Cultural Characteristics of Streptococcus
1. They are aerobic and facultative anaerobes.
2. They grow best at 37 degree Celsius.
3. Group D grow well at between 10 degree Celsius and 45 degree Celsius.
4. Growth is poor on solid media or broth.
5. Grow well in media containing blood and sugar ( fermentable carbohydrates) and 10% CO2 in environment promotes growth and hemolysis.
6. Selective media containing aminoglycosides or 1:500,000 crystal violet selectively permit the growth of Streptococci in a mixed culture and inhibit other bacteria.
7. Colony on blood agar is non-pigmented.
8. Complete hemolysis ( B-hemolysis) on blood containing agar.
9. Alpha hemolysis shows greenish coloration due to hydrogen peroxide released from the colonies and inducing oxidation of hemoglobin to methemoglobin.