TABLE 3.

Data from quantitative image analysis of P. aeruginosa PAO1 biofilms^a

Duration of imipenem exposure	Biomass (μm3/μm2)	Avg thickness (μm)	Surface-to-biovolume ratio (μm2/μm3)
Control	10.8 ± 1.2	15.2 ± 2.4	1.7 ± 0.1
18 h	17.2 ± 1.7	22.0 ± 2.5	1.5 ± 0.3
37 h	18.1 ± 1.5	21.0 ± 1.8	1.2 ± 0.1

^aQuantitative image analyses were performed to compare the architectures of imipenem (0.5 μg/ml)-exposed biofilms and unexposed biofilms (control) on day 5. The values are the averages of 10-image stacks from each flow cell channel acquired in one experiment. The biomass is calculated as the biomass volume (in cubic micrometers) per substratum surface area (in square micrometers). The thickness is the average depth of the biofilm. The surface-to-biovolume ratio describes the surface area of the biofilm (in square micrometers) per biomass volume of the biofilm community (in cubic micrometers). The data are presented as means ± 95% confidence intervals. The data were quantified with the computer program COMSTAT.