TSI

Question 1

Triple sugar iron (Gram -)

Answer 1

Can it utilize sugars: glucose (0.1%), lactose (1.0%), sucrose (1.0%)

Question 2

Ingredients

Answer 2

Glucose
Lactose
Sucrose
Phenol red
Peptone
Thiosulfate
Ferric ammonium citrate

Question 3

Phenol red (lactose metabolized?)

Answer 3

pH < 6.8

Question 4

Peptone (partially hydrolyzed)

Answer 4

If peptone used, ammonia produced = pH back to alkaline = back to red

Question 5

CO2 released (decarboxylation)

Answer 5

Gas pocket present, krebs cycle

Question 6

Thiosulfate

Answer 6

Sugar metabolized = acidic environment = sulfur released

Question 7

If sulfur can act as terminal electron acceptor

Answer 7

Product is H2S (hydrogen sulfide)

Question 8

Ferric ammonium citrate

Answer 8

Binds with H2S = black color