The effect of pH on the minimum bactericidal concentration of nitrite. The average minimum bactericidal concentrations (MBC) of nitrite for the seven MRSA strains (2-8) isolated from wounds was compared with the MBC for the MSSA control strain under different pH conditions after either 2 or 24 hours of exposure. HCl was used to acidify the nutrient broth. The error bars represent the standard deviation of the mean MBCs for all seven MRSA strains. At pH 4.5, the maximum concentration of sodium nitrite used in our assay had no effect on the viability of the MSSA strain after 2 hours hence no MBC value is shown.