A Growth-Inhibitory Effect on Shigella dysenteriae which Occurs with some Batches of Nutrient Agar and is Associated with the Production of Peroxide

Abstract
SUMMARY: Certain batches of nutrient agar were inhibitory to small inocula of Shigella dysenteriae. The inhibitory effect was abolished by catalase and by manganese dioxide. It occurred only with surface cultures incubated aerobically; poured plates or plates incubated anaerobically showed no inhibition. The inhibitor was a peroxide formed during the heating of nutrient broth and agar; it was present in minimal inhibitory concentrations since dilution with one to four volumes of saline agar removed the inhibition. It is suggested that some nutrient agars contain material which, on exposure to air, forms inhibitory concentrations of peroxide in the surface layer.

This publication has 1 reference indexed in Scilit: