Effect of Oral Voriconazole on Fungal Keratitis in the Mycotic Ulcer Treatment Trial II (MUTT II): A Randomized Clinical Trial

Overview of Mycotic Keratitis

ABSTRACT

Keratomycosis is a serious corneal infection associated with high ocular morbidity that can lead to severe vision loss. It is estimated to affect more than 1 million patients annually, most commonly occurring in tropical climates, and represents a growing threat to patients worldwide. Despite aggressive medical management, fungal infections have a higher rate of perforation requiring surgical intervention compared with other infectious etiologies. Early diagnosis and appropriate treatment are keys to preserving vision and saving patients' eyes.Timely diagnosis of fungal keratitis helps minimize corneal damage and scarring and increases the likelihood of a favorable outcome. Studies have shown that correct identification of fungal infections is often delayed up to 2 to 3 weeks after initial presentation. This leads to incorrect or ineffective treatment for many patients. Diagnostic techniques explored in this study include corneal scrapings with staining and culture, visualization with in vivo confocal microscopy, molecular diagnostic techniques including polymerase chain reaction, and recently developed omics-based technologies.Treatment of fungal keratitis begins with topical antifungals. Medical management has been proven to be effective, but with limitations including poor drug penetration and low bioavailability. Cases that do not respond to topical therapy require more invasive and novel treatments to control the infection. We review the clinical trials that have shaped current practice patterns, with focus on the efficacy of topical natamycin as the primary therapy for filamentous fungal keratitis. We explore additional management strategies such as localized intrastromal and intracameral injections of antifungal medications, photodynamic therapy, and surgical intervention.

Favorable outcome of Lasiodiplodia theobromae keratomycosis : a clinical case and systematic review

BACKROUD

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.

CASE PRESENTATION

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.

CONCLUSION

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.

Fusarium Keratitis on the Rise - a Clinical Review

Fungal keratitis due to Fusarium species is a rare but serious ocular disease. Due to its rapid progression, often late diagnostic confirmation as well as limited topical treatment options, this is potentially sight threatening. Increasing contact lens use and global climate change have been suggested to be factors leading to an increase in cases of fusarium keratitis, even in regions with moderate climate. Early recognition and initiation of antimycotic treatment, as well as early surgical treatment by penetrating keratoplasty are decisive for the outcome.

Treatment Strategies for Filamentous Fungi Keratitis

INTRODUCTION

This research aims to describe clinical findings, epidemiology and treatment outcomes in patients with filamentous fungi keratitis of a tertiary centre in Germany over a 7-year period and to compare the efficacy of different antifungal treatments and the effect of additive topical steroids.

METHODS

This retrospective study included 25 eyes of 23 patients from October 2013 to December 2020 with cultural isolates of filamentous fungi and corresponding keratitis. Best-corrected visual acuity (BCVA), clinical signs, symptoms, risk factors and outcome were extracted from medical records.

RESULTS

Improvement of BVCA was noted in 68% of eyes. Mean BCVA of the study population increased from 0.75 logMAR [median 0.40, standard deviation (SD) 0.82, range 0-2.3] to 0.48 logMAR (median 0.10, SD 0.88, range - 0.1 to 3). The most commonly used antifungal topical treatment was a combination of natamycin 5% and voriconazole 2% (44% of eyes), followed by voriconazole 2% in 36% of cases. An antiinflammatory topical steroid was applied in 52%. In 16% of the eyes, penetrating keratoplasty (pKP) was performed.

CONCLUSION

Diagnosis of filamentous fungi keratitis is often difficult or delayed. Outcomes can be poor even with intensive treatment because of high resistance to common antifungals. Access to natamycin 5% seems to lead to favourable outcomes in filamentous fungi keratitis.

Infectious Keratitis in Patients Over 65: A Review on Treatment and Preserving Eyesight

Infectious keratitis (IK) represents a significant global health concern, ranking as the fifth leading cause of blindness worldwide despite being largely preventable and treatable. Elderly populations are particularly susceptible due to age-related changes in immune response and corneal structure. However, research on IK in this demographic remains scarce. Age-related alterations such as increased permeability and reduced endothelial cell density further compound susceptibility to infection and hinder healing mechanisms. Additionally, inflammaging, characterized by chronic inflammation that develops with advanced age, disrupts the ocular immune balance, potentially exacerbating IK and other age-related eye diseases. Understanding these mechanisms is paramount for enhancing IK management, especially in elderly patients. This review comprehensively assesses risk factors, clinical characteristics, and management strategies for bacterial, viral, fungal, and acanthamoeba keratitis in the elderly population, offering crucial insights for effective intervention.

A double-masked, sham-controlled trial of rose bengal photodynamic therapy for the treatment of fungal and acanthameoba keratitis: Rose Bengal Electromagnetic Activation with Green Light for Infection Reduction (REAGIR) Study

Background

Infectious keratitis secondary to fungus or acanthamoeba often has a poor outcome despite receiving the best available medical therapy. In vitro Rose Bengal Photodynamic therapy (RB-PDT) appears to be effective against fungal and acanthamoeba isolates.22,23 In one published series RB-PDT reduced the need for therapeutic penetrating keratoplasty in severe bacterial, fungal, and acanthameoba keratitis not responsive to medical therapy.

