The blood must not be allowed to clot in the culture media because any bacteria will become trapped in the Culture medium.
Incubate the inoculated media:
35-370C for up to 2 weeks, examining and sub-culturing
Look for visible signs of bacterial growth such as turbidity above the red cell layer, colonies growing on top of the red cells (“cotton balls”), haemolysis, gas bubbles and clots.
A sterile culture usually remains clear
If there are signs of bacterial growth, subculture the broth and examine a gram stained smear for bacteria
Tryptone soya diphasic medium
up to 4 weeks. Look for colonies on the agar slope (preferably using a hand lense), and signs of bacterial growth in the broth. Colonies of staphycococ, s .typhi, brucellosis and most coliforms can usually be seen easily. Where as colonies of pneumococci, S. pyogens, and Y.pestis are not easily seen. If growth is present subculture to blood agar plate, Chocolate agar plate, MacConkey