Fungal keratitis (FK) is recognized as a stubborn ocular condition, caused by intense fungal invasiveness and heightened immune reaction. The glycosaminoglycan chondroitin sulfate exhibits properties of immunomodulation and tissue regeneration. In prior investigations, oxidized chondroitin sulfate (OCS) ameliorated the prognosis of FK in murine models. To further improve the curative efficacy, we used the antifungal drug natamycin to functionalize OCS and prepared oxidized chondroitin sulfate-natamycin (ON) eye drops. The structure of ON was characterized by FTIR, UV-vis, and XPS, revealing that the amino group of natamycin combined with the aldehyde group in OCS through Schiff base reaction. Antifungal experiments revealed that ON inhibited fungal growth and disrupted the mycelium structure. ON exhibited exceptional biocompatibility and promoted the proliferation of corneal epithelial cells. Pharmacokinetic analysis indicated that ON enhanced drug utilization by extending the mean residence time in tears. In murine FK, ON treatment reduced the clinical score and corneal fungal load, restored corneal stroma conformation, and facilitated epithelial repair. ON effectively inhibited neutrophil infiltration and decreased the expression of TLR-4, LOX-1, IL-1β, and TNF-α. Our research demonstrated that ON eye drops achieved multifunctional treatment for FK, including inhibiting fungal growth, promoting corneal repair, enhancing drug bioavailability, and controlling inflammatory reactions.

OBJECTIVE: The purpose of this study was to assess the association between antifungal susceptibility as measured by minimum inhibitory concentration (MIC) and clinical outcomes in fungal keratitis.
METHODS: This pre-specified secondary analysis of the Mycotic Ulcer Treatment Trial II (MUTT II) involved patients with filamentous fungal keratitis presenting to Aravind Eye Hospitals in South India. Antifungal susceptibility testing for natamycin and voriconazole was performed on all samples with positive fungal culture results according to Clinical and Laboratory Standards Institute Guidelines. The relationship between MIC and clinical outcomes of best-corrected visual acuity, infiltrate or scar size, corneal perforation, need for therapeutic penetrating keratoplasty, and time to re-epithelialization were assessed.
RESULTS: We obtained MIC values from 141 patients with fungal keratitis. The most commonly cultured organisms were Aspergillus (46.81%, n = 66) and Fusarium (44.68%, n = 63) species. Overall, there was no association between antifungal MICs and clinical outcomes. Subgroup analysis revealed that among Fusarium-positive cases, higher voriconazole MIC was correlated with worse three-month best-corrected visual acuity (p = 0.03), increased need for therapeutic penetrating keratoplasty (p = 0.04), and time to re-epithelialization (p = 0.03). No significant correlations were found among Aspergillus-positive cases. There were no significant correlations found between natamycin MIC and clinical outcomes among organism subgroups.
CONCLUSIONS: Decreased susceptibility to voriconazole was associated with increased odds of requiring a therapeutic penetrating keratoplasty in Fusarium-positive cases. Susceptibility to natamycin was not associated with any of the measured outcomes.

OBJECTIVE: Fungal keratitis (FK) usually develops to a poor clinical prognosis due to the fungal invasion and excessive inflammatory reaction. In order to enhance the therapeutic effect of natamycin (NAT), we used the anti-inflammatory biological polysaccharide bletilla striata polysaccharide (BSP) combined with NAT to prepare a new eye drop -- oxidized bletilla striata polysaccharide-natamycin (OBN).
METHODS: UV-vis, FT-IR, and fluorescence spectroscopy were used to identify the synthesis of OBN. Biocompatibility of OBN was determined by CCK-8, scratch assay, and corneal toxicity test. RAW264.7 cells and C57BL/6 mice were stimulated with A. fumigatus and treated with PBS, OBN, or NAT. The anti-inflammatory activity of OBN was detected by RT-PCR and ELISA. In mice with FK, the clinical scores were used to evaluate the effect of OBN; HE staining was performed to assess the corneal pathological changes; MPO assay and immunofluorescence staining were used to investigate neutrophil infiltration.
RESULTS: OBN was synthesized by combining oxidized bletilla striata polysaccharide (OBSP) with NAT through Schiff base reaction. OBN did not affect cell viability at a concentration of 160 μg/mL in HCECs, RAW264.7 cells, and mouse corneas. OBN versus NAT significantly improved the prognosis of A. fumigatus keratitis by reducing disease severity, neutrophil infiltration, and expression of inflammatory factors in vivo. Additionally, OBN treatment down-regulated the mRNA and protein expression levels of inflammatory factors IL-1β, TNF-α, and IL-6 in RAW264.7 and mouse models.
CONCLUSIONS: OBN is a compound prepared by covalently linking OBSP to the imino group of NAT through Schiff base reaction. OBN treatment down-regulated inflammation and improved the prognosis of mice with A. fumigatus keratitis.