Methods

This international, randomized, sham and placebo controlled 2-arm clinical trial, randomizes patients with smear positive fungal and acanthameoba and smear negative corneal ulcers in a 1:1 fashion to one of two treatment arms: 1) Topical antimicrobial plus sham RB-PDT or 2) Topical antimicrobial plus RB-PDT.

Discussion

We anticipate that RB-PDT will improve best spectacle corrected visual acuity and also reduce complications such as corneal perforation and the need for therapeutic penetrating keratoplasty. This study will comply with the NIH Data Sharing Policy and Policy on the Dissemination of NIH-Funded Clinical Trial Information and the Clinical Trials Registration and Results Information Submission rule. Our results will be disseminated via clinicaltrials.gov website, meetings, and journal publications. Our data will also be available upon reasonable request.

Trial Registration

NCT, NCT05110001, Registered November 5, 2021. https://www.clinicaltrials.gov/study/NCT05110001.

Fungal Keratitis, Epidemiology and Outcomes in a Tropical Australian Setting

BACKGROUND

Fungal keratitis is an ophthalmic emergency that can cause visual impairment and blindness. We reviewed the epidemiology and clinical features of fungal keratitis in a tropical Australian setting.

OBJECTIVES

To document the clinical and microbiological characteristics of fungal keratitis in an Australian tropical setting.

METHODS

A retrospective cohort study of patients with fungal keratitis from October 2014 to December 2022 was conducted at Royal Darwin Hospital, Northern Territory, Australia. We reviewed all patients with culture-proven fungal keratitis and their outcomes.

RESULTS

There were 31 patients identified. Aboriginal and Torres Strait Islander (ATSI) patients were of a significantly younger median age (28 years) compared to non-ATSI patients (42 years), and they also presented later to health care. Contact lens use and ocular trauma were the most common predisposing factors. Most patients presented with a corneal infiltrate and corneal epithelial defect, and the central visual axis was affected in 54% of patients. Curvularia spp. and Fusarium spp. were the commonest causative fungi (39% and 30% respectively).

CONCLUSIONS

Our series is different and reveals a wider range of fungal species identified over the 7 years of the study, in particular, a range of Curvularia spp. were detected. Access to eye health services in rural and remote settings is important, particularly for ATSI patients, as morbidity remains high.

Fusarioid keratitis and other superficial infections: A 10-years prospective study from Northeastern Brazil

BACKGROUND

Fusarium and allied genera (fusarioid) species are common colonizers of roots and aerial plant parts, or act as phytopathogens in forestry and horticultural or grain crops. However, they can also cause a wide range of infections in humans, including onychomycosis, cutaneous and invasive infections. Fusarioid keratitis is characterized by an infection of the cornea with a suppurative and ulcerative appearance, which may cause damage to vision and permanent blindness. The aim of the present study was to investigate the prevalence of fusarioid species, biofilm formation and antifungal susceptibility profiling of clinical isolates recovered from patients with keratitis and dermatomycoses.

METHODOLOGY/PRINCIPAL FINDINGS

The study was performed between March, 2012-December, 2022. Demographic, clinical and epidemiological data of patients were also collected. In the present study, most of the patients with keratitis were male (74%), had a median age of 42 years old, worked with plant material or debris and 26% of them reported eye trauma. Regarding dermatomycosis, most of patients were female and exhibited toenail lesions. Forty-seven isolates belonged to the genus Neocosmospora (78.33%), nine to the Fusarium fujikuroi (15%) and four to the Fusarium oxysporum (6.66%) species complexes. Several strains were moderate biofilm producers, specifically among Fusarium annulatum. Most strains showed increased MICs to amphotericin B and ketoconazole and low MICs to itraconazole. MICs ranged from 0.25 to 16 μg/mL for amphotericin B, 0.0625 to >16 μg/mL for ketoconazole and 0.125 to 8 for itraconazole.

CONCLUSIONS/SIGNIFICANCE

It is possible to conclude that fusarioid keratitis in Northeastern Brazil is an important and neglected disease, given the high number of cases, increased need for keratoplasty and poor outcome of the disease.

The differential virulence of Fusarium strains causing corneal infections and plant diseases is associated with accessory chromosome composition

Fusarium oxysporum is a cross-kingdom pathogen. While some strains cause disseminated fusariosis and blinding corneal infections in humans, others are responsible for devastating vascular wilt diseases in plants. To better understand the distinct adaptations of F. oxysporum to animal or plant hosts, we conducted a comparative phenotypic and genetic analysis of two strains: MRL8996 (isolated from a keratitis patient) and Fol4287 (isolated from a wilted tomato [Solanum lycopersicum]). In vivo infection of mouse corneas and tomato plants revealed that, while both strains cause symptoms in both hosts, MRL8996 caused more severe corneal ulceration and perforation in mice, whereas Fol4287 induced more pronounced wilting symptoms in tomato. In vitro assays using abiotic stress treatments revealed that the human pathogen MRL8996 was better adapted to elevated temperatures, whereas the plant pathogen Fol4287 was more tolerant of osmotic and cell wall stresses. Both strains displayed broad resistance to antifungal treatment, with MRL8996 exhibiting the paradoxical effect of increased tolerance to higher concentrations of the antifungal caspofungin. We identified a set of accessory chromosomes (ACs) and protein-encoding genes with distinct transposon profiles and functions, respectively, between MRL8996 and Fol4287. Interestingly, ACs from both genomes also encode proteins with shared functions, such as chromatin remodeling and post-translational protein modifications. Our phenotypic assays and comparative genomics analyses lay the foundation for future studies correlating genotype with phenotype and for developing targeted antifungals for agricultural and clinical uses.

