Biochemical Tests Flashcards
PEA: name, type, what
- Phenylethyl Alcohol
- Selective
- Selective for gram (-) by interfering with DNA synth. in gram (+) bacteria
Indicator for PEA?
None
(+) PEA test
Growth = gram (-) bacteria
EMB: name, type, what
- Eosin Methylene Blue
- Selective and Differential
- Selects for gram (-)
- Differential for coliforms
(+) EMB test (pink)
Gram (-) bacteria with coliforms
(+) EMB test (green)
Gram (-) bacteria E. coli with coliforms
(+) EMB test (white/colorless)
Gram (-), no coliforms
(-) EMB test
No growth, gram (+) bacteria
MSA: name, type, what
- Mannitol Salt Agar
- Selective and Differential
- Selects for Staphylococcus and Micrococcus species
- Differentiates for the ability to ferment mannitol
EMB indicator?
Eosin and Methylene Blue
MSA indicator?
Phenol Red
(+) MSA test (pink/red)
Non-pathogenic Staphylococcus or Micrococcus
(+) MSA test (yellow)
Pathogenic Staphylococcus or Micrococcus
Starch plate: type, what
- Differential
- tests for production of amylase
Starch plate indicator?
None
How does the the starch plate work?
The iodine and starch create a charge-transfer complex that makes the starch really dark. A clearing around the bacteria means the starch was broken down into glucose so there is nothing for iodine to bind to.
(+) Starch Plate Test
Clearing present after pouring iodine –> Amylase was produced
(-) Starch Plate Test
No clearing after pouring the iodine –> no Amylase was produced
OF Glucose: name, type, what
- Oxidative-Fermentative Glucose
- Differential
- Deferential for if bacteria can break down glucose through fermentation or oxidation
OF Glucose indicator?
Bromothymol Blue (pH dependent)
- glucose catabolized = acid release –> pH decreases
(+) OF Glucose Test for fermentation
Anaerobic tube = yellow
Aerobic tube = yellow
(+) OF Glucose Test for oxidation
Anaerobic tube = remains green
Aerobic tube = yellow at the top
(-) OF Glucose Test
Anaerobic tube = remains green
Aerobic tube = teal/blue, indicates ammonia byproduct from catabolized peptones, can’t use glucose
Fermentation Tubes: type, what
- Differential
- Differentiates if bacteria can catabolize a certain carbohydrate
Fermentation tube indicator?
Phenol Red; if fermented then acid is released and the pH goes down
Red fermentation tube…
(-), non-fermenter
Yellow fermentation tube…
(+), fermenter
Yellow fermentation tube with gas…
(+), true fermenter
Gelatin Hydrolysis: type, what
- Differential
- Determines if the bacteria can catabolize gelatin by using gelatinase
Gelatin Hydrolysis indicator?
None
(+) Gelatin hydrolysis Test
Gelatin liquifies
(-) Gelatin hydrolysis Test
Gelatin remains solid
Urease Test: type, what
- Differential
- determines if a bacteria produces urease
Urease Test indicator?
Phenol Red, if urease is produced, ammonia will be released and the pH increases
(+) Urease Test
Pink
(-) Urease Test
Remains the same color (orange)
Phenylalanine Slant: type, what, special
- Differential
- determines if bacteria can deaminate phenylalanine
- needs ferric acid to test results
Phenylalanine Slant indicator?
None
By-product of phenylalanine slant?
The removal of the amine group creates ammonia and creates phenylpyruvic acid as a byproduct
(+) Phenylalanine Slant
Green: ferric chloride reacted with the phenylpyruvic acid
(-) Phenylalanine Slant
Yellow: no phenylpyruvic acid was produced
MIO Deep: name, type, what, special
- Motility Indole Ornithine
- Differential
- Tests for motility, production of tryptophanase, and putrescine
needs Kovac’s reagent to see results