Fungal keratitis is a rare yet severe infection of the cornea. Fungal species distribution depends on the climate and socioeconomic status and can show regional variation. This retrospective single-center study was conducted at a tertiary eye care center and the collaborating Institute of Medical Microbiology in Switzerland. On investigating all fungal-positive corneal scrapings and contact lens assessments of patients with keratitis from January 2012 to December 2023, 206 patients were identified, of which 113 (54.9%) were female. The median age was 38 (IQR 29.8, [18-93]), and 154 (74.8%) applied contact lenses. The most commonly found pathogen was Candida spp., followed by Fusarium spp. Molds were 1.8 times more common than yeasts. Linear regression showed no significant increase or decrease in the infection rate over time (p = 0.5). In addition, 10 patients (4.9%) were found to have coinfections with Acanthamoeba, 11 (5.3%) with HSV-1, none with HSV-2, and 4 (1.9%) with VZV. This study provides a long-term overview of fungal-positive corneal scrapings and contact lens specimens of patients with fungal keratitis. Based on our results, coinfections with Acanthamoeba, HSV, and VZV are frequent, especially in patients wearing contact lenses. Thus, wearing contact lenses may facilitate coinfection in fungal keratitis.

Fungi belonging to Apiospora are phytopathogens not reported from human infections. Here, we report a case of keratitis due to Apiospora species in a carpenter who sustained a bamboo shrapnel injury to his eye when he was not wearing safety goggles. Thin hyaline septate hyphae were found on calcofluor white with potassium hydroxide (Calco-KOH) preparation of the scraping. A nonsporulating white mold grew from the corneal scrape, identified as A. rasikravindrae by Internal Transcribed Spacer (ITS) region sequencing. The patient improved with debridement and topical antifungal therapy. Educational interventions are needed to encourage safety goggles to prevent corneal injuries and blindness.

UNASSIGNED: The fungal unfolded protein response consists of a two-component relay in which the ER-bound sensor, IreA, splices and activates the mRNA of the transcription factor, HacA. Previously, we demonstrated that hacA is essential for Aspergillus fumigatus virulence in a murine model of fungal keratitis (FK), suggesting the pathway could serve as a therapeutic target. Here we investigate the antifungal properties of known inhibitors of the mammalian Ire1 protein both in vitro and in a treatment model of FK.
UNASSIGNED: The antifungal activity of Ire1 inhibitors was tested against conidia of several A. fumigatus isolates by a microbroth dilution assay and against fungal biofilm by XTT reduction. The influence of 4μ8C on hacA mRNA splicing in A. fumigatus was assessed through gel electrophoresis and qRT-PCR of UPR regulatory genes. The toxicity and antifungal profile of 4μ8C in the cornea was assessed by applying drops to uninfected or A. fumigatus-infected corneas 3 times daily starting 4 hours post-inoculation. Corneas were evaluated daily through slit-lamp imaging and optical coherence tomography, or at endpoint through histology or fungal burden quantification via colony forming units.
UNASSIGNED: Among six Ire1 inhibitors screened, the endonuclease inhibitor 4μ8C displayed the strongest antifungal profile with an apparent fungicidal action. The compound both blocked conidial germination and hyphal metabolism of A. fumigatus Af293 in the same concentration range that blocked hacA splicing and UPR gene induction (60-120 μM). Topical treatment of sham-inoculated corneas with 0.5 and 2.5 mM 4μ8C did not impact corneal clarity, but did transiently inhibit epithelialization of corneal ulcers. Relative to vehicle-treated Af293-infected corneas, treatment with 0.5 and 2.5 mM drug resulted in a 50% and >90% reduction in fungal load, respectively, the latter of which corresponded to an absence of clinical signs of infection or corneal pathology.
UNASSIGNED: The in vitro data suggest that 4μ8C displays antifungal activity against A. fumigatus through the specific inhibition of IreA. Topical application of the compound to the murine cornea can furthermore block the establishment of infection, suggesting this class of drugs can be developed as novel antifungals that improve visual outcomes in FK patients.