Microbial keratitis and its management at a rural centre: achieving success with limited resources

PURPOSE

Microbial keratitis is a sight-threatening condition with a higher incidence in agrarian populations. In countries with a high indigent population, due to financial and other constraints, patients prefer to seek therapy locally rather than travel to advanced centres. The aim of this study is to describe the epidemiology, clinical characteristics, and outcomes of 60 consecutive patients with microbial keratitis managed at a rural centre.

METHODS

Descriptive case series. All patients clinically diagnosed with infectious keratitis were included. Corneal scrapings were obtained and microbiological identification was done by Gram stain. Anti-microbial therapy was commenced based on smear findings and the patients were followed up till disease resolution.

RESULTS

Sixty eyes of 60 patients were diagnosed with microbial keratitis in the study period. The mean age was 47.43 ± 18.69 years. Male:female ratio was 47:53. Risk factors included ocular trauma in the majority of patients (46/60; 76.7%). Microorganisms were identified on 75.6% of smears, with fungal filaments (65.4%) being the most common. Ulcers were central in over half (32/60; 53.3%), and > 3 mm in diameter in over three-fourths (81.6%) of patients. Forty-four patients (73.3%) achieved treatment success whereas 16/60 (26.6%) required referral to our tertiary-eye care facility for management. The median time to resolution was 14 days (IQR 10-26 days).

CONCLUSION

Our series demonstrates the feasibility of microbiology-guided therapy in microbial keratitis by ophthalmologists at the secondary rural eye-care level. Two-thirds of the patients could be successfully managed at the rural centre and only severe cases needed a referral to tertiary centres.

Physiochemical Characterization of Lipidic Nanoformulations Encapsulating the Antifungal Drug Natamycin

Natamycin is a tetraene polyene that exploits its antifungal properties by irreversibly binding components of fungal cell walls, blocking the growth of infections. However, topical ocular treatments with natamycin require frequent application due to the low ability of this molecule to permeate the ocular membrane. This limitation has limited the use of natamycin as an antimycotic drug, despite it being one of the most powerful known antimycotic agents. In this work, different lipidic nanoformulations consisting of transethosomes or lipid nanoparticles containing natamycin are proposed as carriers for optical topical administration. Size, stability and zeta potential were characterized via dynamic light scattering, the supramolecular structure was investigated via small- and wide-angle X-ray scattering and 1H-NMR, and the encapsulation efficiencies of the four proposed formulations were determined via HPLC-DAD.

Locality is the strongest predictor of expert performance in image-based differentiation of bacterial and fungal corneal ulcers from India

PURPOSE

This study sought to identify the sources of differential performance and misclassification error among local (Indian) and external (non-Indian) corneal specialists in identifying bacterial and fungal keratitis based on corneal photography.

METHODS

This study is a secondary analysis of survey data assessing the ability of corneal specialists to identify acute bacterial versus fungal keratitis by using corneal photography. One-hundred images of 100 eyes from 100 patients with acute bacterial or fungal keratitis in South India were previously presented to an international cohort of cornea specialists for interpretation over the span of April to July 2021. Each expert provided a predicted probability that the ulcer was either bacterial or fungal. Using these data, we performed multivariable linear regression to identify factors predictive of expert performance, accounting for primary practice location and surrogate measures to infer local fungal ulcer prevalence, including locality, latitude, and dew point. In addition, Brier score decomposition was used to determine experts' reliability ("calibration") and resolution ("boldness") and were compared between local (Indian) and external (non-Indian) experts.

RESULTS

Sixty-six experts from 16 countries participated. Indian practice location was the only independently significant predictor of performance in multivariable linear regression. Resolution among Indian experts was significantly better (0.08) than among non-Indian experts (0.01; P < 0.001), indicating greater confidence in their predictions. There was no significant difference in reliability between the two groups ( P = 0.40).

CONCLUSION

Local cornea experts outperformed their international counterparts independent of regional variability in tropical risk factors for fungal keratitis. This may be explained by regional characteristics of infectious ulcers with which local corneal specialists are familiar.

Validation of the C-DU(KE) Calculator as a Predictor of Outcomes in Patients Enrolled in Steroids for Corneal Ulcer and Mycotic Ulcer Treatment Trials

PURPOSE

The aim of this study was to validate the C-DU(KE) calculator as a predictor of treatment outcomes on a data set derived from patients with culture-positive ulcers.

METHODS

C-DU(KE) criteria were compiled from a data set consisting of 1063 cases of infectious keratitis from the Steroids for Corneal Ulcer Trial (SCUT) and Mycotic Ulcer Treatment Trial (MUTT) studies. These criteria include corticosteroid use after symptoms, visual acuity, ulcer area, fungal etiology, and elapsed time to organism-sensitive therapy. Univariate analysis was performed followed by multivariable logistic regressions on culture-exclusive and culture-inclusive models to assess for associations between the variables and outcome. The predictive probability of treatment failure, defined as the need for surgical intervention, was calculated for each study participant. Discrimination was assessed using the area under the curve for each model.

