Studies on the Interference of Certain Substances of Biological Importance with the Action of Sulfanilamide

Abstract

The effects of certain substances upon the growth of E. coli and upon the action of sulfanilamide were studied. The synthetic medium used by Bliss and Long (pH 7.2) was employed. Twenty cc. amts. with or without 10 mg. % of sulfanilamide and with or without the substance being studied were used for each test. The inoculum consisted of 0.2 cc. of a 1:100,000 saline dilution of an 18 hr. culture of E. coli, subcultured into 5 cc of the synthetic medium. The number of organisms present at the beginning and after from 2-24 hrs.'' incubation at 37 [degree]C was detd. by plating in extract agar containing 5 mg. % of p-aminobenzoic acid. Dextrose increased the growth rate of the organisms, regardless of whether the conc. of dextrose was 0.08% or up to 6.2%. In the presence of 10 mg. % of sulfanilamide definite interference with the action of this drug was observed in 24 hrs. in the presence of from 0.6% through 2.6% dextrose. Glutamic acid and glutamine (from 147-14.7 mg. %) also interfered with the action of sulfanilamide. Under the conditions of the expts. none of the vits. tested (biotin; nicotinic acid; nicotinamide; pantothenate Na; riboflavine; thiamine hydrochloride) played a significant role in either stimulating or in interfering with the action of sulfanilamide.