FIGURE 7.

CO₂ production (μmol/h) of biofilms inoculated from bench cultures exposed to streptomycin in 0.3 g/l TSB medium for 4-h intervals. (A) Multispecies culture grown on 0.3 g/l TSB medium and exposed to 4000 mg/l streptomycin. The effluent cell numbers decreased from 2.0 × 10⁷ CFU/ml at steady state to 9.0 × 10² CFU/ml at the end of the first 4 h exposure. In contrast, the second exposure did not result in a similar decrease of effluent cell numbers; which were 2.4 × 10⁵ CFU/ml at the end of the 4 h exposure (B) P. aeruginosa on 0.3 g/l TSB medium and exposed to either 4000, 8000, or 12,000 mg/l streptomycin (C) an Enterobacter species biofilm (D) Enterobacter asburiae biofilm, and (E) a Pseudomonas putida biofilm, and (F) a multispecies biofilm grown for 5 days prior to the streptomycin exposure.