RESULTS

Overall, 17.9% of SCUT/MUTT participants required surgical intervention. Univariate analysis showed that decreased visual acuity, larger ulcer area, and fungal etiology had a significant association with failed medical management. The other 2 criteria did not. In the culture-exclusive model, 2 of 3 criteria, decreased vision [odds ratio (OR) = 3.13, P < 0.001] and increased ulcer area (OR = 1.03, P < 0.001), affected outcomes. In the culture-inclusive model, 3 of 5 criteria, decreased vision (OR = 4.9, P < 0.001), ulcer area (OR = 1.02, P < 0.001), and fungal etiology (OR = 9.8, P < 0.001), affected results. The area under the curves were 0.784 for the culture-exclusive model and 0.846 for the culture-inclusive model which were comparable to the original study.

CONCLUSIONS

The C-DU(KE) calculator is generalizable to a study population from large international studies primarily taking place in India. These results support its use as a risk stratification tool assisting ophthalmologists in patient management.

Recent Advances in Diagnosis and Treatment Approaches in Fungal Keratitis: A Narrative Review

Fungal keratitis represents a potentially sight-threatening infection associated with poor prognosis, as well as financial burden. Novel diagnostic methods include polymerase-chain-reaction (PCR)-based approaches, metagenomic deep sequences, in vivo confocal microscopy, and antifungal susceptibility testing. The ideal therapeutic approaches and outcomes have been widely discussed in recent times, with early therapy being of the utmost importance for the preservation of visual acuity, minimizing corneal damage and reducing the scar size. However, combination therapy can be more efficacious compared to monotherapy. Understanding the pathogenesis, early diagnosis, and prevention strategies can be of great importance. In this narrative, we discuss the recent progress that may aid our understanding of the diagnosis, treatment, and prevention of mycotic keratitis.

Fungal Keratitis: Diagnosis, Management, and Recent Advances

Fungal keratitis is one of the major causes of microbial keratitis that may lead to corneal blindness. Many problems related to diagnosis and therapy are encountered in fungal keratitis, including difficulty in obtaining laboratory diagnoses and the availability and efficacy of antifungal medications. Intensive and prolonged use of antifungal topical preparations may not be enough. The use of antifungal medications is considered the main treatment for fungal keratitis. It is recommended to start antifungal therapy after confirmation of the clinical diagnosis with a smear or positive cultures. Topical application of antifungal medications is a mainstay for the treatment of fungal keratitis; however, systemic, intra-stromal, or intra-cameral routes may be used. Therapeutic keratoplasty is the main surgical procedure approved for the management of fungal keratitis with good success rate. Intrastromal corneal injection of antifungal medications may result in steady-state drug levels within the corneal tissue and prevent intervals of decreased antifungal drug concentration below its therapeutic level. In cases of severe fungal keratitis with deep stromal infiltration not responding to treatment, intracameral injection of antifungal agents may be effective. Collagen cross-linking has been proposed to be beneficial for cases of fungal keratitis as a stand-alone therapy or as an adjunct to antifungal medications. Although collagen cross-linking has been extensively studied in the past few years, its protocol still needs many modifications to optimize UV fluence levels, irradiation time, and concentration of riboflavin to achieve 100% microbial killing.

Amniotic membrane transplantation combined with conjunctival flap covering surgery for the treatment of corneal perforations in fungal keratitis

Purpose

To investigate the efficiency of amniotic membrane transplantation (AMT) combined with conjunctival flap covering surgery (CFCS) for patients with corneal perforations in fungal keratitis (FK).

Methods

In this non-comparative, retrospective case series, 16 participants of corneal perforation in FK were successfully treated by a combination of multilayer AMT and bipedicle conjunctival flap with partial tenon's capsule. Corneal healing, recurrence of FK, visual acuity, and relevant complications were reported as outcome measures.

Results

Sixteen patients (13 male, 3 female) had a mean age of 58.8 ± 10.3 (range 29-72) years. The mean diameter of corneal perforation was 1.9 ± 0.7 (range 0.5-2.8) mm. Corneal perforations healed and all the patients preserved their eyeballs. During the 11.0 ± 4.4 (range 6-18) months of follow-up, there was no recurrence of FK in any of these cases. Visual acuity improved in 15 eyes (93.8 %) and remained unchanged in 1 patient (6.3 %) who had no light perception when first admitted. All 6 patients who accepted secondary keratoplasty showed improved best corrected visual acuity of more than 4 lines. The most frequently found fungi were Aspergillus species (6 of 16, 37.5 %) and Fusarium species (4 of 16, 25.0 %), followed by 1 Scedosporium apiospermum (1 of 16, 6.3 %).

Conclusions

Combination AMT with CFCS is a safe and effective surgery for patients with corneal perforations in FK, particularly where eye banks and fresh corneas are not available. This surgery could preserve the integrity of the eyeball and avoid the recurrence of FK. Besides, it provides a greater opportunity for further optical keratoplasty.

