BIOCHEMICAL REACTIONS

Question 1

Enterobacteriaceae are called what

Answer 1

enterics

Question 2

what are the characteristics of colonies produced by Enterobacteriaceae in SBA and CHOC agar?

Answer 2

large, moist, gray colonies that can’t be distinguishable

Question 3

Large mucoid colonies are caused by what type of bacteria/s

Answer 3

Klebsiella and Enterobacter

Question 4

Beta hemolytic colonies are caused by what type of bacteria/s

Answer 4

Escherichia coli

Question 5

What are the primary isolation media used for isolating enterics

Answer 5

MacConkey (MAC)
Eosin-Methylene Blue (EMB)
Hektoen enteric agar (HEA)
Salmonella Shigella Agar (SSA)
Xylose-Lysine-Deoxycholate (XLD)

Question 6

This media can also be used to detect H2S production

Answer 6

Xylose-Lysine-Deoxycholate (XLD)

Question 7

All are CYTOCHROME OXIDASE NEGATIVE, except for

Answer 7

Plesiomonas species

Question 8

Most species are able to reduce nitrates to nitrites, except:

Answer 8

Erwinia and Pantoea agglomerans

Question 9

what bacterias are non-motile at 37C and 25C

Answer 9

Klebsiella
Shigella species
Yersinia pestis

Question 10

what bacterias are non-motile at 37C but motile
at 25C

Answer 10

Yersinia enterocolitica
Yersinia pseudotuberculosis

Question 11

able to utilize carbohydrates OXIDATIVELY (aerobic utilization)

Answer 11

oxidizers

Question 12

are unable to utilize carbohydrates even in the presence of oxygen (ASSACHAROLYTIC or NON-SACCHAROLYTIC)

Answer 12

non-oxidizers

Question 13

what algorithm does enteric and non-fermentative bacteria follow for laboratory isolation and detection

Answer 13

Specimen Accesioning and Evaluation
Direct Microscopy
Inoculation to primary isolation media

Question 14

what color of colony does lactose fermenter produce

Answer 14

pink

Question 15

if the bacteria is a lactose fermenter and has a presence of encapsulated bacteria what color and type of colony is produced

Answer 15

Pink colonies and mucoid colonies

Question 16

what color of colony does non-lactose fermenter produce

Answer 16

colorless colonies

Question 17

INOCULATION:
- TSI
- LIA
- MR
- VP
- SIM
- Citrate
- Urease

Answer 17

A. TSI – stab and streak
B. LIA – stab, streak, and stab
C. MR – emulsify colonies using loop or needle
D. VP - emulsify colonies using loop or needle
E. SIM- stab
F. Citrate- streak
G. Urease - streak

Question 18

orientation of TSI

Answer 18

butt/slant medium

Question 19

CHO content of TSI

Answer 19

(0.1%) Glucose
(1%) Lactose and Sucrose

Question 20

alternate source of energy in TSI

Answer 20

Peptone

Question 21

pH indicator of TSI

Answer 21

Phenol red

Question 22

source of sulfur for H2S production by bacteria (sulfur donor)

Answer 22

Sodium thiosulfate

Question 23

indicator for H2S

Answer 23

Ferrous sulfate

Question 24

TSI reaction of EKES

Answer 24

A/A, H2S-

Question 25

TSI reaction of SPC

Answer 25

A/A, H2S +

Question 26

TSI reaction of SPACEd

Answer 26

K/A, H2S+

Question 27

TSI reaction of YES PM

Answer 27

K/A, H2S-

Question 28

Principle pf LIA

Answer 28

Determine the ability of organisms to deaminate or decarboxylase lysine and produce H2S gas

Question 28

TSI reaction of Non-fermentative organisms

Answer 28

K/K

Question 29

bacterias that are deaminase +

Answer 29

Proteus Providencia Morganella

Question 30

orientaion of LIA

Answer 30

slant/butt

Question 31

serves as the substrate for the decarboxylase or deaminase enzyme of bacteria.

Answer 31

lysine

Question 31

the fermentable sugar that provides acidity to the medium after fermentation by bacteria

Answer 31

1% Glucose

Question 32

pH indicator of LIA

Answer 32

bromcresol purple

Question 33

Principle of Methyl Red and Voges-Proskauer test

Answer 33

Glucose degradation in the Embden-Meyerhoff pathway produce pyruvic acid as byproduct.

Question 34

products of MR and VP test

Answer 34

MR - mixed acids VP - diacetyl

Question 34

detects mixed acids produced from pyruvic acid after its further degradation by bacteria though the mixed acids pathway

Answer 34

methyl red test

Question 34

detects diacetyl as a product of the oxidation of acetoin which is a byproduct produced from pyruvic acid after its further degradation by bacteria through the butylene glycol pathway.

Answer 34

VOGES-PROSKAUER TEST

Question 35

neutral pathway produces that color

Answer 35

pink

Question 35

acidic pathway produces that color

Answer 35

red

Question 36

It is a semi-solid medium that facilitates bacterial motility

Answer 36

Sulfide Indole Motility (SIM) test

Question 37

– enters the bacterial cell’s metabolic pathway for the production of energy

Answer 37

Pyruvate

Question 37

pH indicator of CITRATE

Answer 37

Bromthymol blue

Question 37

Principle of Urease test

Answer 37

Urease splits the urea molecule into NH3, CO2, and H2O. Ammonia reacts in the solution to form an alkaline compound, ammonium carbonate, which results in an increased pH of the medium and a color in the indicator to pink-red.

Question 37

original color of urease

Answer 37

yellow

Question 37

Principle of Citrate

Answer 37

Some organisms can utilize SODIUM CITRATE as their sole source of carbon producing acetate and other alkaline carbonate end products in the process. These product change the color of the indicator from green to blue.

Question 37

SIM H2S indicator forming a black precipitate

Answer 37

ferrous ammonium sulfate

Question 37

the only carbon source of CITRATE

Answer 37

Sodium citrate

Question 37

pH indicator of urease

Answer 37

phenol red

Question 37

RAPID UREASE PRODUCERS (w/in 2-4 hours)

Answer 37

Proteus Providencia Morganella

Question 38

WEAK UREASE PRODUCERS within 4 hours

Answer 38

Citrobacter Klebsiella Enterobacter Yersinia Seratia

Question 38

Used to study CHO utilization by non-fermenters.

Answer 38

Oxidation/Fermentation (OF) Test

Question 38

Principle of Nitrate reduction test

Answer 38

Some organisms possess nitrate reductase that can reduce nitrate (NO3−) to nitrite (NO2−)

Question 38

break down of gelatin to amino acid

Answer 38

Gelatin hydrolysis

Question 38

What species are the only genera positive for Phenylalanine deaminase.

Answer 38

Proteus, Providencia, Morganella

Question 38

what bacteria is present if the gelatin hydrolysis test is positive

Answer 38

Serratia species

Question 38

pH indicator of OF test

Answer 38

Bromthymol blue