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