Challenges in the diagnosis and management of atypical fungal keratitis during the COVID-19 pandemic: a case series

Fungal keratitis is a time-sensitive ocular infection that often requires a high index of suspicion followed by intensive medical/surgical interventions to achieve a successful clinical outcome. COVID-19 pandemic-related restrictions, necessitated the modification of conventional protocols and guidelines associated with the treatment of keratomycosis. We report four cases of atypical fungal keratitis with poorly differentiated clinical characteristics. The challenges faced during their management were (1) the dilemma of clinically differentiating fungal (Scedosporium and Purpureocillium lilacinum) and bacterial keratitis; (2) treatment of Scedosporium and Trichosporon keratitis with natamycin monotherapy; (3) mixed infection of Candida albicans and Aureobasidium pullulans and continuing medications before rescraping the corneal ulcer against the recommended treatment guidelines; (4) phenotypic identification and differentiation among morphologically resembling fungi; and (5) decision making arising out of disparities between KOH and fungal culture results. Three patients responded well to conservative treatments. The fourth patient underwent therapeutic keratoplasty but was lost to follow-up due to travel-related pandemic restrictions. This case series seeks to broaden the clinician's knowledge of rare and emerging moulds as presumptive aetiologies of keratomycosis. It also intends to emphasize the significance of early microbiological investigations, (direct microscopy and culture), in resource-limited settings, for initiating empirical treatment for a better visual prognosis.

Repeated Intracameral Amphotericin B: A Safe Approach for Management of Fungal Anterior Chamber Reactivations After Therapeutic Penetrating Keratoplasty

PURPOSE

The aim of this study was to describe the safe use of repeated intracameral amphotericin B for anterior chamber reactivations after therapeutic penetrating keratoplasty for Fusarium solani keratitis.

METHODS

A 49-year-old woman monthly soft contact lens wearer with a history of overuse and swimming in her lenses presented with a red painful left eye. Her vision was 0.5 logMAR and there was a poorly demarcated corneal infiltrate. Although corneal scrapes and a corneal biopsy were negative, confocal microscopy showed fungal hyphae. After failure of medical treatment, therapeutic penetrating keratoplasty was performed. Fusarium solani sensitive to amphotericin was isolated. There was pan-azole resistance. The patient was managed with topical amphotericin B, and repeated anterior chamber reactivations were managed with intracameral amphotericin B 5 µg in 0.1 mL on 9 occasions over 5 months after sensitivities were known. Topical cyclosporine was used as the sole immunomodulator postoperatively, with no topical steroid use over the 4-year follow-up period.

RESULTS

There were no episodes of graft rejection and no endothelial, lenticular, or retinal toxicity. The best-corrected visual acuity is -0.1 logMAR and the endothelial cell count is 2160/mm 2 .

CONCLUSION

This report describes the safe and effective use of repeated intracameral amphotericin (cumulative 45 µg) in anterior chamber reactivations after therapeutic penetrating keratoplasty and highlights the role of fungal sensitivity in guiding treatment in refractory cases. It also demonstrated the successful use of topical cyclosporin as the sole postoperative immunomodulatory therapy despite repeated recurrence of infection and consequent increased inflammation in the postoperative period.

Corneal Culture and Antibiotic Susceptibility Results for Microbial Keratitis in the Mid-Atlantic Region of the United States, 2016 to 2020

OBJECTIVE

To examine the microbial distribution and antimicrobial susceptibility of culture-positive microbial keratitis at a large tertiary referral center in the mid-Atlantic region of the United States.

METHODS

Retrospective review of culture-positive microbial keratitis cases at the Wilmer Eye Institute from 2016 through 2020.

RESULTS

Of the 474 culture-positive microbial keratitis cases, most were bacterial (N=450, 94.9%), followed by fungal (N=48, 10.1%) and Acanthamoeba keratitis (N=15, 3.1%). Of the 450 bacterial isolates, 284 (69.5%) were gram-positive organisms, whereas 157 (28.4%) were gram-negative organisms. The most common bacterial species isolated was coagulase-negative Staphylococcus spp (N=154, 24.8%), and the most common gram-negative isolate was Pseudomonas aeruginosa (N=76, 12.3%). Among fungi, the most common isolates were Candida (N=25, 45.4%), whereas Fusarium (N=6, 10.9%) and Aspergillus (N=3, 5.5%) were less common. Of the 217 bacterial isolates tested for erythromycin susceptibility, 121 (55.7%; ∼60% of coagulase-negative staphylococci and corynebacteria tested) showed resistance to erythromycin.

CONCLUSIONS

Microbial keratitis in the Baltimore Mid-Atlantic region of the United States is most commonly caused by bacteria, with fungi and acanthamoeba being less common. Gram-positive bacterial infections predominate. Among fungal keratitis cases, Candida species are more commonly encountered than are filamentous species. Use of erythromycin as infection prophylaxis should be reexamined. Findings from our study may guide empiric treatment in this geographic region.

Eye fungal infections: a mini review

Ocular fungal infections annually affect more than one million individuals worldwide. The management of these infections is problematic, mainly due to the limited availability of effective antifungal agents. Thus, ocular infections are increasingly recognized as important causes of morbidity and blindness, especially keratitis and endophthalmitis. Thus, this review aims to demonstrate the importance of fungal eye infections through the description of the main related aspects, with emphasis on the treatment of these infections. For this purpose, a search for scientific articles was conducted in databases, such as Medline, published from 2000 onwards, addressing important aspects involving fungal eye infections. In addition, this work highlighted the limited therapeutic arsenal available and the severity associated with these infections. Thus, highlighting the importance of constantly updating knowledge about these pathologies, as it contributes to agility in choosing the available and most appropriate therapeutic alternatives, aiming at positive and minimally harmful results for that particular patient.

Oral voriconazole monotherapy for fungal keratitis: efficacy, safety, and factors associated with outcomes

Purpose

To provide preliminary data on the efficacy and safety of oral voriconazole (VCZ) as a primary treatment for fungal keratitis (FK).

