ACID-PRODUCTION AS A BASIS FOR CLASSIFYING LACTOBACILLI FROM CARIOUS TEETH

¹ laboratories of the Department of Bacteriology, University of Sydney, Australia

1. Over 100 strains of oral lactobacilli have been isolated from carious teeth and examined by several methods, chiefly to determine their acidogenic powers.

2. On the basis of acid production from glucose, these strains have been grouped as follows: (a) S.A., those which produce a large quantity of acid. (b) W.A., those which produce a much smaller quantity.

3. This grouping is well supported by other biochemical properties such as (a) fermentation reactions, particularly with raffinose, salicin and mannitol and (b) ability to grow on a medium containing sodium taurocholate.

4. From a comparison of our results with those of Enright, Friesell and Trescher it would appear that our S.A. type corresponds to their Group I, and our W.A. type to their Group II, which groups they identify with Rettger and Horton's Y and X types respectively.