Lab diagnosis RED WORDS

Question 1

pure cultures cultivated by?

Answer 1

cultivated and maintained via aseptic technique

Question 2

Describe aseptic technique

Answer 2

• sterilize loop via flame
• flaming tube tip to sterilize it (after uncapping it)
• only sterilized portion of loop touches tube
• tube tip reflamed
• tube recapped and loop resterilizes

Question 3

defined medium

Answer 3

chemically defined

Question 4

complex medium

Answer 4

chemically UNdefined

Question 5

colonies are isolated how?

Answer 5

Koch developed streak plate method to get visible, isolated masses

Question 6

What type of media is Eosin Methylene Blue Agar (EMB)

Answer 6

both selective and differential media

Question 7

What type of media is McConkey’s agar?

*+ or - results mean?

Answer 7

both selective and differential media

• often used to determine if a gastrointestinal microorganism that causes diarrhea is a pathogen
• *lactose negative= pathogen
• *lactose positive= non-pathogen

Question 8

Blood Agar?

Help ID?

Answer 8

• contains whole blood cells

* useful complex media for isolation and identification of pathogenic Streptococcus pyogenes that causes strep throat

Question 9

Chocolate Agar

Helps ID what bacteria?

Answer 9

• contains hemolyzed blood

* used for isolation of Neisseria meningitidis

Question 10

What type of media is Mannitol Salt Agar?

*types of staph found

Answer 10

• selective differential media
• often used to ID suspected Staph food poisoning BC only staph bacteria grows well in the high salt of this media
• -Staphylococcus aureus changes agar to YELLOW and is found in food
• -Staphylococcus epidermis not in food

Question 11

Broths

Answer 11

have all the necessary nutrients in a liquid form

Question 12

Agar media

Answer 12

have all the necessary nutrient in a gelled liquid

Question 13

What makes up Nutrient broth or Nutrient agar?

Answer 13

a non-defined (complex) media

**contains: water, dried beef-extract, peptone (soy beans), with or without agar

Question 14

Growth factors

Answer 14

specific substances such as Vitamins or Amino acids that are required by certain bacteria

Question 15

What are auxotrophs?

Answer 15

bacteria that require one or more growth factors

Question 16

Stains or staining

Answer 16

treatment of organisms with dyes to make them visible under microscopes

• reveals shape, size, internal and external structures
• may produce specific reactions to discriminate microbes

Question 17

Simple stain

Answer 17

is when a single reagent like methylene blue is used to see gross cellular morphology
•Simple and/or differential cell staining are used to increase contrast in brightfield microscopy.

Question 18

Differential stain

Answer 18

is when 2 or more stains are used
•Allows classification of bacteria based upon differences in stain uptake
•Simple and/or differential cell staining are used to increase contrast in brightfield microscopy.

Question 19

Steptococcus mutans is Gram positive or Gram negative?

Answer 19

Gram positive (purple)

Question 20

Porphyromonas gingivalis is Gram positive or Gram negative?

Answer 20

Gram negative (red)

Question 21

confocal scanning laser microscopy (CSLM)

Answer 21

is a form of light/fluorescent microscopy that allows for greater threedimensional imaging than other forms of light microscopy
–planes are visualized by adjusting the plane of focus of laser beam

Question 22

electron microscope

Answer 22

electrons are used instead of light rays

•Electron microscopes have far greater resolving power than light microscopes, with limits of resolution of about 0.2 nm

Question 23

transmission electron microscope

Answer 23

with thin sectioning the internal structures can be viewed

Question 24

scanning electron microscope

Answer 24

view the surfaces of microbes by coating with gold

Question 25

Seroconversion

Answer 25

occurs when antibody is produced in response to a primary infection

Question 26

Selective Media

Answer 26

a bacterial growth media that allows only certain species or strains of bacteria to grow -EMB agar only allows gram- bacteria to grow

Question 27

Differential Media

Answer 27

bacterial media in which certain bacteria that grow on these media take on unique colony characteristics -EMB agar E. coli colonies have a green sheen

Question 28

light microscope

Answer 28

ordinary visible light is beamed through a stained microbe

Question 29

phase contrast

Answer 29

dark image on lighted background- visualize live samples and avoid distortion from cell stains; image contrast is derived from the differential refractive index of cell structures versus background

Question 30

dark field

Answer 30

lighted image on dark background- Greater resolution can be obtained using dark-field microscopy, in which only the specimen itself is illuminated

Question 31

most widely used differential stain?

Answer 31

gram stain | *positive (purple) or negative (red)

Question 32

Acid fast stain differential stain is used to distinguish?

Answer 32

Mycobacterium tuberculosis | -difficult to stain bc mycolic acids present in cell wall

Question 33

Acid fast bacteria staining procedure? Color they turn?

Answer 33

``` retain the primary stain upon treatment with acid alcohol •1.Carbolfucsin (red) - primary stain •2.acid alcohol - decolorizer •3.methylene blue - counterstain ---•Acid Fast = Red ---•Non-Acid Fast = Blue ```

Question 34

Carbolfucsin (red) in acid fast stain

Answer 34

primary stain

Question 35

acid alcohol in acid fast stain

Answer 35

decolorizer

Question 36

methylene blue in acid fast stain

Answer 36

counterstain •Acid Fast = Red •Non-Acid Fast = Blue

Question 37

fluorescence microscope

Answer 37

1) all or parts of a microbe are tagged with a fluorescent molecule 2) the molecule is hit with a wavelength of light that will excite the fluorescent molecule 3) the excited molecule will then fluoresce and can be viewed against a dark background – oftentimes the fluorescent molecule is attached to an antibody that will recognized a specific type of molecule on the microbe

Question 38

direct vs indirect fluorescence microscope

Answer 38

* direct assay= antiviral antibody modified with a fluorescent/enzyme probe * indriect assay= using antiviral antibody and chemically modified anti-immunoglobulin