Media

Question 1

Phenyl ethyl alcohol

Answer 1

suppresses Gram - growth

Question 2

Columbia CNA with 5%sheep blood

Answer 2

Differential and selective media that Promotes Gram + cocci growth
Alpha- partial hemolysis
Beta- Complete hemolysis
Gamma- no hemolysis

Question 3

Bile Esculin test

Answer 3

Selective and differential test to separate Streptococcus bovis
Most organisms cannot survive in bile and hydrolyze esculin at the same time

Question 4

Mannitol Salt Agar

Answer 4

Useful in identification of Staphylococcus Aureus
7.5% Na serves as the selective part of the media- produces a concentration gradient too high more most organisms
Yellow halo indicates positive for mannitol fermentation

Question 5

MacConkey Agar

Answer 5

CV and Bile is the selective agent that prevents growth of gram + cocci
Lactose is the differential test.
Lactose + is indicated by pink growth

Question 6

Eosin Methylene Blue agar

Answer 6

Selective for Gram -
Pink and mucoid- ferments lactose with little acid production
Dark, with or without metallic sheen- ferments lactose and or sucrose with acid production
Colorless- Gram - that does not ferment lactose or sucrose

Question 7

Hektoen Enteric

Answer 7

Used to isolate Salmonella and shigella
Pink to orange- produces acid not sal. or shi
Blue green with black precipitate- no lactose fermentation but Sulfur reduction to H2S - indicates salmonella
Blue green without Black precipitate- No lactose fermentation or sulfur reduction- possible salmonella or shigella

Question 8

XLD agar

Answer 8

Selective and differenital test used to isolate and identify shigella and providencia
Contains desoxycholate to inhibit gram positive growth
Fermentation of xylose produces yellow clearing

Question 9

Oxidation fermentation [sealed]

Answer 9

green/blue- oxidation
yellow throughout- both or fermentation only
slight yellow on top- both or slow fermination
green- no sugar metabolism-organism is nonsaccharolytic

Question 10

Oxidation fermentation [unsealed]

Answer 10

any yellow-oxidation
yellow throughout- both or ferm. only
slight yello on top- both or slow ferm
green or blue- no sugar met. organism is nonsaccharolytic

Question 11

Phenol Red Broth

Answer 11

Test organisms ability to ferment specific carbohydrates through detection of acid production

Yellow- ferm. by acid production
red- no acid production

Question 12

MR-VP

Answer 12

MR: red- mixed acid NC-no acid
VP: red: butanedoil ferm (acetoin prod)
NC: butanedoil ferm. (no acetoin prod)

Question 13

Catalase

Answer 13

Simple test designed to detect presence of catalase- an enzyme that breaks down H2O2 to water and H
Indicated by the presence of bubbles

Question 14

Oxidase

Answer 14

Test for the presence of Cytochrome C oxidase- an enzyme that is present within a cells electron transport chain
Test is conducted with a chemical that produces purple color once oxidized

Question 15

Nitrate Reduction

Answer 15

review
Red the first time- reduces nitrate to nitrite
Red the second time- does not reduce

Question 16

Citrate test

Answer 16

Defined test the detects organisms ability to utilize citrate as the sole carbon source
Blue color or growth- Citrate is utilized
No growth- citrate is not utilized

Question 17

Decarboxylation

Answer 17

Test that detects the decarboxylation of specific amino acids added to broth under anaerobic conditions
Purple- indicates positive decarboxylation
Yellow- indicates glucose fermentation

Question 18

Phenylalanine Deaminase

Answer 18

Test that indicates organisms ability to deaminate phenylalanine
Edition of reagents allows for detection of deamination
Green color- Phenylalanine deaminase is present
No color change- no phenylalanine deaminase present

Question 19

Starch hydrolysis

Answer 19

Agar plate that is fortified with starch
Organism is allowed to grow on the plate and gram iodine is placed on the plate to detect for clearing of starch around the colonies

Question 20

Urea

Answer 20

Tests organisms ability to produce urease

Pink=positive

Question 21

Casein Hydrolysis Test

Answer 21

Test for the ability of an organism to hydrolyze the milk enzyme casein
Clearing around the colony indicates a positive test

Question 22

Gelatin Hydrolysis

Answer 22

Test for the ability to hydrolyze gelatin with the enzyme gelatinase
Gelatin is liquefied- indicates that an organism is positive for gelatinase

Question 23

DNA hydrolysis test

Answer 23

Agar plate that contains DNA fragments to test for an organisms ability to depolymerize DNA with deoxyribonuclease
Indicated positive by clearing around colonies

Question 24

Lipid hydrolysis

Answer 24

Test for the presence of Lipase in an organism
Indication by clearing around colony
Tests include tributyrin agar or Spirit Blue agar

Question 25

SIM

Answer 25

Three part test
Motility -marked by growth radiating from stab (may be hidden if sulfur reducing)
Sulfur reduction- media will turn black if H2S is reduced
Indole- Kovacs reagent is added to test for indole production
Indicated by pink/red color in reagent

Question 26

Triple Sugar Iron/Kligler agar

Answer 26

Multi component test that indicates, glucose, lactose and sucrose fermentation, as well as H2S production and gas production

Question 27

Litmus Milk medium

Answer 27

review

Question 28

PYR

Answer 28

Tests for Group A streptococci and Enterococci that produce the enzyme L-pyrolidonyl Arylamidase
Test organism is inoculated on a pyr disk and p-dimehtylaminocinnamaldehyde soution is applied
Within 5 minutes if the disk turns red it is positive.

Question 29

Lysine Iron Agar

Answer 29

Test the ability of enterics to deaminate and decarboxylate lysine and for production of hydrogen sulfide