UNASSIGNED: Keratitis caused by Lasiodiplodia theobromae is rare and typically associated with a poor prognosis. Current literature lacks sufficient evidence on effective management of patients with this condition.
METHODS: A 74-year-old former agricultural worker presented with a red right eye, discomfort, and decreased visual acuity, progressing over three days without treatment. Examination revealed type 2 diabetes and a non-perforating, spiculated corneal abscess with a hypopyon in the right eye. Initial treatment included a triple antibiotic therapy and supportive care. Direct mycological examination identified numerous septate mycelial filaments. Antifungal treatment with natamycin and voriconazole, both topically and orally, was initiated. Cultures confirmed Lasiodiplodia theobromae. The patient showed significant improvement. Treatment continued for eight weeks, with a final visual acuity of 20/50 due to a stromal scar.
CONCLUSIONS: An extensive literature review conducted in November 2023, using databases such as PubMed and Google Scholar with the keywords \"lasiodiplodia\" and \"keratitis\" yielded no previous cases of this specific condition being managed solely with the combined use of natamycin and voriconazole. This antifungal combination is commonly included in most management protocols for fungal keratitis. Factors such as the use of corticosteroids and delayed diagnosis were noted to adversely affect the prognosis. This case and this systematic review underscores the potential for non-surgical management options in severe fungal keratitis.

Timely and effective diagnosis of fungal keratitis (FK) is necessary for suitable treatment and avoiding irreversible vision loss for patients. In vivo confocal microscopy (IVCM) has been widely adopted to guide the FK diagnosis. We present a deep learning framework for diagnosing fungal keratitis using IVCM images to assist ophthalmologists. Inspired by the real diagnostic process, our method employs a two-stage deep architecture for diagnostic predictions based on both image-level and sequence-level information. To the best of our knowledge, we collected the largest dataset with 96,632 IVCM images in total with expert labeling to train and evaluate our method. The specificity and sensitivity of our method in diagnosing FK on the unseen test set achieved 96.65% and 97.57%, comparable or better than experienced ophthalmologists. The network can provide image-level, sequence-level and patient-level diagnostic suggestions to physicians. The results show great promise for assisting ophthalmologists in FK diagnosis.

UNASSIGNED: To report a rare case of fungal keratitis caused by Cryptococcus neoformans, highlighting its unique morphological features using in vivo confocal microscopy (IVCM).
UNASSIGNED: This was a retrospective case report. A 66-year-old man presented with foreign body sensation and blurred vision in his left eye for over 10 months.
UNASSIGNED: His best-corrected visual acuity was 20/20. Slit-lamp examination revealed a gray-white lesion approximately 4-5 mm in the superficial layer of the central cornea without epithelial defects. The IVCM images revealed numerous round or round-like pathogens, each with a central highly reflective body surrounded by a dark ring, ranging in size from 5 to 30 µm, and to a maximum of 85 µm, observed in the corneal epithelium and superficial stroma. No obvious inflammatory cell infiltration was observed in the lesions or endothelium. C. neoformans infection was confirmed. The round pathogens completely disappeared after 8 weeks of treatment with topical amphotericin B and voriconazole eye drops.
UNASSIGNED: Fungal keratitis caused by C. neoformans is rare and easily overlooked due to atypical clinical signs and symptoms. This case reports the unique morphological features of C. neoformans in the cornea using IVCM for the first time, facilitating rapid, noninvasive auxiliary diagnosis of C. neoformans keratitis and treatment follow-up.

Aim: This study focuses on the development of a Caspofungin liposome for efficient ocular delivery by enhancing corneal penetration. Method: Quality by design (QbD) approach was adopted to identify critical factors that influence final liposomal formulation. The liposome developed using thin film hydration after optimization was subjected to characterization for physicochemical properties, irritation potential and corneal uptake. Results: The numerical optimization suggests an optimal formulation with a desirability value of 0.706, using CQAs as optimization goals with 95% prediction intervals. The optimized formulation showed no signs of irritation potential along with observation of significant corneal permeation. Conclusion: The liposomal formulation increased the permeability of Caspofungin, which could enhance the efficacy for the treatment of conditions, like fungal keratitis.
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