Flowchart of Identity Testing - Group post 1

7 Biochemical Identity Tests

(1) Kligler Iron Agar Test
It is used primarily to determine the carbohydrate fermentation and hydrogen sulphate production.
Slant
Butt
Acid Yellow
Acid Yellow
Alkaline Red
Alkaline Red

Red slant/ yellow Butt = Glucose fermented
Yellow slant/ yellow butt = Glucose fermented + lactose fermented
Red slant/ red butt = neither of them fermented

(2) Simon Citrate Agar Test
It is used to determine if an organism is capable of using citrate as sole source carbon for metabolism and growth
Positive
Growth with/ without an intense blue colour on the slant
Negative
No growth, no colour change

(3) Motility Test
It is used to determine if a microorganism is motile.

(4) Urea Hydrolysis Test
It to detect urease activity of both rapidly urea positive organism as well as a number of enterobacteriacae
Positive
Pink colour on the slant
Negative
No change in colour (pale yellow)

(5) Phenylalanine Deaminase Test
It is to determine the ability of organism to deaminate phenylalanine to phenylpyruvic acid
Positive
Light to dark green on the slant
Negative
No change in colour (yellow)

(6) Malonate Test
It is to determine the ability of organism to use malonate as a source sole of carbon
Positive
Light Blue to deep blue throughout the medium
Negative
No change in colour

(7) Indole Test
It is to determine the ability of organism to hydrolyze and deaminate tryptophan with the production of indole, pyruvic acid and ammonia
Positive
Red halo ring seen
Negative
No change in colour (yellow)