TABLE 1.

Hydrogen peroxide penetration and killing of wild-type and catalase mutant P. aeruginosa biofilms^a

Strain	Biofilm thickness (μm)	CS/Cob at:		Biofilm LRc at:		Planktonic LR at 60 min
		20 min	60 min	20 min	60 min
PAO1	130 ± 20	0.04 ± 0.03	0.24 ± 0.23	0.31 ± 0.10	0.26 ± 0.15	4.6 ± 1.0
katA mutant	90 ± 10	0.61 ± 0.24	0.83 ± 0.17	1.1 ± 0.2	2.6 ± 0.3	6.4 ± 0.1
katB mutant	170 ± 20	0.15 ± 0.12	0.50 ± 0.24	0.01 ± 0.08	0.13 ± 0.10	5.5 ± 0.5
katA katB mutant	130 ± 20	0.9 ± 0.05	0.92 ± 0.08	0.8 ± 0.4	1.9 ± 0.2	NDd

^aAll values are means and standard errors of the means for three or four replicates. 

^bC_S/C_o, concentration of hydrogen peroxide measured within approximately 10 μm of the substratum divided by concentration of hydrogen peroxide in the bulk fluid. 

^cLR, log reduction in viable microorganisms. 

^dND, not determined.