Characterization and identification of bacteria

1
Characterization and identification of bacteria

• Based on phenotype

2
Systematics (taxonomy) of bacteria

• Study of diversity of microorganisms and their
  relationships
• Includes
• clasification (ordering of B. into groups)
• nomenclature
• identification

3
Most important classes of characters

• Morfological (cels including staining)
• Cultural
• Physiological
• Nutritional
• Biochemical
• Ecological
• Genetic
• Antigenic
• Phage susceptibility

4
In classification of bacteria

• As many charactes as posible should be studied
• describtion of new species

5
In identification of bacteria

• Number of tests applied should be kept to a
  minimum
• concetration for simple methods and for
  characters with very good distinguishing value
• tests must be standardized

6
Characteristics of primary importance I.

• 1. Pure culture (make sure to have)
• 2. Examine Gram-stained cells
• 3. Look for motility or flagela
• 4. Examine colonies

7
Characteristics of primary importance II.

• 5.Test for oxygen requirements
• 6.Test for dissimilation of glucose
  (oxidative/fermentative)
• 7.Select tests useful for distinguishing between
  the genera
• 8.Select the test apllicable for species
  identification

8
Mistakes

• Determination of shape
• Gram reaction
• Motlity

9
Biochemical characters

• Oxidase test
• Catalase test
• Carbohydrate breakdown
• O-F of glucose
• Acid formation from sugars
• Gas formation from glucose
• ONPG test (beta-galactosidase activity)

10
Biochemical characters

• Reduction of nitrate to nitrite
• Indole test
• VP test (acetoin production)
• Arginin dihydrolase test