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Flashcards in Lecture 1 Overview Deck (22):
0

Name the four direct methods of microbial identification

1. Direct Microscopic Analysis
2. Microbial Culture, physiology, and morphology
3. Antigenic Analysis
4. Genetic Analysis

1

What is the only indirect approach to microbial identification

Appearance of antibodies against the antigen

2

Infectious microbial agents of disease can be divided into what three groups?

1. Normal Flora
2. Opportunistic
3. Pathogenic (Frank)

3

Define Opportunistic microorganisms

Are typically normal flora that can become pathogenic under certain circumstances

4

Define "frank" or pathogenic microorganisms

Typically cause disease when present and are not generally normal flora

5

Can the normal flora be helpful to the body? Explain

Yes, for example some normal flora can often out-compete frank pathogens, limiting their ability to colonize

6

What is the usual reason for opportunistic infections

Some impairment of the innate and/or adaptive immune systems

7

Are viruses normally considered part of the normal microbial flora?

No.

8

Explain the reasoning behind acute vs. convalescence in a clinical sample.

This is simply measuring the antibodies during the acute illness vs after the illness has either passed or is aged. The antibodies are different and usually indicative of the stage of the illness.

9

What are the 6 ways to prepare a bug to be visualized?

1. Gram Stain
2. Acid-fast stain
3. India Ink stain
4. KOH prep
5. FITC Serology
6. PCR (Polymerase Chain Reaction)

10

What organism does Acid-Fast staining help visualize?

Mycobacterium

11

What staining technique is used to visualize Capsules?

India Ink Stain

12

What does a KOH prep visualize?

Fungi

13

The purpose of PCR in visualization?

To help genetically identify sequences of DNA or RNA that helps determine the organism

14

What does the FITC Serology help us visualize?

Antibodies

15

Which method of microbial identification is most prone to operator error?

Genetic Analysis (PCR?)

16

Describe how the KOH prep works

Because Fungi are resistant to this staining, if fungi are present they will outlast the staining. If there is nothing left after the prep, there are no fungi present.

17

FITC serology is similar to what other type of test to determine antibodies?

ELISA test where a flourescent dye is added to the end of the antibody

18

What is the purpose of the enriched media?

If one is not sure what the bacteria is, this is an agar that makes sure the bacteria will grow so that it can be further tested. Blood agar is a good example of this type of media

19

What does a selective media do

It is specific to bacteria strains with specific nutrients and conditions for that specific bacteria to grow

20

Name 6 ways of identifying a microorganism after an in vitro isolation or culture

1. Microscopic visualization (gram stain, etc.)
2. Enzyme tests (catalase, oxidase, etc.)
3. Physiology (Metabolic pathways)
4. Ab detection (ELISA, FITC)
5. DNA/RNA characterization (PCR)
6. Antibiotic Susceptibility

21

Name three ways to detect a virus from culture or colonization

1. Cell lytic assay
2. DNA/RNA characterization
3. Ab detection