1. “What should ______ look like?”
Bacterial Cultures
“What should ______ look like?”

2. Bacterial Shapes Coccus (cocci) Spherical Bacillus (bacilli) Rod
Spirillum (spirilla)
Spiral
Bacterial Shapes

3. Bacterial Arrangement
Staphylo-
clusters
Strepto-
chains
Bacterial Arrangement

4. Staphylococcus sp. Good Example Bad Example Bundle of grapes
Consistent color
Probably overheated
Areas appear strepto-
Staphylococcus sp.

5. Streptococcus sp. Good Example Bad Example
Consistent morphology and color
Inconsistent
Streptococcus sp.

6. Bacillus (Bacilli)
Bacillus sp.
Rod shaped bacteria
Many different species
Can be gram positive or negative etc.
Gram positive
Form endospores

7. Bacillus subtilis Good Example Bad Example Good purple color
Old or too much “de- stain”
Bacillus subtilis

8. Endospores of Clostridium botulinum
Provide long-term survival
Dormant stage
Waiting for right conditions

9. Spirilla sp. Good Example Bad Example
Note: not a pure culture but good spirilla
Inconsistent coloration
Spirilla sp.