THE VITAMIN REQUIREMENTS OF CERTAIN ALPHA-HEMOLYTIC STREPTOCOCCI ISOLATED FROM THE HUMAN MOUTH

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Abstract
The vit. requirements of 68 strains of streptococci, isolated from the human mouth, were studied according to the method of Smiley, et al. Fourteen strains, identified as S. fecalis, require riboflavin, Ca pantothenate, biotin, niacin, and pyridoxine. Thirteen strains, resembling S. salivarius, require riboflavin, Ca pantothenate, biotin, niacin, and thiamine. Of the remaining 41 strains, all of which were tentatively identified as S. mitis, 15 demonstrated an absolute requirement only for biotin. Serial subculture required addition of riboflavin, Ca pantothenate, and niacin as well as biotin. Four strains exhibited a variable requirement for either folic acid or riboflavin in the presence of Ca pantothenate, biotin, niacin, and pyridoxine, while 5 strains could be made to exhibit no definite vit. requirement. In addition, these last appeared diphtheroidal in the absence of yeast extract. The balance of the collection requires an as yet unidentified factor in yeast extract.

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