June 2023
Volume 64, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2023
Phenotype and Genotype profiles of a unique cluster of Carbapenemase-Resistant Pseudomonas aeruginosa keratitis isolates
Author Affiliations & Notes
  • Jorge Maestre
    Ophthalmology, University of Miami School of Medicine, Miami, Florida, United States
  • Alexander Jesus Alfonso
    Ophthalmology, University of Miami School of Medicine, Miami, Florida, United States
  • Maribel Hernandez
    Ophthalmology, University of Miami School of Medicine, Miami, Florida, United States
  • Angel Suarez
    Ophthalmology, University of Miami School of Medicine, Miami, Florida, United States
  • Guillermo Amescua
    Ophthalmology, University of Miami School of Medicine, Miami, Florida, United States
  • Eduardo Alfonso
    Ophthalmology, University of Miami School of Medicine, Miami, Florida, United States
  • Darlene Miller
    Ophthalmology, University of Miami School of Medicine, Miami, Florida, United States
  • Harry W Flynn, Jr
    Ophthalmology, University of Miami School of Medicine, Miami, Florida, United States
  • Caroline Lieux
    Ophthalmology, University of Miami School of Medicine, Miami, Florida, United States
  • Jessica Castillo
    Ophthalmology, University of Miami School of Medicine, Miami, Florida, United States
  • Footnotes
    Commercial Relationships   Jorge Maestre None; Alexander Alfonso None; Maribel Hernandez None; Angel Suarez None; Guillermo Amescua None; Eduardo Alfonso None; Darlene Miller None; Harry Flynn, Jr None; Caroline Lieux None; Jessica Castillo None
  • Footnotes
    Support  None
Investigative Ophthalmology & Visual Science June 2023, Vol.64, 2327. doi:
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      Jorge Maestre, Alexander Jesus Alfonso, Maribel Hernandez, Angel Suarez, Guillermo Amescua, Eduardo Alfonso, Darlene Miller, Harry W Flynn, Jr, Caroline Lieux, Jessica Castillo; Phenotype and Genotype profiles of a unique cluster of Carbapenemase-Resistant Pseudomonas aeruginosa keratitis isolates. Invest. Ophthalmol. Vis. Sci. 2023;64(8):2327.

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

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Abstract

Purpose : To characterize a series of multidrug resistant, carbapenem-resistant Pseudomonas aeruginosa isolates recovered from patients presenting with keratitis at Bascom Palmer Eye Institute (BPEI) between June-December 2022. All were recovered from community patients with compromised cornea and ocular surface disorders (ulcer/keratitis, n=3), recurrent corneal erosion (n=1), failed graft (n=1) and Scleromalacia performants (n=1).

Methods : We used a combination of conventional and molecular techniques to characterize the 6 necrotizing Pseudomonas aeruginosa isolates. Phenotype and resistotype profiles were determined using the Vitek2 automated system. Resistance to selecting antibiotics was further confirmed with MTS gradient diffusion method (GD). The Carbapenemase resistome was determined using standard PCR and sequencing to screen for the presence of Carbapenemase-encoding genes (blaIMP, blaVIM, blaNDM, blaGES). Additionally, the Type III secretion profile -cytotoxic vs invasive was investigated with a multiplex PCR assay for effector genes: ExoU, ExoS, ExoT, and ExoY.

Results : All isolates were identified as Pseudomonas aeruginosa (with a biochemical fingerprint of >99%). The MDR (multidrug resistant profile/resistotype) included resistance (MICs ug/ml) to 4 classes of antibiotics: aminoglycosides (amikacin->=64, gentamicin->/=16, tobramycin->/=16); cephalosporins (ceftazidime->/=64, cefepime->/=64), fluoroquinolones (ciprofloxacin->/=4, levofloxacin->/=8) and carbapenemases (meropenem-8). Carbapenemase resistance was further confirmed using MTS strips: imipenem (12-16 ug/ml) and meropenem (6-16 ug/ml. Genomic resistance was mediated by the unique combination of Carbapenemase-resistance genes VIM-80 and GES-9 detected in all 6 isolates. All strains were classified as “cytotoxic” (ExoU+/S-). Two-thirds (4/6) of patients had therapeutic surgeries.

Conclusions : This group of cytotoxic, MDR-P. aeruginosa isolates were resistant to all commonly used ocular drug for Pseudomonas keratitis. The high-level pan antibiotic resistance correlated with the poor patient outcomes.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.

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