July 2019
Volume 60, Issue 9
Open Access
ARVO Annual Meeting Abstract  |   July 2019
In vitro susceptibility of Staphylococcus aureus and Pseudomonas aeruginosa to a novel fluoroquinolone
Author Affiliations & Notes
  • Alejandro Arboleda
    Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida, United States
  • Heather Durkee
    Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida, United States
  • Jorge Maestre-Mesa
    Ocular Microbiology Laboratory, Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida, United States
  • Maribel Hernandez
    Ocular Microbiology Laboratory, Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida, United States
  • Mariela Aguilar
    Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida, United States
  • Harry Flynn
    Anne Bates Leach Eye Hospital, Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida, United States
  • Jean-Marie Parel
    Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida, United States
    Anne Bates Leach Eye Hospital, Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida, United States
  • Darlene Miller
    Ocular Microbiology Laboratory, Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida, United States
    Anne Bates Leach Eye Hospital, Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida, United States
  • Footnotes
    Commercial Relationships   Alejandro Arboleda, None; Heather Durkee, None; Jorge Maestre-Mesa, None; Maribel Hernandez, None; Mariela Aguilar, None; Harry Flynn, None; Jean-Marie Parel, None; Darlene Miller, None
  • Footnotes
    Support  Financial support was provided by the University of Miami Scientific Awards Committee Interdisciplinary Team Science Pilot Award (UM SAC 2016-17), Florida Lions Eye Bank and Beauty of Sight Foundation, Edward D and Janet K Robson Fund, NIH Center Grant P30EY14801, Research to Prevent Blindness, Henri and Flore Lesieur Foundation (JMP), and Drs Raksha Urs and Aaron Furtado
Investigative Ophthalmology & Visual Science July 2019, Vol.60, 836. doi:https://doi.org/
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    • Get Citation

      Alejandro Arboleda, Heather Durkee, Jorge Maestre-Mesa, Maribel Hernandez, Mariela Aguilar, Harry Flynn, Jean-Marie Parel, Darlene Miller; In vitro susceptibility of Staphylococcus aureus and Pseudomonas aeruginosa to a novel fluoroquinolone. Invest. Ophthalmol. Vis. Sci. 2019;60(9):836. doi: https://doi.org/.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) are the most common pathogens in keratitis. Increased prevalence of antibiotic-resistant strains pose a treatment challenge for physicians. Delafloxacin is a new fluoroquinolone recently approved by the FDA for treatment of methicillin-resistant S. aureus (MRSA), methicillin-sensitive S. aureus (MSSA) and P. aeruginosa infections. The purpose of this study was to evaluate the in vitro efficacy of delafloxacin compared to commonly prescribed fluoroquinolones against isolates of MRSA, MSSA, and P. aeruginosa recovered from patients with ocular surface disease.

Methods : 36 MRSA, 27 MSSA, and 51 P. aeruginosa isolates recovered from patients were included in the study. Antibiotic susceptibility testing to delafloxacin, ciprofloxacin, levofloxacin, and moxifloxacin was performed using a combination of Epsilometer tests (E-tests) and VITEK2 tests (Biomerieux). Minimum inhibitory concentration (MIC) breakpoints were determined based on CLSI standards.

Results : Percent susceptibility of MRSA, MSSA, and P. aeruginosa to delafloxacin was found to be 75%, 88%, and 100%, respectively. Percent susceptibility of MRSA, MSSA, and P. aeruginosa to commonly-prescribed fluoroquinolones was 36%, 82%, and 100%, respectively. For the MRSA strains, the MIC90 (ug/ml) and MIC50 (ug/ml) for delafloxacin were 1.0 and 0.19, while the MIC90 and MIC50 for commonly-prescribed fluoroquinolones was 8, except for levofloxacin with a MIC50 of 4. Similarly, MSSA isolates had MIC90 and MIC50 for delafloxacin of 0.2 and 0.002, while MIC90 and MIC50 of the commonly-prescribed fluoroquinolones were 4 and 0.5. Agreement between delafloxacin and commonly-prescribed fluoroquinolones for MRSA, MSSA, and P. aeruginosa was 55%, 94%, and 100%, respectively.

Conclusions : Ocular MRSA, MSSA, and P. aeruginosa strains demonstrated mixed in vitro susceptibility to delafloxacin. Delafloxacin demonstrated excellent in vitro efficacy against P. aeruginosa strains. Although more MRSA strains were inhibited by delafloxacin at lower MICs compared to current ocular fluoroquinolones, the in vitro efficacy was less than 80%. In vitro efficacy for MSSA isolates was less than 90%. Delafloxacin may hold promise in treating P. aeruginosa infections, but provide similar in vitro coverage for MRSA and MSSA as current ocular fluoroquinolones and should be embraced with caution.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.

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