Abstract
In producing mass cultures of streptococci and pneumococci, Mueller and Klise 1 found it distinctly advantageous to maintain approximate neutrality of cultures growing in 2% glucose broth; this was accomplished by frequent additions of sterile NaOH. The yield of cocci and/or of soluble specific substance was considerably enlarged. We have applied their method in a study of the production of other bacterial products— the erythrogenic toxins and the lysin of the N.Y. 5 strain of hemolytic streptococcus.
Comparisons of the activities of this strain in 1 L. quantities of tryptic digest broth, pH 7.9, 3.82 mg. N2/ml, were made under 3 conditions: I, 2% glucose and phenol red were added to basic medium and, after growth began, the color was kept faintly pink by repeated small additions of 10% NaOH—84 ml were used in 24 hours; II, basic medium containing indicator and 2% glucose; III, basic medium and indicator. Each 2 L. flask was seeded with 5 ml of a 6 hour broth culture; at successive 4 hour intervals, samples were withdrawn for tests. Observations are recorded in the figure and table.
Hemolytic activity of centrifugates was at once measured at 37°C. in the presence of 0.5 ml of 5% rabbit cells; total volume, 1 ml; incubation, 1 hr.
The bacterial bulks were measured by uniform centrifugation and are charted as volume percent. The cocci in lot 1 were notably small and usually gram-negative; used as a bacterial vaccine this suspension has evoked larger local reactions than ordinary suspensions of apparently the same density.
Toxins were titrated on subjects who responded with bright, 20 mm. reactions. Estimates of the skin-test dose (STD) are considered accurate only within 50%. The potency of toxin “B”, 2 also produced by this strain, was measured and found to parallel that of the Dick toxin (“A”) except that in lot II after 8 hours it rapidly declined and at 20 hours there were less than 100 STD/ml of “B” toxin remaining.
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