Method

We performed a retrospective histopathological analysis of data on 90 patients with FK at The First Affiliated Hospital of Guangxi Medical University between September 2018 and February 2022. We recorded three outcomes: corneal epithelial healing, visual acuity (VA) improvement, and corneal perforation. Independent predictors were identified using univariate analysis, and multivariate logistic regression analysis was used to identify independent predictive factors associated with the three outcomes. The area under the curve was used to evaluate the predictive value of these factors.

Results

Ninety patients were treated with VCZ tablets as the only antifungal drug. Overall, 71.1% (n = 64) of the patients had extreme corneal epithelial healing, 56.7% (n = 51) showed an improvement in VA, and 14.4% (n = 13) developed perforation during treatment. Non-cured patients were more likely to have large ulcers (≥5 × 5 mm²) and hypopyon.

Conclusion

The results indicated that oral VCZ monotherapy was successful in the patients with FK in our study. Patients with ulcers larger than 5 × 5 mm² and hypopyon were less likely to respond to this treatment.

Monotherapy with topical Natamycin to treat Scedosporium keratomycosis: A rare case from Central India

Keratomycosis is common in Indian subcontinent. Diagnosis of the causal agent and successful management is a challenge for the clinician. Scedosporium is a rare fungus species, and it is relatively rare in causing keratomycosis. We report the case of a 29-year-old male who presented with complaints of redness, watering, and white lesion over his left eye. He sustained an injury in the left eye with vegetative matter. Corneal scraping was sent for potassium hydroxide staining and culture; fungal colony was seen in culture. Colony characters on Sabouraud dextrose agar and lactophenol cotton blue enabled a diagnosis of Scedosporium species. The patient was treated with topical Natamycin 5%, and complete resolution was seen at the end of 4 weeks. This case report highlights good response of keratitis caused by Scedosporium to topical Natamycin therapy.

Antimicrobial resistance in topical treatments for microbial keratitis: protocol for a systematic review and meta-analysis

INTRODUCTION

There is evidence for increased resistance against the antimicrobials used to treat keratitis. This review aims to provide global and regional prevalence estimates of antimicrobial resistance in corneal isolates and the range of minimum inhibitory concentrations (MIC) with their associated resistance breakpoints.

METHODS AND ANALYSIS

We report this protocol following Preferred Reporting Items for Systematic Review and Meta-Analyses Protocols guidelines. We will conduct an electronic bibliographic search in MEDLINE, EMBASE, Web of Science and the Cochrane Library. Eligible studies will report in any language data for the resistance or MIC for antimicrobials against bacterial, fungal or amoebic organisms isolated from suspected microbial keratitis. Studies that only report on viral keratitis will not be included. There will be no time restrictions on the date of publication. Screening for eligible studies, assessment of risk of bias and data extraction will be conducted by two reviewers independently, using predefined inclusion criteria and prepiloted data extraction forms. We will resolve disagreements between the reviewers by discussion and, if required, a third (senior) reviewer will arbitrate. We will assess the risk of bias using a tool validated in prevalence studies. The certainty of the evidence will be assessed using the Grades of Recommendation, Assessment, Development and Evaluation approach. Pooled proportion estimates will be calculated using a random-effects model. Heterogeneity will be assessed using the I2 statistic. We will explore differences between Global Burden of Disease regions and temporal trends.

ETHICS APPROVAL AND DISSEMINATION

Ethics approval is not required as this is a protocol for a systematic review of published data. The findings of this review will be published in an open-access, peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42023331126.

Fungal keratitis caused by Coniochaeta mutabilis – a case report

We present a rare case of recalcitrant fungal keratitis caused by Coniochaeta mutabilis, successfully managed with a course of oral, topical, intrastromal, and intracameral antifungals. A 57-year-old male on their fourth week of treatment for presumed left herpes simplex keratitis presented to clinic with severe left-sided foreign body sensation after gardening in his yard. On examination, a white corneal plaque was observed at 8 o'clock, shown to be a dense collection of fungal hyphae on confocal microscopy. Corneal cultures revealed yeast-like cells, initially identified as Kabatiella zeae by matching 100% identity with K. zeae strains CBS 767.71 and CBS 265.32 in BLASTn search using the internal transcribed spacer (ITS) sequence. Treated for over four months with topical amphotericin B and oral voriconazole without improvement, recourse to intrastromal and intracameral amphotericin B injections, coupled with the application of cyanoacrylate glue to the lesion and a bandage contact lens, led to eventual resolution. The patient subsequently underwent cataract surgery, achieving a BCVA of 20/20 in the eye. Surprisingly, upon further sequence analyses of combined ITS and large subunit ribosomal ribonucleic acid (LSU) and investigation of the K. zeae German strain CBS 767.71, the organism was revealed to be Coniochaeta mutabilis (formerly Lecythospora mutabilis). This means that the correct name for CBS 767.71 and CBS 265.32 is C. mutabilis and should be corrected in the GenBank record to avoid misleading identification in the future. This case also underscores the urgent unmet need for improved molecular diagnostic modalities in the care of corneal infections.

Identification of hub genes and pathways of ferroptosis in Fusarium keratitis by bioinformatics methods

Background

Fungal keratitis is a common blinding eye disease, and Fusarium is one of the main species that cause fungal keratitis. As is well known, oxidative stress plays an important role in Fusarium keratitis and it is also a significant initiating factor of ferroptosis. But the relationship between Fusarium keratitis and ferroptosis is currently unclear. This study aimed to speculate and validate potential ferroptosis-related genes in Fusarium keratitis using bioinformatics analysis, which provided ideas for further research on its specific mechanism and new targets for its treatment.

Methods

The microarray expression profiling dataset (GSE58291) came from Gene Expression Omnibus (GEO). The differentially expressed genes (DEGs) were obtained by the limma package of the R software. The DEGs were performed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. Then, the DEGs were intersected with the genes in the ferroptosis database. The top 5 hub genes were obtained by the protein-protein interaction (PPI) network analysis and the cytoHubba plug-in of Cytoscape software. The hub genes were subjected to GSEA analysis. Then we analyzed the immune infiltration of the samples by CIBERSORT and ssGSEA algorithm. Finally, we validated the mRNA of hub genes by qPCR.

Results

A total of 1,368 DEGs were identified and 26 ferroptosis-related DEGs were obtained. At the same time, ferroptosis-related pathways were enriched by GO and KEGG using DEGs. HMOX1, CYBB, GPX2, ALOX5 and SRC were obtained by the PPI network analysis and the cytoHubba plug-in of Cytoscape software. The iron metabolism and immune response related pathways were enriched using GSEA. They included hematopoietic cell lineage, lysosome and FC gamma R mediated phagocytosis. T cells follicular helper, monocytes, macrophages and mast cells might play an important role in Fusarium keratitis using analysis of immune infiltration. Finally, qPCR confirmed that the expression of HMOX1, CYBB, ALOX5 mRNA in the DON group was significantly elevated, while the expression of GPX2 were significantly decreased.

Conclusions

Ferroptosis may play an important role in Fusarium keratitis. HMOX1, CYBB, ALOX5 and GPX2 may be key ferroptosis-related genes in the pathogenesis of Fusarium keratitis.

Continuous voriconazole lavage in managing moderate and severe fungal keratitis: a randomized controlled trial

PURPOSE

To assess the effectiveness and safety of continuous lavage with 1% voriconazole (CL) for moderate and severe fungal keratitis.

METHODS

Thirty-one patients were randomized to receive topical eye drops either alone (T) or combined with continuous 1% voriconazole lavage (CL-T). The primary outcome was the cure rate at 3 months. The secondary outcomes were the 6-day efficacy, 3-day infiltration size and depth, hypopyon height, central corneal thickness (CCT), epithelial defect size, and subject feelings and clinical signs assessment scores.

RESULTS

At 3 months, the cure rate was comparable between the groups in patients with moderate fungal keratitis (66.7% vs. 62.5%, P = 0.60). However, among severe cases, 4 cases (44.4%) in the CL-T group healed successfully, while none in the T group; this difference was not significant (P = 0.08), although it was very close to 0.05. This may be related to the small sample size. After 6 days, the percentage of patients with "worsened" ulcers in the CL-T group was lower than that in the T group (0% vs. 31%, P = 0.043). The infiltration size, infiltration depth, and hypopyon height in the CL-T group were smaller than those in the T group after 3 days (all P < 0.05). There was no difference in CCT, epithelial defect size, subject feelings scores, or clinical signs scores between groups.

CONCLUSION

These outcomes suggest that CL is an effective and safe adjuvant method for controlling the progression of moderate and severe fungal keratitis.

TRIAL REGISTRATION NUMBER

ChiCTR2100050565.

Deep Convolutional Neural Networks Detect no Morphological Differences Between Culture-Positive and Culture-Negative Infectious Keratitis Images

Purpose

To determine whether convolutional neural networks can detect morphological differences between images of microbiologically positive and negative corneal ulcers.

Methods

A cross-sectional comparison of prospectively collected data consisting of bacterial and fungal cultures and smears from eyes with acute infectious keratitis at Aravind Eye Hospital. Two convolutional neural network architectures (DenseNet and MobileNet) were trained using images obtained from handheld cameras collected from culture-positive and negative images and smear-positive and -negative images. Each architecture was trained on two image sets: (1) one with labels assigned using only culture results and (2) one using culture and smear results. The outcome measure was area under the receiver operating characteristic curve for predicting whether an ulcer would be microbiologically positive or negative.

Results

There were 1970 images from 886 patients were included. None of the models were better than random chance at predicting positive microbiologic results (area under the receiver operating characteristic curve ranged from 0.49 to 0.56; all confidence intervals included 0.5).

Conclusions

These two state-of-the-art deep convolutional neural network architectures could not reliably predict whether a corneal ulcer would be microbiologically positive or negative based on clinical photographs. This absence of detectable morphological differences informs the future development of computer vision models trained to predict the causative agent in infectious keratitis using corneal photography.

Translational Relevance

These deep learning models were not able to identify morphological differences between microbiologically positive and negative corneal ulcers. This finding suggests that similar artificial intelligence models trained to identify the causative pathogen using only microbiologically positive cases may have potential to generalize well, including to cases with falsely negative microbiologic testing.

[Experimental study of the effectiveness of terbinafine in the treatment of fungal keratitis]

Methods of treatment of fungal keratitis in the Russian Federation currently consist of non-standardized off-label methods due to the lack of licensed commercial antifungal solutions designed for use in ophthalmology. The article presents the results of successful treatment of fungal keratitis in experimental animals with a terbinafine solution, with effectiveness comparable to voriconazole lyophilizate diluted to 1%.

