Effect of glucose perturbation on E. coli K-12 biofilm culture antibiotic tolerance for wild-type and glucose negative mutants. Cultures were grown as biofilms for 6 hours before being transferred to antibiotic treatment plates for 24 hours. Conditions included only LB medium and LB medium supplemented with 10 g/L of glucose. Reported cfu/biofilm data was determined after treatment. Δglc- glucose negative E. coli K-12 strain (ΔptsG, ΔptsM, Δglk, Δgcd). Black bars = control, dark gray bars = kanamycin (100 ug/ml), light gray bars = ampicillin (100 ug/ml) challenge. Number at the base of each bar denotes the number of independent replicates. cfu = colony forming unit.