File:Group A streptococcus09.jpeg

This photograph depicted a colony of a Streptococcus salivarius growing in the Petri dish filled with trypticase soy agar with 5% sheep's blood, (BAP). A loop of diluted culture of S. salivarius was put into the melted agar (50oC) just before the blood was added. The melted agar with blood was allowed to solidify, and then incubated at 35oC for 24 hours in a normal atmosphere. The culture grew subsurface bacterial colonies, one of which is seen here. There were no color changes in the region surrounding the colony, indicating that the red blood cells in the blood agar medium have not been altered in any way, which meant that these bacteria were indeed non-hemolytic in nature.