1. Classification of Bacteria

2. Macroscopic Appearance
Color - pigment produced by bacteria

3. Macroscopic Appearance
Texture - may be gloss, stringy, smooth,
dull, dry & powdery, etc.
Other: shape, size, elevation, odor, etc.

4. Shape - Primary Classification
Cocci (coccus) = spherical

5. Shape - Primary Classification
Bacilli (bacillus) = rod shaped

6. Shape - Primary Classification
Sprilla (spirillum) = spiral shaped

7. Arrangement Diplo- = pairs of bacteria Strepto- = chains of bacteria
Staphylo- = clusters of bacteria
Tetra = groups of four bacteria
Sarcinae = groups of eight bacteria

8. Arrangement

9. Arrangement

10. Response to Gram Stain
Determined by the biochemistry of the bacterial cell wall
Gram+ bacteria = purple
Gram- bacteria = reddish-pink
*medically important test to identify
bacteria

11. Response to Gram Stain

12. Other Methods of Classification
Nutrition
Oxygen requirements
Other unique features: pili, capsules,
endospores, or flagella

13. End