Table 1.

In vitro susceptibility to finafloxacin and other fluoroquinolones under standard testing conditions and at slightly acidic pH

OrganismSusceptibility to ciprofloxacinaNo. of isolates testedAntibioticMIC (mg/liter) at:b
pH 7.2–7.4pH 5.8–6.2
RangeMIC50MIC90RangeMIC50MIC90
Community-associated MRSASusceptible33Finafloxacin0.125–0.250.1250.250.06–0.1250.060.125
Ciprofloxacin0.25–10.511–414
Moxifloxacin0.03–0.1250.060.1250.25–0.50.250.5
Staphylococcus aureusResistant30Finafloxacin0.25–322160.25–3214
Ciprofloxacin4–>6432>6416–>6432>64
Levofloxacin4–>642324–>6416>64
Moxifloxacin2–322320.5–64832
Coagulase-negative staphylococcusSusceptible26Finafloxacin0.015–0.50.250.50.008–10.060.125
Ciprofloxacin0.06–10.250.50.125–40.51
Resistant16Finafloxacin0.06–>168160.125–16116
Ciprofloxacin2–>16>16>168–>16>16>16
Streptococcus pneumoniaeMixed21Finafloxacin0.5–412NDNDND
Ciprofloxacin1–424NDNDND
Levofloxacin0.5–212NDNDND
Moxifloxacin0.125–0.50.51NDNDND
Streptococcus pyogenesSusceptible22Finafloxacin0.25–10.50.50.125–0.50.250.25
Ciprofloxacin0.125–10.510.25–212
Moxifloxacin0.125–0.50.250.250.25–10.50.5
Streptococcus agalactiaeMixed11Finafloxacin0.5–4120.125–40.250.5
Ciprofloxacin0.5–4120.5–412
Enterococcus faecalisMixed10Finafloxacin0.5–321320.25–160.516
Ciprofloxacin0.5–1281642–>2564>256
Enterococcus faeciumMixed9Finafloxacin1–128NCNC0.5–32NCNC
Ciprofloxacin1–256NCNC2–>256NCNC
Escherichia coliResistant75Finafloxacin16–>2561282562–64832
Ciprofloxacin8–>256128>256>256>256>256
Levofloxacin8–128326432–>256256>256
Susceptible12Finafloxacin0.03–10.1250.25≤0.008–0.1250.0160.03
Ciprofloxacin≤0.008–0.1250.0160.030.06–20.1250.25
Klebsiella spp.Susceptible16Finafloxacin0.06–40.2520.008–10.060.5
Ciprofloxacin0.016–10.030.50.125–80.58
Resistant7Finafloxacin2–>32NCNC0.5–>32NCNC
Ciprofloxacin2–>16NCNC8–>16NCNC
Salmonella spp.Mixed8Finafloxacin0.5–16NCNC0.06–4NCNC
Ciprofloxacin0.125–32NCNC1–>32NCNC
Levofloxacin0.25–16NCNC0.5–>32NCNC
Moxifloxacin0.25–16NCNC1–>32NCNC
Proteus mirabilisMixed10Finafloxacin0.5–>321160.06–80.254
Ciprofloxacin≤0.008–10.01610.06–>160.1258
Providencia spp.Mixed11Finafloxacin0.06–16816≤0.03–818
Ciprofloxacin≤0.03–16140.125–>1616>16
Levofloxacin≤0.03–16120.06–>168>16
Moxifloxacin≤0.03–160.520.125–>168>16
Enterobacter spp.Susceptible10Finafloxacin0.06–0.50.1250.125≤0.03–0.125≤0.03≤0.03
Ciprofloxacin≤0.03≤0.03≤0.030.06–0.50.1250.25
Levofloxacin≤0.03–0.06≤0.030.060.125–0.50.250.5
Moxifloxacin≤0.03–0.25≤0.030.060.125–20.250.5
Morganella morganiiMixed11Finafloxacin0.125–161160.03–160.254
Ciprofloxacin≤0.008–>160.00840.016–>160.06>16
Serratia marcescensSusceptible12Finafloxacin0.125–8180.06–40.252
Ciprofloxacin≤0.03–1≤0.0310.125–>16116
Levofloxacin≤0.03–40.12510.25–>16116
Moxifloxacin0.06–40.12521–>164>16
Stenotrophomonas maltophiliaMixed19Finafloxacin0.5–32240.125–160.51
Ciprofloxacin0.5–64482–256864
Pseudomonas aeruginosaSusceptible22Finafloxacin1–324160.25–80.52
Ciprofloxacin0.03–10.250.50.125–20.51
Resistant9Finafloxacin>32NCNC16–>32NCNC
Ciprofloxacin8–32NCNC8–>32NCNC
Haemophilus influenzaeSusceptible35Finafloxacin≤0.004–0.060.0080.03NDNDND
Ciprofloxacin0.008–0.030.0080.016NDNDND
Levofloxacin0.008–0.030.0160.03NDNDND
Moxifloxacin≤0.004–0.1250.0160.06NDNDND
Neisseria gonorrhoeaeMixed10Finafloxacin≤0.03–0.250.060.125≤0.03–0.1250.060.06
Ciprofloxacin≤0.03–0.1250.060.06NDNDND
Levofloxacin0.06–0.250.060.250.06–0.1250.060.125
Moxifloxacin≤0.03–0.1250.060.06NDNDND
  • a According to the CLSI susceptibility breakpoint for ciprofloxacin (3). Mixed, susceptible and resistant.

  • b ND; not determined (usually strains grew poorly at low pH); NC, MIC50 and MIC90 were not calculated for groups of less than 10 strains.