This document discusses various biochemical tests used to identify bacteria, including: IMViC tests (Indole, Methyl Red, Voges-Proskauer, Citrate) which identify bacteria based on their reactions in different media. Other tests discussed include urease, oxidase, catalase, coagulase, hemolysis, hydrogen sulfide, and pigment formation tests. The document also notes that enzymes produced by bacteria can be constitutive or adaptive, and intracellular or extracellular.

1. Biochemical Tests
Principles
Reagents & Media
Procedures & Results

3. IMViC
x Indole - x Methyl Red -
– product of hydrolysis – pH indicator
of tryptophan – production of
– Reagent - (Ehrlichs) sufficient acidity
Para-dimethyl- from glucose
aminobenzaldehyde – Media- MR-VP
– (+) pink or red color broth
– (+) red - acid
– (-) yellow - alkaline

5. IMViC (2)
x Vogues Proskauer - x Citrate Utilization Test
– production of – citrate as a source
acetyl-methyl of Carbon
carbinol from – media :Simmon
glucose Citrate (SCA)
– media: MR-VP – (+) blue color
broth – (-) green color
– reagent: 40% KOH
– (+) production of an
eosin like color

7. Biochemical Tests (3)
x Urease Test - x Oxidase Test -
– Hydrolysis of urea – catalysis of Oxidase
by Proteus sp. through cytochrome
– media: by N. gonorrhea
Christensen’s urea – media: CAP
– (+) Pink color media – reagent: 1% para-
/hemolysis amino-dimethyl-
– (-) colorless aniline hydrochloride
– (+) black

9. Biochemical Tests (4)
x Catalase Test - x Coagulase Test -
– decomposition of – coagulation of
3% Hydrogen plasma with enzyme
peroxide coagulase by
– (+) rapid evolution pathogenic
of gas staphylococcus
– organisms: – media: Blood plasma
y(+) staphylococci – (+) clotting of plasma
y micrococci
y (-) streptococci

11. Biochemical Tests (5)
x Hemolysis test - x Hydrogen Sulfide
– destruction of RBC test -
– media : Blood agar – production of
plate Hydrogen sulfide
– (+) clearing zone – any media with
x Greig’s Test Fe
– hemolysis of – (+) black ppt.
sheep’s rbc x Pigment formation
– (+) El tor (-) vibrio – chromogens

13. Enzymes produced by bacteria:
x Constitutive - essential enzymes
x Adaptive - non-essential enzymes
x Intracellular
x Extracellular