Factors that promote the growth of Brucella in the presence of blood.

The data presented show that the growth of brucella cells in a mixture of culture medium (peptone type) and blood is not due to growth-promoting constituents in the medium but to the presence of an agent or agents that inactivate the bacterial growth-inhibiting factor usually present in normal blood. The blood then becomes an excellent culture medium.Other methods of inactivating the growth-inhibiting factor in normal cow blood to promote a rapid growth of Brucella involve the acidification of the culture medium in order to obtain a final pH of 6.0-6.2 after the addition of blood, and the presence of a cation exchange resin (H(+)) in blood alone.Rapid growth of all types and species of Brucella was obtained in cow, human, and horse blood alone by the addition of a cation exchange resin (H(+)). In the presence of salts in the blood, the resin behaved like an acid in lowering the pH to the desired level of 6.0-6.2.If conditions are created in a closed container (bottle), so that CO(2) is released from the NaHCO(3) normally present in blood, other measures, such as the artificial addition of CO(2), are rendered unnecessary in any procedure for the growth of CO(2)-dependent strains of Brucella abortus in the presence of blood.