In vitro activity of delafloxacin against bacterial isolates from osteoarticular and skin infections in Buenos Aires, Argentina

In vitro activities of delafloxacin, ciprofloxacin and levofloxacin were evaluated by epsilometric and disk diffusion methods against 181 bacterial isolates recovered from bone and skin infections. Isolates included were 84 Staphylococcus aureus (40 MRSA and 44 MSSA), 46 coagulase-negative staphylococci (CNS), 23 Klebsiella pneumoniae and 28 Pseudomonas aeruginosa. The MIC50/MIC90(mg/l) for delafloxacin, ciprofloxacin and levofloxacin, respectively, were: MRSA, 0.004/0.064, 0.25/16 and 0.125/4; MSSA, 0.002/0.004, 0.125/0.25 and 0.125/0.25; CNS, 0.008/0.25, 0.125/ >32 and 0.25/ >32; K. pneumoniae, 4/ >32, >32/ >32 and16/ >32; P. aeruginosa, 1/ >32, 0,5/ >32 and 4/ >32. Susceptibilities for delafloxacin, ciprofloxacin and levofloxacin, respectively, were: MRSA, 97.5%, 82.5% and 82.5%; MSSA, 97.7%, 95.5% and 95.5%; CNS, 93.5%, 63.0% and 60.9%; K. pneumoniae, 21.7%, 26.1% and 43.5%; P aeruginosa, 35.7%, 53.6% and 42.8%. The disk diffusion and epsilometric methods were concordantfor evaluating in vitro susceptibility in staphylococci (categorical concordance of 98.8% for S. aureus and 91.3% for CNS). (c) 2021 Asociacion Argentina de Microbiologia. Published by Elsevier Espana, S.L.U. This is anopen access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).