For cultivation of fastidious and nonfastidious microorganism especially H. influenzae, N. meningitidis, S. pneumoniae
Medium contains pancreatic digest of Casein and papaic digest of soybean supports the growth of many fastidious organisms without the addition of serum etc. Glucose serves as a carbohydrate source. Dibasic hydrogen phosphate acts as a buffering agent respectively. Sodium chloride maintains osmotic balance of the medium. The growth of microorganisms in a blood culture medium may be delayed or prevented if an anticoagulant is not used in the culture medium since the organisms may become trapped in the fibrin clot. However, some anticoagulants may be toxic for certain pathogens. In addition, blood has natural bactericidal or bacteriostatic action due to the presence of natural bacterial inhibitors such as antibodies, complement, ß-lysin and phagocytes as well as antibiotics used in the therapy may greatly delay or reduce, if not completely eliminate the chances of obtaining a positive culture. These obstacles may be overcome by the use of substances such as liquid / sodium polyanetholsulfonate (SPS), a nontoxic anticoagulant which enables bacterial growth by obstructing the natural bacterial inhibitors of blood. Since SPS inhibits the activity of streptomycin, polymyxin B, kanamycin and gentamicin, therapy with these antibiotics should not interfere with microbial growth in blood cultures containing this anticoagulant.