Identification of Determinants that Allow Maintenance of High-Level Fluoroquinolone Resistance in Acinetobacter baumannii

High-level fluoroquinolone resistant Acinetobacter baumannii strains harboring mutations in the GyrA and TopoIV fluoroquinolone targets as well as mutations that increase expression of drug resistance-nodulation-division (RND) efflux pumps (gyrAparCadeS (GPS), gyrAparCadeN (GPN), and gyrAparCadeL (GPL)) were grown to mid-log (Mid) and early post-exponential (EPE) phase in the absence and presence of sub-MIC levels of Ciprofloxacin causing 20-30% growth inhibition in parallel with the gyrAparC (GP) and WT ATCC 17978UN parent strains. Their RNA was isolated for comparative RNAseq to determine transcriptional changes that support fitness of the RND pump overexpressors.