Column Key Abbreviations: CIP = ciprofloxacin CST = colistin TOB = tobramycin Anc = ancestor strain, i.e., bacterial isolate used to begin transfer experiment Experimental Treatment = Treatment during transfer experiment (except for Anc) Experimental Culture = Culture composition during transfer experiment (except for Anc) Replicate = Replicate population during transfer experiment (0 = Anc) Pseudomonas_alive = Pseudomonas present in culture at the end of transfer experiment Stenotrophomonas_alive = Stenotrophomonas present in culture at the end of transfer experiment 1 = alive; 0 = extinct Optical Density = Optical density at 600nm Antibiotic = Antibiotic used during growth assay Concentration = Antibiotic concentration used during growth assay (µg/ml) MIC = MIC value of antibiotic (µg/ml)