Med Bac Lab Final

Front 1

Traits of Enterobacteriacae

Back 1

Gram Negative
Bacilli
Non-spore forming
Non-fastidious
Grow on MacConkey
Ferment Glucose
Some gas production
Most frequent in clinical microbiology
Inhabit GI tract
Ubiquitous in soil, water, and plants.

All ferment glucose
All reduce nitrates to nitrites
All oxidase negative
All are motile with exception of:
Klebsiella
Shigella
and Yersinia

Front 2

MacConkey Agar's is

Back 2

both selective and differential.

Front 3

MacConkey's selective ingredients and what they inhibit

Back 3

crystal violet - inhibits Gram positives

bile salts - inhibits growth of most non-gut organisims

Front 4

MacConkey's differential ingredients

Back 4

neutral red - stains colonies that ferment lactose
lactose - there to provide pH shift

Front 5

Eosine methylene blue agar is

Back 5

selective for Gram negative (inhibits Gram positives)

differential for E. coli which gives a metallic green sheen and differential for lactose fermenters which display a colony with a dark center
a blend of eosin and methylene blue

Front 6

DNase is used for

Back 6

identifying microorganisms based on deoxyribonuclease(DNase) activity.

Front 7

DNase uses ____ as a colorimetric indicator.

Back 7

methyl green - combines with depolymerized DNA at pH 7.5 creating a clear zone.

Front 8

Triple Sugar Iron (TSI) is used to

Back 8

differentiating gram negative enteric bacilli on fermentation of glucose, lactose, and sucrose, and on hydrogen sulfide production, and hydrogen gas and CO2 gas production.

Front 9

TSI sugar fermentation is indicated by _____
and H2S by ______

Back 9

phenol red indicator
pH<7 turns it yellow
pH>7 turns it red

ferric ions
ferric ions and H2S make ferrous sulfafe (black precipitate)

Front 10

Citrate test determines

Back 10

if organism can utilize citrate as sole source of carbon.

Essentially tests for citrate permease.

positive is blue
negative is green

Front 11

Citrate test uses ____ as an indicator

Back 11

bromothymol blue indicator

Front 12

SIM test stands for

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Hydrogen sulfide, Indol, Motility Test Medium

Front 13

SIM indole is used to

Back 13

determine if the organism cleave indole from tryptophan.

Essentially it tests for tryptophanase.

Front 14

SIM reagent to test for Indole

Back 14

Kovac's solution.

positive - red ring
negative - no color change

Front 15

MR-VP stands for

Back 15

Methyl Red and Voges-Proskauer test

Front 16

MR-VP indicator for low pH is

Back 16

methyl red

positive - red
negtive - orange/yellow

low pH indicates pyruvate was utilized by mixed acid pathway

Front 17

MR-VP indicator for high pH is

Back 17

Barritt's solution A (alpha naphthol)
and Barritt's solution B (KOH)

positive - reddish to black
negative - no color change

positive indicates presence of 2,3-Butanediol and ethanol from fermentation of glucose
And acetoin

Front 18

Urea test determines if

Back 18

organism contains the urease enzyme

positive - intense red
negative - no color change

Front 19

Urea uses the indicator

Back 19

phenol red that turns red at pH 8.1

Front 20

Lysine decarboxylase is used to determine if

Back 20

the organism have the enzyme lysine decarboxylase used to decarboxylase the amino acid lysine.

Front 21

Lysine decarboxylase uses _____ as the fermentable sugar and the pH indicator _______.

Back 21

glucose
brom cresol purple
cresol red

positive - no color change (purple->yellow->purple).
negative - yellow

Front 22

Phenylalanine deaminase test is used to

Back 22

see the deamination of phenylalanine to phenylpyruvic acid by enzymatic activity.

Front 23

The phenylalanine deaminase test uses ________ as the reagent.

Back 23

ferric chloride.

The ferric chloride chelate the phenylpyruvic acid and form a green color.

positive - dark green
negative - no color change

Front 24

Mannitol Salt Agar is selective for

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Staphylococcus

Front 25

MSA uses the inhibitor _____
MSA uses the indicator _____

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NaCl at 7.5%

Phenol Red

Front 26

MacConkey +MUG.

MUG is...

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methylumbelliferine + UV

E. coli with glucoronidase enzyme fluoresce under UV light

Front 27

Causes typhoid fever

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Salmonella typhi

Front 28

Biochemical features of Salmonella

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-in almost every case, they do not ferment lactose
-they are negative for indole, Voges-Proskauer, phenylalanine, and urease.
-most produce hydrogen sulfide on TSI.

Front 29

Characteristics of Salmonella

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-Gram negative
-Rods
-Glucose fermenters
-oxidase negative

Front 30

SS agar stands for ___
Does ____

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Salmonella-Shigella agar

Salmonella shows up as black colonies
Shigella shows up as clear colonies
Coliforms produce pink colonies

Front 31

SS agar inhibitor

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bile salts
Brilliant green

inhibits gram positive and most coliforms

Front 32

SS agar indicator

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Neutral Red
Brilliant green are pH indicators

Sodium thiosulfate and ferric citrate are indicators of H2S

Front 33

Hecktoen Enteric Agar does

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Salmonella has black colonies
Shigella has clear colonies

Front 34

Hecktoen Enteric Agar inhibitor

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bile salts and dyes (brom thymol blue and acid fushsin)
Brilliant green

inhibits gram positive and most coliforms

Front 35

Hecktoen Enteric Agar indicator

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Bile salts
H2S indicator

Front 36

Selenite-F broth does

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inhibits Gram positive and many Gram negative. Enriched for Salmonella and Shigella

Used to grow, then sub-plate if no growth on SS agar and Hecktoen Enteric agar

Front 37

Selenite-F broth inhibitor

Back 37

Sodium Selenite

Front 38

Non-fermenting Gram negative bacilli

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Pseudomonads

Front 39

Pseudomonads characteristics

Back 39

aerobic
non-spore forming
gram negative
rods
motile with polar tuft flagella
oxidase positive
use O2 as final electron acceptor
some can grow in anaerobic conditions by using nitrogen as final electron acceptor
moist environments

Front 40

Pseudomonas aeruginosa

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virulence factors

elaborates both PSF and PSP

Front 41

Pseudomonas isolation agar selective agents

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cetrimide, adetamide, nitrofurantoin

big one is IRGASAN, a potent broad spectrum antibiotic

Front 42

PSF is

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Pseudomonas Agar F

Front 43

Pseudomonas Agar F enhances production of _____ and inhibits production of _____.

Back 43

fluorescein

pyocyanin

Front 44

PSP is

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Pseudomonas Agar P

Front 45

Pseudomonas Agar F enhances production of ____.

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pyocyanin

Front 46

Pseudomonas bad because

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resistant to many antibiotics
especially bad for cystic fibrosis patients

Front 47

Organism positive for Gelatin hydrolysis

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P. fluorescens

Front 48

O/F tests

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positive - yellow
negative - green
blue is from peptones
oil used to make anaerobic

Front 49

Uncommon Gram negatives studied

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Vibrio
Aeromonas
Plesiomonas
Acinetobacter