Microbiological Spectrum, risk factors, and antifungal susceptibility of fungal keratitis in the Indore region of Central India

Purpose: To investigate the microbiological profile, risk factors, and antifungal susceptibility patterns of fungal pathogens isolated from fungal keratitis (FK) patients at a tertiary care center over a 1-year period in the Indore region of central India. Methods: A hospital-based prospective cross-sectional 1-year study was conducted on 100 clinically suspected FK cases. Fungal isolates were identified by conventional and molecular methods when needed. Spectra of organisms, demographic data, and risk factors were analyzed. A panel of nine antifungals, voriconazole (VRCZ), itraconazole (ITRA), posaconazole (PSCZ), natamycin (NTM), amphotericin B (AMB), luliconazole (LLCZ), miconazole (MCZ), ketoconazole (KTZ), and terbinafine hydrochloride (TFH), were determined using the broth microdilution method following CLSI guidelines. Results: Out of 100 suspected patients, 35 had proven FK, with 33 microscopy and culture-positive, and 2 were only microscopy-positive. The predominant isolates were Fusarium spp., 33.33% (n = 11), and Aspergillus spp., 33.33% (n = 11), including Aspergillus flavus 24.24% (n = 8), A. fumigatus 6.06% (n = 2), and one A. nidulans , followed by dematiaceous fungi, 21.21% (n = 7/33). The remaining four isolates belonged to different genera and species. Among all positive FK cases, risk factor analysis revealed that ocular trauma was the major risk factor, 54.54% (18/33), followed by usage of antimicrobials, 42.42% (14/33). Antifungal susceptibility testing of all triazoles showed similar MIC values across the isolates, including VRCZ, ITRA, and PSCZ, which ranged from 0.03 to 1 µg/ml. Newer drugs, including LLCZ and TFH, also exhibited lower MIC values across all isolates, LLCZ and TFH 0.001–0.06 µg/ml and 0.12–2 µg/ml, respectively. However, NTM and AMB had shown comparatively higher MICs. Conclusions: Fusarium spp. and Aspergillus spp. causing FK is a major concern in the Indore region. Triazoles exhibit superior in vitro antifungal activity against common FK pathogens, especially Aspergillus flavus and Fusarium spp.