%0 Journal Article %A WATSON, J. A. %A SCHUBERT, J. %T Action of Hydrogen Peroxide on Growth Inhibition of Salmonella typhimurium %D 1969 %J Microbiology, %V 57 %N 1 %P 25-34 %@ 1465-2080 %R https://doi.org/10.1099/00221287-57-1-25 %I Microbiology Society, %X SUMMARY The effect of hydrogen peroxide on the growth of Salmonella typhimurium lt2 in a mineral glucose medium was investigated. The H2O2 produced a lag period, the duration of which increased as the concentration of H2O2 in the medium was increased from 1 to 60 μg./ml. Growth subsequent to the lag period proceeded at the normal growth rate at concentrations of H2O2 as high as 30 μg./ml. Storage of H2O2 in the sterile growth medium resulted in a disappearance of H2O2 with a half-life of about 48 hr. The disappearance of H2O2 because of reaction with glucose resulted in proportionate decreases in the growth inhibitory action of the medium. Salmonella typhimurium destroyed H2O2 rapidly (half-time = 60 min.)–an effect attributed largely to bacterial catalase. The catalatic activity of the bacteria was decreased or eliminated by boiling or by treatment with cyanide. The growth of the bacteria in H2O2 resulted in the development of H2O2 resistance. By subculturing the wild type lt 2 in medium containing successively higher H2O2 concentration, a resistant strain designated lt2 p was isolated which grew in the presence of H2O2 concentrations that were completely inhibitory to the wild type. The experimental results support the generally accepted conclusion that bacterial catalase acts in protecting the organism from H2O2. It is pointed out that in biological media H2O2 readily forms adducts with many compounds, including carbonyls, amino acids and thymine. Consequently, the inhibitory effects of H2O2, especially in studies involving auxotrophs, may be partly or wholly due to the peroxide adduct rather than ‘free’ H2O2. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-57-1-25