (ELISA)

A

uses an enzyme-linked indicator antibody to visualize Ag-Ab reactions

49
Q

ELISA is used to…?

A

common test used for antibody screening for HIV, hepatitis A and C, and Helicobacter

50
Q

Tuberculin test for Mycobacterium tuberculosis

A

small amount of purified protein derivative (PPD) from Mycobacterium tuberculosis is injected into the skin

51
Q

Indicator of mycobacterium tuberculosis

A

appearance of a red, raised, thickened lesion in 48 to 72 hours can indicate previous exposure to tuberculosis