Blood culture protocol. Photograph of blood culture media showing liquid Columbia broth to the left and the dual medium to the right (a). Venting procedure in a biological safety cabinet. Note the subculture inoculation on to 5% sheep blood agar (b). Dual medium blood culture bottle (from left to right) before inoculation, day 7 and day 14. Note the absence of turbidity (c). Inoculated blood agar showing absence of growth from subcultures (d).