Ineffectiveness of intrastromal voriconazole for filamentous fungal keratitis
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Published on: November 12, 2015
Masanori Niki1, Hiroshi Eguchi1, Yuki Hayashi1
1Department of Ophthalmology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima-shi, Japan.
Purpose:
The purpose of this study is to describe the ineffectiveness of intrastromal voriconazole injection for filamentous fungal keratitis by contrasting the effectiveness for yeast keratitis.
Methods:
We examined seven fungal keratitis patients prospectively. All yeast was identified by molecular phylogenetic analyses of the chromosomal regions coding for the D1/D2 domain of the large-subunit 26S ribosomal RNA gene. All filamentous fungi were identified by the sequencing of internal transcribed spacers of the ribosomal DNA gene regions. Approximately 0.1 mL of voriconazole diluted with saline to 1.0% was injected with a 30-gauge needle inserted obliquely into the three to five clear cornea sites around the abscess. All subjects were administered natamycin ointment and oral itraconazole. When needed, intravenous micafungin, voriconazole, and/or intracameral voriconazole were added. Clinical courses were observed by the slit lamp microscope. Histopathology was examined when the corneas were removed.
Results:
All cases that were caused by yeast healed quickly after injections. Two cases of keratitis caused by Fusarium, and one case caused by Aspergillus, did not heal completely. In the Fusarium cases, additional antifungal medications (3.0% topical voriconazole and intravenous injection of micafungin) were needed. After optical penetrating keratoplasty in one of the cases, fungi were found in the deep stroma of the removed cornea. In the case of Aspergillus keratitis, pathological findings also showed fungi deep in the stroma of the removed cornea and the keratitis recurred after therapeutic penetrating keratoplasty.
Conclusion:
Intrastromal voriconazole injection is successful in treating yeast keratitis. However this is not the case for filamentous fungal keratitis.
Insights
Intrastromal voriconazole injection effectively treats yeast keratitis but is ineffective for filamentous fungal keratitis, such as Fusarium and Aspergillus infections. Further treatment is often required for filamentous cases.
Area of Science:
- Ophthalmology
- Mycology
- Infectious Diseases
Background:
- Fungal keratitis is a serious eye infection that can lead to vision loss.
- Voriconazole is a broad-spectrum antifungal agent used to treat various fungal infections.
- Intrastromal injection is a method of drug delivery directly into the cornea.
Purpose of the Study:
- To evaluate the effectiveness of intrastromal voriconazole injection for filamentous fungal keratitis.
- To compare its efficacy against yeast keratitis.
Main Methods:
- Prospective examination of seven fungal keratitis patients.
- Identification of yeast and filamentous fungi using molecular phylogenetic and DNA sequencing methods.
- Intrastromal injection of 1.0% voriconazole, supplemented with topical/oral/intravenous antifungals as needed.
Main Results:
- Yeast keratitis cases resolved rapidly following intrastromal voriconazole injections.
- Filamentous fungal keratitis (Fusarium, Aspergillus) showed incomplete healing.
- Fungal elements were found deep in the corneal stroma in non-healing filamentous cases, necessitating further interventions like keratoplasty.
Conclusions:
- Intrastromal voriconazole injection is a successful treatment for yeast keratitis.
- This injection method is not sufficiently effective for treating filamentous fungal keratitis, indicating limitations in drug penetration or activity against these fungi.
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