Biochemical ID

Question 1

Phenylalanine deaminase will turn the tube what color when positive?

Answer 1

Yellow

Question 2

What organisms are phenylalanine deaminase positive?

Answer 2

Proteus, Providencia, Morganella

Question 3

The mixed acid fermentation process will result in lots of ______ (gas/acid) production. What test is this?

Answer 3

Acid; Methyl red

Question 4

The butylene glycol fermentation pathway results in lots of _____ (gas/acid) production. What test is this?

Answer 4

CO2 gas; Voges-Proskauer

Question 5

What does the Voges-Proskauer test test for?

Answer 5

The ability of bacteria to ferment glucose to the non-acid product butanediol

Question 6

What is the VP reaction?

Answer 6

glucose → [acetoin] → butanediol VP

Question 7

What is the indicator for VP test?

Answer 7

40% KOH and α-naphthol

Question 8

What will the TSI rxn be for Shigella?

Answer 8

K/A (Alk/A) – does NOT ferment sucrose

Question 9

What will the TSI rxn be for Salmonella?

Answer 9

K/A – Does NOT ferment sucrose

Question 10

1) What will the TSI rxn be for Yersinia?
2) What will the KIA rxn be for Yersinia?
Why?

Answer 10

A/A – ferments sucrose in TSI

K/A – Does not ferment glucose in KIA

Question 11

What is the purpose of sodium thiosulfate

Answer 11

Source of sulfur atoms for hydrogen sulfide production

Question 12

What are the colors of E. coli colonies on Eosin methylene blue agar?

Answer 12

Green-black metallic sheen

Question 13

What are the colors of weak lactose fermenters on Eosin methylene blue agar?

Answer 13

Purple

Question 14

What are the colors of non-lactose fermenters on Eosin methylene blue agar?

Answer 14

Transparent

Question 15

What decarboxylase rxn is used to differentiate b/w Shigella A, B, C, D?

Answer 15

Ornithine – Shigella sonnei (d) is the only one positive

Question 16

What orgs are urease positive?

Answer 16

PPM-K – proteus, providencia ret, morganella, klebsiella

**Only PRET = urease positive

Question 17

What orgs are citrate positive?

Answer 17

Entero-Citro-Se-Pr-K

Enterobacter, Citrobacter, Serratia, Proteus, Kleb

Question 18

What are the lysine, arginine, and ornithine rxns for Salmonella

Answer 18

Positive for all – Tube will be purple + black

Question 19

What are the lysine, arginine, and ornithine rxns for Enterobacter aerogenes?

Answer 19

+, -, +

Question 20

What are the lysine, arginine, and ornithine rxns for Enterobacter cloacae?

Answer 20

-, +, +

Question 21

What color indicates a positive rxn for lysine, arginine, and ornithine rxns

Answer 21

Purple

Question 22

What orgs are H2S positive

Answer 22

Salmonella, Citrobacter, Proteus, Edwardsiella

Question 23

What orgs are non-motile

Answer 23

Shigella and Klebsiella

Question 24

What orgs are indole positive

Answer 24

Ecoli, KOXY, Edwardsiella, Morganella, Proteus vulgaris, Providencia, Pleisimonas

Question 25

What Citrobacter produces H2S?

Answer 25

Citrobacter freundii

Question 26

What Citrobacter produces indole?

Answer 26

C. koseri

Question 27

What is the main way to distinguish between Salmonella and Citrobacter freundii?

Answer 27

LYSINE
lysine (+) in Salmonella
lysine (-) in CFREU

Question 28

Serratia can be distinguished from Enterobacter because Serratia is DNAase ______ (pos/neg)

Answer 28

Positive

Question 29

In the test for urease production, ammonia reacts

to form which product?

Answer 29

Ammonium carbonate