Delafloxacin against Helicobacter pylori, a potential option for improving eradication success?

Increase in Helicobacter pylori resistance to fluoroquinolones has been reported in many countries. The aim of the study was to compare, for the first time to our knowledge, levofloxacin and delafloxacin activities against H. pylori, including numerous levofloxacin- and multidrug resistant strains. Minimal inhibitory concentrations (MICs) of six antibiotics against 71 consecutive clinical strains were determined. Delafloxacin MIC50 and MIC90 were 0.016 and 0.125 μg/mL versus 0.125 and ≥32 μg/mL, respectively, for levofloxacin. Against the 19 levofloxacin resistant strains, delafloxacin MICs50 and MICs90 were 0.094 and 0.38 μg/mL, respectively. Delafloxacin MICs against the 21 strains with double or multidrug resistance were ≤0.75 μg/mL. The low MICs, the activity against levofloxacin resistant and multidrug resistant H. pylori strains and the increased activity of the agent in acidic conditions make delafloxacin worthy of further investigation, aiming at optimizing fluoroquinolone-based eradication regimens.