['Hyperglycemia is a risk factor for nosocomial infections with known host effects. Increased glucose levels also increase pathogenicity of infecting microbes through greater biofilm formation. The dose response of biofilm formation to glucose concentration is not known.', 'We asked: What is the relationship between the amount of biofilm formed by Staphylococcus epidermidis and Staphylococcus aureus and change in glucose concentration in the clinically important range of 20 to 300\xa0mg/dL?', "This experiment studied biofilm formation by S epidermidis and S aureus in Lennox broth medium supplemented with increasing glucose concentrations from 0 to 320\xa0mg/dL in 20 mg/dL intervals. Biofilm was grown for 24 hours for S epidermidis and 48 hours for S aureus. Biofilms were heat fixed, stained with 0.1% crystal violet, and washed with deionized water. The dye was then extracted with 30% acetic acid. Visual light absorption of the extracted crystal violet dye at 600\xa0nm was used to quantify the biofilm biomass. The effect of glucose concentration on the amount of biofilm mass produced was analyzed using ANOVA and Tukey's test.", 'Biofilm mass was increased at higher glucose concentration for both species with a threshold response at 0 to 20 and 160 to 200\xa0mg/dL for S epidermidis and 200 to 240\xa0mg/dL for S aureus.'] Does biofilm growth have a threshold response to glucose in vitro?