Document Type : Original Articles
Authors
1
Advanced Eye Centre, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
2
Advanced Eye Centre, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India.
3
Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India.
Abstract
Background and Purpose: Fungal Keratitis (FK) is a sight-threatening corneal infection resulting in monocular blindness. FK occurs more frequently in warm, humid tropical and subtropical regions, particularly those with an agriculture-based economy. The present study aims to check the spectrum of organisms causing FK and analyze the associated clinical features. Antifungal susceptibility patterns also determined with isolated organisms in a tertiary care center in North India.
Materials and Methods: This study was conducted on suspected FK cases recruited from January 2020 through December 2023 in the Advanced Eye Centre (AEC) Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh. The routine mycological laboratory data, including direct microscopy (KOH mount) and culture on Sabouraud’s Dextrose agar media (SDA), were collected. The clinical data and etiological factors were analysed by retrieving medical records. Further, the preserved isolates were subjected to antifungal susceptibility testing as per the Clinical and Laboratory Standards Institute (CLSI) broth microdilution method (M38-A2) for a panel of antifungals, including VRCZ (voriconazole), ITRA (itraconazole), PSCZ (posaconazole), LLCZ (luliconazole), MCZ (miconazole), KTZ (ketoconazole), AMB (amphotericin-B), NTM (natamycin), and TFH (terbinafine-hydrochloride).
Results: Of a total of 2891 suspected cases, 677 were found to be positive by either microscopy or culture. Of the 677 positive cases, 470 were culture-positive, 383 (56.57%) were both microscopy as well as culture-positive, 206 (30.42%) were culture-negative but microscopy-positive, and 87 (12.85%) were culture-positive but microscopy-negative.
In the geographical zones from , Punjab was leading with 39.29% of cases, followed by Haryana (26.14%), Uttar Pradesh (14.33%), and Himachal Pradesh (14.03%).
Aspergillus spp. was found to be the predominant etiologic agent accounting for (N=198/470) 42.12%, followed by Fusarium spp. (N=173/470) 36.80%, dematiaceous fungi (N=71/470) 15.10%. Clinical details of all 677 patients were successfully retrieved and found that vegetative trauma was the major associated etiological factor causing FK. Other etiological factors involved animal tails, dust, insects, foreign bodies, chemicals, or iron piece injuries. AFST results revealed that VRCZ, ITRA, and LLCZ exhibit low MIC values against Aspergillus spp. and Fusarium spp. VRCZ exhibits a median MIC range of 0.25µg/ml among Aspergillus spp. and 0.5µg/ml among Fusarium spp. and the dematiaceous group of fungi.
Conclusion: Aspergillus spp. represents the predominant etiology causing FK, followed by Fusarium spp., but dematiaceous fungi seem to pose a significant threat in causing FK. In-vitro susceptibility results revealed that with VRCZ, LLCZ can also be a promising antifungal drug for the treatment of FK.
Keywords
Subjects
