lab 14-15-18

Question 1

how many units of TaxoA (bacitracin) is placed on the agar plate?

Answer 1

0.04 units

Question 2

incubation temp and period Bacitracin for STAPH

Answer 2

18-24hr at 35-37C in ambient air

Question 3

Bacitracin for STREP differentiation requirements

Answer 3

5-10% CO2

Question 4

ZOI size for (+) bacitracin sus

Answer 4

> 10mm

Question 5

Bile Esculin Test for what?

Answer 5

differentiate enterococci and group D streptococci,

Question 6

inhibitory agent in bile esculin test

Answer 6

4% Bile salts

Gram-positive bacteria other than some streptococci and enterococci are inhibited by the bile salts in this medium. Organisms capable of growth in the presence of 4% bile and able to hydrolyze esculin to esculetin.

Esculetin reacts with Fe3+ and forms a dark brown to black precipitate.

Question 7

Esculetin reacts with ____ and forms a dark brown to black precipitate.

Answer 7

Fe3+

(+): Enterococcus faecalis
(-): Streptococcus pyogenes

Question 8

catalase can what?

Answer 8

degrade hydrogen peroxide to water and oxygen

Question 9

coagulase will react directly with??

Answer 9

fibrinogen

Question 10

Side note:

The clotting mechanism involves activation of a plasma coagulase-reacting factor (CRF), which is a modified or derived thrombin molecule, to form a coagulase-CRF complex. This complex in turn reacts with fibrinogen to produce the fibrin clot

Answer 10

muah

Question 11

tube coagulase test

-incubate for how long?

Answer 11

35-37c in ambient air for 4hrs

Question 12

the degradation product from metabolism of TRYPTOPHAN

Answer 12

Indole

Question 13

Indole test medium

Answer 13

Tryptophan test medium

Question 14

indole test reagent?

Answer 14

observe for red color after adding

Kovac’s reagent containing
p-dimethylaminobenzaldehyde

dim-ethyl-amino-benzal-dehyde

Question 15

positive for indole?

Answer 15

Pink to wine-colored ring

negative: no color change

Question 16

Bacteria (+) and (-) for indole

Answer 16

(+): E. coli
(-): Klebsiella pneumoniae

Question 17

test to observe mixed acid fermentation route

Answer 17

Methyl Red Test

Question 18

MR pH acid color breakpoint?

Answer 18

(+) pH: 4.4 = bright red color

weakly (+): Red-orange color

(-): Yellow colorn

Question 19

VP test detects the formation of ?

Answer 19

acethyl methyl carbinol (ACETOIN)

as a product of glucose fermentation

Question 20

Side note:

Acetoin is formed as a product of an alternative pathway of glucose fermentation utilized by some species of Enterobacteriacee.

Answer 20

Magandang gabi, baby.

Question 21

VP reagents

Answer 21

6-8 drops of 5% alpha napthol

4 drops of 40% potassium hydroxide

Question 22

Bacteria
VP pos and neg

Answer 22

Pos: K. pneumoniae
Neg: e coli

Question 23

citrate test postive color indicator?

Answer 23

Bromthymol blue — from green to blue

Question 24

Bacteria:

Citrate pos and neg

Answer 24

Pos: Enterobacter aerogenes
Neg: E. coli

Question 25

The only members of enterobacteriaceae that are deaminase positive?

Answer 25

PPM

-proteus
-providencia
-morganella

Question 25

LIA useful for identification of what bacterias?

Answer 25

SPPM

-Salmonella
-Proteus
-Providencia
-Morganella

Question 26

when is cadaverine formed?

Answer 26

When the organism produces lysine decarboxylase

Question 27

what forms the burgundy color on the slant of LIA?

2pts

Answer 27

1. ferric ammonium citrate
2. flavin mononucleotide

Question 28

pH indicator of LIA

Answer 28

bromocresol purple

yellow at or below pH 5.2
purple above pH 6.8

Question 29

Interpret the results LIA:

K/K
K/A
R/A

Answer 29

K/K - lysine decarboxylation (cadaverine is formed)

K/A -glucose fermentation
R/A - lysine deamination

Question 29

side note:

Sodium thiosulfate in the presence of Ferric ammonium citrate will produce black precipitates

Answer 29

magandang gabi, baby.

Question 29

motility semi-solid agar concentration?

Answer 29

0.4% or less to permit the organism to spread freely.

Question 29

side note:

a. Alkaline slant and butt: H2S positive: Citrobacter freundi
b. Alkaline slant and butt: Escherichia coli
c. Alkaline slant and butt: H25 positive: Salmonella typhimurium
d. Red slant, acid butt: Proteus mirabilis

Answer 29

~

Question 30

optochin interferes with??

Answer 30

ATPase and the production of ATP

Question 30

TaxoP ZOI mm susceptible on sheep blood agar

Answer 30

14-16 mm

Question 31

interpret the results TaxoP

1. 17mm
2. 13 mm

Answer 31

1. sus
2. resistant

Question 32

test to differentiate members of enterobacteriaceae from other gram neg-rods.

Answer 32

TSI

Question 33

TSI pH indicator

Answer 33

Phenol Red

Question 34

serves as the indicators of acidification and H2S production of in TSI
(2)

Answer 34

1. phenol red
2. ferrous sulfate

Question 35

test medium for salt tolerance test

-indicators or acid prodcution

Answer 35

heart infusion broth with 6.5% NaCl

-glucose and bromocresol purple

Question 36

(+)
(-)
for salt tolerance test

Answer 36

(+) Visible turbidity in the broth, with or without a color change from purple to yellow.

(-) No turbidity and no color change (yellow color)

Question 37

medium for urea test

results:
pos
neg

Answer 37

Christensen urea medium / urea test broth

(+) Change in color of slant or throughout the medium from light orange to magenta or pink

(-) No color change (agar slant and butt or broth remain light orange)