design: Genomic DNA was extracted from E. coli cultures after 24 h incubation with or without ciprofloxacin treatment using the MagPure Bacterial DNA Kit. The sgRNA region of the CRISPRi library was amplified using primers targeting the constant flanking sequences. PCR products were gel-purified and indexed using Nextera adapters. Sequencing libraries were constructed with the NEBNext Ultra II DNA Library Prep Kit and sequenced on an Illumina MiSeq platform (paired-end 150 bp).