Susceptibility of various corneal fungal isolates and Pseudomonas aeruginosa to contact lens disinfecting solutions

Authors

  • Antonio Pinna Department of Surgical, Microsurgical and Medical Sciences, University of Sassari, Sassari, Italy
  • Donatella Usai Department of Biomedical Sciences, Section of Clinical and Experimental Microbiology, University of Sassari, Sassari, Italy
  • Stefania Zanetti Department of Biomedical Sciences, Section of Clinical and Experimental Microbiology, University of Sassari, Sassari, Italy
  • Philip A Thomas Department of Microbiology, Institute of Ophthalmology, Joseph Eye Hospital, Tiruchirapalli, Tamil Nadu, India
  • Jayaraman Kaliamurthy Department of Microbiology, Institute of Ophthalmology, Joseph Eye Hospital, Tiruchirapalli, Tamil Nadu, India

DOI:

https://doi.org/10.3855/jidc.2756

Keywords:

contact lens-related keratitis, contact lens disinfectants, filamentous fungi, Pseudomonas aeruginosa, co-culture, susceptibility

Abstract

Introduction: We aimed to investigate the susceptibility of a combined inoculum of Pseudomonas aeruginosa and different fungal strains to 6 soft contact lens disinfectants.

Methodology: One corneal isolate of P. aeruginosa and 13 corneal fungal isolates (9 Aspergillus spp, 3 Fusarium spp, 1 Curvularia sp.) were used. The following solutions were tested: Arion Cronos, Complete RevitaLens, Dua Elite, Opti-Free Express, Regard, Oxysept Comfort, and Oxysept Comfort without catalase. The effect of the solutions was assessed on a combined inoculum of P. aeruginosa plus 1 fungal strain. Suspensions of P. aeruginosa and fungi were made in the solutions (1x106 colony-forming units/mL). After 1 hour (Arion Cronos only), 6, 8, and 24 hours, aliquots of suspension were removed and seeded on Luria-Bertani and Sabouraud agar plates.

Results: After 6 hours’ exposure, all the solutions but Dua Elite and Oxysept Comfort eradicated P. aeruginosa. Conversely, apart from 3% hydrogen peroxide-based Oxysept Comfort without catalase, which eradicated all the fungi tested after 6 hours, all the other solutions were partly ineffective at killing some of the fungal isolates, even after 24 hours’ exposure.

Conclusions: Most contact lens disinfectants may be ineffective if contact lens care systems become co-contaminated with P. aeruginosa and fungi. In our experiment, only exposure to 3% hydrogen peroxide without neutralizer for at least 6 hours was always able to kill a combined inoculum of P. aeruginosa and different fungal strains.

Author Biographies

Antonio Pinna, Department of Surgical, Microsurgical and Medical Sciences, University of Sassari, Sassari, Italy

Assistant Professor of Ophthalmology

Donatella Usai, Department of Biomedical Sciences, Section of Clinical and Experimental Microbiology, University of Sassari, Sassari, Italy

Researcher in Microbiology

Stefania Zanetti, Department of Biomedical Sciences, Section of Clinical and Experimental Microbiology, University of Sassari, Sassari, Italy

Full Professor in Microbiology

Philip A Thomas, Department of Microbiology, Institute of Ophthalmology, Joseph Eye Hospital, Tiruchirapalli, Tamil Nadu, India

Full Professor of Microbiology

Jayaraman Kaliamurthy, Department of Microbiology, Institute of Ophthalmology, Joseph Eye Hospital, Tiruchirapalli, Tamil Nadu, India

Assistant Professor of Microbiology

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Published

2013-03-14

How to Cite

1.
Pinna A, Usai D, Zanetti S, Thomas PA, Kaliamurthy J (2013) Susceptibility of various corneal fungal isolates and Pseudomonas aeruginosa to contact lens disinfecting solutions. J Infect Dev Ctries 7:261–268. doi: 10.3855/jidc.2756

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Section

Original Articles