Terminal Alkalinity in Saliva-Phenol Red Glucose Broth Cultures

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Abstract
Frequent reversion (15%) to alkaline side of indicator, phenol red, in 4-30 days after initial acidity in saliva-glucose broth mixtures indicated attack on organic nitrogenous substances to release basic end products. This reaction was caused almost exclusively by members of the genus Candida, which occur in about 25% of all specimens of saliva. Of these strains, only 60% caused reversion in the saliva-broth cultures, but under controlled conditions testing each component of medium, peptone, meat extract, and glucose, under varying pH, all strains tested (30) produced terminal alkalinity in 30 days at 37[degree]C. Glucose in concn. of 1% delayed but did not prevent this reaction.