Table 1.

Hydrogen peroxide penetration and killing of wild-type and catalase mutant P. aeruginosa biofilmsa

StrainBiofilm thickness (μm)CS/Cobat:Biofilm LRcat:Planktonic LR at 60 min
20 min60 min20 min60 min
PAO1130 ± 200.04 ± 0.030.24 ± 0.230.31 ± 0.100.26 ± 0.154.6 ± 1.0
katAmutant90 ± 100.61 ± 0.240.83 ± 0.171.1 ± 0.22.6 ± 0.36.4 ± 0.1
katBmutant170 ± 200.15 ± 0.120.50 ± 0.240.01 ± 0.080.13 ± 0.105.5 ± 0.5
katA katBmutant130 ± 200.9 ± 0.050.92 ± 0.080.8 ± 0.41.9 ± 0.2NDd
  • a All values are means and standard errors of the means for three or four replicates.

  • b CS/C o, concentration of hydrogen peroxide measured within approximately 10 μm of the substratum divided by concentration of hydrogen peroxide in the bulk fluid.

  • c LR, log reduction in viable microorganisms.

  • d ND, not determined.