Lecture 1 Overview

Question 0

What is the only indirect approach to microbial identification

Answer 0

Appearance of antibodies against the antigen

Question 1

Name the four direct methods of microbial identification

Answer 1

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

Question 2

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

Answer 2

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

Question 3

Define Opportunistic microorganisms

Answer 3

Are typically normal flora that can become pathogenic under certain circumstances

Question 4

Define “frank” or pathogenic microorganisms

Answer 4

Typically cause disease when present and are not generally normal flora

Question 5

Can the normal flora be helpful to the body? Explain

Answer 5

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

Question 6

What is the usual reason for opportunistic infections

Answer 6

Some impairment of the innate and/or adaptive immune systems

Question 7

Are viruses normally considered part of the normal microbial flora?

Answer 7

No.

Question 8

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

Answer 8

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.

Question 9

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

Answer 9

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

Question 10

What organism does Acid-Fast staining help visualize?

Answer 10

Mycobacterium

Question 11

What staining technique is used to visualize Capsules?

Answer 11

India Ink Stain

Question 12

What does a KOH prep visualize?

Answer 12

Fungi

Question 13

The purpose of PCR in visualization?

Answer 13

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

Question 14

What does the FITC Serology help us visualize?

Answer 14

Antibodies

Question 15

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

Answer 15

Genetic Analysis (PCR?)

Question 16

Describe how the KOH prep works

Answer 16

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.

Question 17

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

Answer 17

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

Question 18

What is the purpose of the enriched media?

Answer 18

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

Question 19

What does a selective media do

Answer 19

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

Question 20

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

Answer 20

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

Question 21

Name three ways to detect a virus from culture or colonization

Answer 21

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