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.

Clonal dissemination of multilocus sequence type ST15 KPC-2-producing Klebsiella pneumoniae in Bulgaria.

A total of 36 consecutive clinical and two fecal-screening carbapenem-resistant Klebsiella pneumoniae isolates from two Bulgarian university hospitals (Varna and Pleven) were investigated. Susceptibility testing, conjugation experiments, and plasmid replicon typing were carried out. Beta-lactamases were characterized by isoelectric focusing, PCR, and sequencing. Clonal relatedness was investigated by RAPD and multilocus sequence typing (MLST). Most of the isolates demonstrated multidrug resistance profile. Amikacin and tigecycline retained good activity with susceptibility rates of 95 and 87%, respectively. The resistance rate to colistin was 63%. Six RAPD- and MLST-types were identified: the dominating MLST-type was ST15 (27 isolates), followed by ST76 (six isolates), and ST1350 (two isolates). ST101, ST258, and ST151 were detected once. All except one of the K. pneumoniae produced KPC-2, mostly in combination with CTX-M-15, while for one isolate (ST101) the enzymes OXA-48 and CTX-M-14 were found. All KPC-2-producing transconjugants revealed the presence of IncFII plasmid. The OXA-48- and CTX-M-14-producing isolate showed the presence of L/M replicon type. The dissemination of KPC-2-producing K.pneumoniae in Bulgaria is mainly due to the sustained spread of successful ST15 clone and to a lesser extent of ST76 clone. This is the first report of OXA-48 producing ST101 K. pneumoniae in Bulgaria.