Tests Flashcards
1
Q
- add a drop of hydrogen peroxide to dry smear of bacteria
- positive if bubbles form
- negative if no bubbles, delayed bubbles, or weak bubbles
- aerobic bacteria positive (exception is microaerophiles)
A
Catalase Test
2
Q
- small disk
- tests for the presence of cytochrome —- in electrone transport chain
- positive = blue/maroon, oxidized
- negative = colorless, reduced
A
Oxidase Test
3
Q
- differential media based on ability to ferment specific carbohydrates
- positive = yellow, production of acid
- negative = orange/red/hot pink, basic
- also contains peptone and beef extract
- 24 hours
- durham tube inside, bubbles = carbon dioxide
A
Phenol red carbohydrate broth
4
Q
- in the anaerobic respiration category, testing for nitrate and nitrite reductase
- if red after 48 hours, nitrate reductase positive
- add zinc, if red after, negative for nitrate and nitrite reductase
- if colorless after both, nitrate and nitrite reductase positive
- reagents nitrate A and nitrate B
A
Nitrate reduction using nitrate broth
5
Q
- selective and differential medium for gram negative rods that are either lactose fermenters or non-lactose fermenters
- pink/dark red colonies positive for lactose fermentation
- clear colonies
- also contains peptones and beef extract
- zone of precipitated bile salts = strong lactose fermenter
- contains neutral red
A
MacConkey Agar
6
Q
- Selective media that inhibits the growth of Gram negative organisms
- contains 0.25% phenylethyl alcohol
- most useful for isolation from G- because some may still grow
A
PEA Agar
7
Q
- contains TSA and sheep red blood cells
- all purpose and differential
- determines whether organisms can hemolyze/lyse red blood cells
A
Blood Agar
8
Q
- the complete hemolysis of red blood cells
- zone of clearing around colonies
A
Beta hemolysis
9
Q
- incomplete hemolysis of red blood cells
- no zone of clearing, brown/greenish agar
A
Alpha Hemolysis
10
Q
- inability to perform hemolysis
- growth with no change to the agar
A
Gamma hemolysis
11
Q
- selective and differential
- isolates pseudomonas aeruginosa
- tests for production of pyocyanin (blue-green pigment, water soluble)
- contains cetrimide (which inhibits other pseudomonas species)
A
Pseudosel Agar
12
Q
- all-purpose differential media based on bacteria’s ability to produce fluorescein
- contains magnesium and potassium salts
- results should be looked at under UV light
A
Pseudomonas Agar F
13
Q
- used to differentiate and identify enteric (intestinal) bacteria
- coliforms = gram negative rods, ferment lactose, produce gas, facultative anaerobes, do not produce spores
- determine whether they are fecal coliforms or not
A
IMViC Tests
14
Q
- test production of the enzyme tryptophanase (use tryptophan as carbon source and produce —)
- tryptone broth used
- 48 hour incubation
- Kovac’s reagent
- positive result = red ring around top of broth
- negative result = no color change
A
Indole Test
15
Q
- determines if bacteria ferments glucose through pathway that produces mixed acids
- uses —- — indicator
- positive result: red/dark orange
- negative result: yellowish orange
- uses MRVP broth
A
Methyl Red Test
16
Q
- determines if bacteria ferment glucose through the pathway that produces diacetyl
- MRVP broth
- positive result when there is a red layer in the upper section of the broth
- negative when there is no color change or green/copper color
- Barritt’s A and Barritt’s B reagents used
A
Voges-Proskauer Test
17
Q
- Simmon’s — agar
- contains bromthymol blue
- used to determine if bacterium can ferment —-
- 48 hours
- positive is blue with growth, produces alkaline products
- negative no growth and green slant
A
Citrate Test
18
Q
- determine if lysine and ornithine decarboxylase
- LDC and ODC broth, contains glucose
- bromcresol purple
- covered in mineral oil to maintain anaerobic conditions
- purple growth = positive (basic), yellow growth = negative (acidic)
A
LDC/ODC Test
19
Q
- determines whether a bacteria can ferment glucose/lactose and produce CO2/H2S gas
- contains phenol red
- stab butt of the tube
- butt yellow, ferments glucose
- butt and slant yellow, ferments lactose and glucose
- bright pink neither glucose or lactose
- black butt = H2S gas
- 24 hours
- carbon dioxide if clear space
A
KIA Agar
20
Q
- living bacterial cell takes up free piece of DNA from environment or from dead bacterial cell
A
Transformation
21
Q
- When one cell is the donor cell, F+ (containing sex pilus)
- One cell is the recipient cell (F-)
- Direct contact
A
Conjugation
22
Q
- requires bacteriophage for the exchange of genetic material
- generalized = portion of bacterial genome accidentally incorporated, coming from any part of bacterial genome
- specialized = specific portion of DNA incorporated
A
Transduction
23
Q
- detect presence of antigen in a sample
A
Direct ELISA
24
Q
- detect presence of antibody in sample
A
Indirect ELISA
25
- when an antibody coats surface, binds antigen in sample, antibody with color changing binding capabilities binds
- antibodies from two different animals (so does not recognize as "self")
Sandwich/Antigen Capture ELISA
26
Antibody captured between antibody bound to surface and antigen
Antibody Capture ELISA
27
- 0.1mL added to each well
- Endpoint dilution is 1/128
- Calculate titer
1/128*0.1 = 1/1280
28
underlined wells
boxed wells
all other wells
- read in groups of 3 (1,2,4 for total of 7)
underfill to add mineral oil and make anaerobic
boxed wells fill all the way up
regular
- API test strip
29
CFU = original sample*dilution*volume
How to calculate dilution problems
30
- crystal violet primary stain
- gram's iodine (binds)
- decolorizer
- safranin (pink) counterstain
Gram Stain
31
- test for waxy, mycolic acid layer
- primary stain carbol fuchsin (hot pink/red)
- heat
- decolorized with acid alcohol mix
- methylene blue secondary stain (blue)
positive = pink/red
Acid Fast Stain
32
- primary stain malachite green
- heat
- decolorized with water
- safranin secondary stain
positive green inside pink
Endospore Stain
