Abstract
Since oysters have been shown to be a good source of vitamins A, B, C, and D as well as to contain in considerable amounts the inorganic elements iron, copper, manganese, zinc, lead, arsenic and iodine, 1 the possibility of the use of oysters in culture mediums was suggested. It was found that many organisms, including the group of acid-fast bacteria, grow quite luxuriantly on certain of the mediums prepared. Two solid egg-oyster mediums, one made with the yolks and the other with the whites, and a hormone oyster infusion broth have proven to be the most satisfactory of all preparations.
Six strains of Mycobacterium tuberculosis (H 37, Ru a virulent human strain obtained from Dr. Novy, a virulent bovine strain, a virulent avian strain and an avirulent strain) and 9 strains of chro-mogenic acid-fast bacteria isolated from lepers by several investigators all give typical growth on both the egg white and egg yolk oyster mediums. The strain of M. leprae isolated by McKinley and Soule 2 , 3 , 4 has been successfully cultivated on the egg white oyster when incubated in an atmosphere of 10% carbon dioxide and 40% oxygen for 30 days, but does not appear to multiply on the egg yolk oyster medium when incubated under similar conditions. The value of these mediums for the isolation of acid-fast organisms is being studied further.
The egg oyster mediums are prepared by mixing (a) 2 parts of egg white with 1 1/2 parts of minced oyster; or (b) 1 1/2 parts of egg yolk, 1/2 part of whole egg and 2 parts of minced oyster. The pH of each mixture is adjusted to about 8.2. The tubes are placed in an inspissator at a temperature of 70 to 80 °C. immediately upon filling so that the tissue does not settle to the bottom of the tubes before coagulation.
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