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Table 3 Overview of combined mechanism of ciprofloxacin resistance within qnrS, acrAB-tolC positive Enterobacteriaceae

From: Contribution of target alteration, protection and efflux pump in achieving high ciprofloxacin resistance in Enterobacteriaceae

Organism ID MIC (µg/mL) Plasmid mediated qnrS gene Efflux pump mediated resistance Amino acid substitution in QRDR of DNA gyrase subunit A
No. of plasmids extracted (approximate size in kb) Size (in kb) of plasmid harboring qnrS gene Effect of NMP on the action of CIP Amino acid substitution in regulatory gene products
AcrR MarR
Escherichia spp. E23 512 No plasmid Additive H115Y G103S, Y137H, A53E S83L, D87N
E34 512 No plasmid Additive H115Y G103S, Y137H, A53E S83L, D87N
26N 256 5 (<2.1, 2.7, 3.0, 4.6, >54.2) 1 (<2.0) Additive H115Y G103S, Y137H, A53E S83L, D87N
28N 256 6 (<2.1, <2.1, 2.5, 2.8, 3.1, 3.9) None Additive T213I, N214T G103S, Y137H, K62R S83L, D87N
CR1 512 1 (>54.2) 1 (>54.2) Synergistic No substitution G103S, Y137H S83L
CR2 512 7 (~2.3, 2.5, 3.7, 3.9, 5.2, 54.2, >54.2) 1 (>54.2) Synergistic No substitution G103S, Y137H S83L, D87N
CR4 512 5 (<2.1, 2.9, 3.0, 3.5, >54.2) None Synergistic ND ND S83L, D87N
MCX14 256 2 (3.1, >54.2) 1 (>54.2) Additive ND ND S83L, D87N
NCX9 256 2 (~54.2, >54.2) None Additive No substitution G103S, Y137H No substitution
G4 256 4 (~2.4, 2.7, 3.9, >54.2) None Additive T213I, N214T G103S, Y137H, K62R S83L, D87N
Enterobacter spp. MCX5 512 5 (2.0, 2.2, 2.8, 3.9, >54.2) None Synergistic ND ND S83L, D87N
MCX6 256 3 (2.0, 2.2, >54.2) 1 (2.2) Additive ND ND S83Y
NCX14 256 1 (3.9, 7.0) 2 (3.9, 7.0) Additive ND ND S83L, D87N
Klebsiella spp. E33 256 No plasmid Additive ND ND Not done
NCX6 512 9 (<2.0, 2.0, 2.5, 3.0, 3.5, 4.8, 5.0, 54.2, >54.2) None Synergistic ND ND Not done
MCX10 512 8 (<2.0, 2.5, 2.7, 3.9, 4.0, 5.0, 54.2, >54.2) 3 (2.5, 2.7, >54.2) Synergistic ND ND S83L
Salmonella spp. 74 256 No plasmid Additive ND ND S83L, D87N
77 512 No plasmid Additive ND ND S83L, D87N
  1. ND not determined