Schematic of the CompAReSeq barcode sequencing method. Each strain includes a unique 7 bp barcode on the pZE24 plasmid. Strains harboring tetracycline resistance genes, plus an empty plasmid control, were mixed at equal relative abundances. These were then inoculated into media containing antibiotics at different concentrations. Following growth for 20-48 h, plasmid DNA was extracted and prepared for sequencing using two PCR steps that added sample-specific barcodes and UMIs, then added sequencing adapters and amplified DNA. The output amplicons were then sequenced, and the number of UMIs identified per barcode was counted.
