Final

Question 1

What are the first clues to a physician to diagnose an infection?

Answer 1

Patient Medical history, family and social history, physical examination, signs and symptoms.

Question 2

Specimen’s are to be obtained from where?

Answer 2

The site of infection (Sites with normal microbiota, and sterile body sites)

Question 3

Proper labeling of samples should include…

Answer 3

patient name, medical record number, patient location, collection date and time, specimen type/source, test required and name of ordering physician

Question 4

Identification of Microbes often starts with (2)

Answer 4

Isolation and Visualization

Question 5

What is a limitation of determining morphology?

Answer 5

Morphology is media-dependent

Question 6

Complex Media

Answer 6

Support growth of most aerobic and facultative aerobic organisms

Question 7

Enriched media

Answer 7

contain specific growth factors enhancing the growth of certain bacteria

Question 8

Selective media

Answer 8

allow some organism to grow while inhibiting others

Question 9

Differential media

Answer 9

allow identification of organism based on their growth and appearance on the media

Question 10

Case Study - Rectal Abscess - Bacteroides fragilis (gram result and type)

Answer 10

Obligate anaerobic, gram-negative, rod-shaped bacterium

Question 11

Most pathogenic microbes can be detected in vitro in an overnight culture under aerobic conditions, except for …

Answer 11

Anaerobic bacteria
Slow-growing bacteria
Fastidious bacteria
Obligate intracellular bacteria

Question 12

Acidic dyes stain …

Answer 12

Alkaline structures

Question 13

Basic dyes stain …

Answer 13

acidic structures

Question 14

Simple stains are composed of

Answer 14

single basic dye

Question 15

Differential stains are used to …

Answer 15

distinguish between different cells, chemicals, or structures

Question 16

Common differential stains include:

Answer 16

gram-stain
acid-fast stain
endospore stain
histological stains

Question 17

Specials stains are used to identify

Answer 17

specific microbial structures

Question 18

Special stains include:

Answer 18

negative (capsule) stains
flagellar stains
fluorescent stains

Question 19

Chocolate agar -

Answer 19

extreme nutrient-rich media with lysed blood cells

Question 20

Blood agar -

Answer 20

rich medium

Question 21

Hektoen agar -

Answer 21

selective/differential media to recover gram-negative all-rounders

Question 22

What are the key ingredients to conduct a PCR?

Answer 22

DNA polymerase, primers, nucleotides, buffer and template

Question 23

When a direct detection of a pathogen is not possible, what may help with the diagnosis of acute infections?

Answer 23

Detection of specific antibodies or microbial antigens

Question 24

Immunological tests are …

Answer 24

culture-independent

Question 25

Direct Agglutination

Answer 25

antibodies react with antigens on cells or acellular particle such as viruses and form agglutinates

Question 26

Indirect agglutination (or latex fixation assay)

Answer 26

Antibodies or antigens are bound to latex beads forming larger agglutinates in presence of respective antigen or antibody

Question 27

Hemagglutination assay

Answer 27

patient’s serum can be directly used to detect a specific serum

Question 28

Enzyme-linked immunosorbent assays (ELISAs) use

Answer 28

antibodies to detect the presence of antigens or vice versa

Question 29

Direct ELISA

Answer 29

antigens are immobilized in the well of a microtiter plate

Question 30

Indirect ELISA

Answer 30

quantifies antigen-specific antibody rather than antigen

Question 31

3 characteristics of POC devices

Answer 31

speed, portability, convenience

Question 32

a good POC will have a high ________ and a high ________

Answer 32

Sensitivity; specificity

Question 33

5 methods of identification of microbes

Answer 33

Conventional techniques, biochemical methods based on semiautomatic and automatic systems, molecular-biological techniques, immunological techniques, and mass spectrometry (MS)-based semiautomatic methods

Question 34

Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry generates

Answer 34

organism specific mass spectral fingerprints; allows species identification in less than an hour

Question 35

Innate immunity

Answer 35

fast and non-specific; produces signal molecules

Question 36

Adaptive immunity

Answer 36

takes days and is highly specific; signal molecules from the innate immune system stimulate and direct adaptive immune responses

Question 37

Immunity is

Answer 37

the state of protection against foreign pathogens or substances (antigens)

Question 38

Dysfunctions of Immunity:

Answer 38

overly active or misdirected immune responses; and immunodeficiency

Question 39

immunodeficiency:

Answer 39

primary (genetic) loss of immune function or secondary (acquired) loss of immune function

Question 40

Innate immunity Physical defenses

Answer 40

physical barriers (mucous membrane) and mechanical defenses (shedding, mucociliary sweeping, flushing of urine or tears)

Question 41

Innate immunity chemical defenses

Answer 41

chemical mediators (tears, saliva, mucus, stomach acid), antimicrobial peptides, plasma protein and inflammation-eliciting mediators

Question 42

Epidermis

Answer 42

closely packed epithelial cells mainly keratinocytes

Question 43

Dermis

Answer 43

dense, irregular connective tissue with blood vessels, hair follicles, sweat glands