Growth of bacteria in blood: use of cation exchange resins for enhancing or suppressing growth.

It has been demonstrated experimentally that small numbers of a variety of different bacteria fail to survive or multiply in normal cow or human blood or in a mixture of blood and a suitable culture medium, owing to the binding of the magnesium ion and a protein component of the antimicrobial system. However, a satisfactory and simple method has now been evolved for the rapid multiplication of Gram-negative and Gram-positive bacteria in blood without the addition of a liquid culture medium. This method involves the addition to blood of optimum amounts of hydrogen and magnesium ion exchange resins and sodium citrate.