PURPOSE

The study analyzed the effectiveness of terbinafine solution in the experimental treatment of fungal keratitis.

MATERIAL AND METHODS

The study was conducted on Soviet chinchilla rabbits with signs of keratomycosis modeled during the experiment. Fifteen experimental animals were randomly divided into three comparison groups: group 1 received treatment with 1% voriconazole, group 2 - 0.1% terbinafine, group 3 did not receive treatment.

RESULTS

Groups of rabbits treated with voriconazole and terbinafine showed comparable positive treatment results, but in the terbinafine group epithelization was completed earlier, and complete sanitation of the fungal microflora was achieved on day 3.

CONCLUSION

One important advantage of 0.1% terbinafine suspension lies in availability of a local form designed for ophthalmological application. The advantage of local 0.1% terbinafine suspension is supported by the combination of signs and results, and the obtained data may be used for introducing it into practice after further clinical trials.

A 5-Year Retrospective Analysis of the Risk Factors, Treatment, and Prognosis of Patients With Fungal Keratitis in Heilongjiang, China

PURPOSE

To report the epidemiologic features, laboratory findings, and treatment outcomes of patients with fungal keratitis (FK) during a busy farming period (May, June, and September to November) in Heilongjiang Province, China.

DESIGN

Retrospective, observational case series.

METHODS

In total, 251 patients diagnosed with FK at the Eye Hospital, First Affiliated Hospital of Harbin Medical University, from 2017 to 2021 were identified. Medical records were retrospectively analyzed, and demographic features, risk factors, monthly distributions, clinical characteristics, laboratory findings, treatment strategies, and prognostic data were collected.

RESULTS

The number of FK cases in the busy farming period accounted for 74.1% (186/251) of the total. The mean patient age was 58.2±9.5 years. Males (66.7%) were more likely to develop FK than females (33.3%), and plant-related trauma was the main cause in 80.1% (149/186) of the cases. The most common causative fungal species was Fusarium (34.9%). In vivo confocal microscopy had the highest positivity rate for FK diagnosis (94.6%). The depth of hypopyon, depth of hyphae or spores, and infiltrate width were significantly positively correlated with delayed presentation.

CONCLUSIONS

Patients with a longer time of presentation to the hospital were more likely to undergo surgery because of topical medical therapy failure. The most important measures for FK prevention are the use of eye protection during outdoor work and visiting the hospital for treatment as soon as possible after eye injury.

Management of Filamentous Fungal Keratitis: A Pragmatic Approach

Filamentous fungal infections of the cornea known as filamentous fungal keratitis (FK) are challenging to treat. Topical natamycin 5% is usually first-line treatment following the results of several landmark clinical trials. However, even when treated intensively, infections may progress to corneal perforation. Current topical antifungals are not always effective and are often unavailable. Alternatives topical therapies to natamycin include voriconazole, chlorhexidine, amphotericin B and econazole. Surgical therapy, typically in the form of therapeutic penetrating keratoplasty, may be required for severe cases or following corneal perforation. Alternative treatment strategies such as intrastromal or intracameral injections of antifungals may be used. However, there is often no clear treatment strategy and the evidence to guide therapy is often lacking. This review describes the different treatment options and their evidence and provides a pragmatic approach to the management of fungal keratitis, particularly for clinicians working in tropical, low-resource settings where fungal keratitis is most prevalent.

The Case for Fungal Keratitis to Be Accepted as a Neglected Tropical Disease

Amongst the treatable cause of blindness among young people, fungal keratitis ranks high. There are an estimated 1,051,787 to 1,480,916 eyes affected annually, with 8–11% of patients having to have the eye removed. Diagnosis requires a corneal scraping, direct microscopy and fungal culture with a large number of airborne fungi implicated. Treatment involves the intensive application of antifungal eye drops, preferably natamycin, often combined with surgery. In low-resource settings, inappropriate corticosteroid eye drops, ineffective antibacterial therapy, diagnostic delay or no diagnosis all contribute to poor ocular outcomes with blindness (unilateral or bilateral) common. Modern detailed guidelines on fungal keratitis diagnosis and management are lacking. Here, we argue that fungal keratitis should be included as a neglected tropical disease, which would facilitate greater awareness of the condition, improved diagnostic capability, and access to affordable antifungal eye medicine.

[Fusarium Keratitis-an upcoming threat in Germany?]

BACKGROUND

Fungal keratitis due to Fusarium species is known to be typical of developing countries; however, with the increasing use of contact lenses a rise of Fusarium keratitis has been observed in Germany.

METHODS

In a monocentric retrospective study, we analyzed all patients who presented to our university eye hospital with infectious keratitis between January 2011 and December 2021 and had a proof of Fusarium species in either microscopy, culture or PCR.

RESULTS

We could identify 13 patients with a proof of Fusarium species. A significant increase of cases in 2021 was observed. In 76.9% of our cases the patients were female and in 76.9% the patients had a history of prior contact lens use. In only 4 cases the initial corneal sample gave a positive result for Fusarium. On average the suspicion of fungal keratitis arose 13.1 days after onset of symptoms, correct diagnosis was achieved after 14.6 days. All isolated specimens showed resistance against at least one of the common fungicides. In 70% of our cases treatment with penetrating keratoplasty was necessary. The patients showed a 57.1% recurrence rate after penetrating keratoplasty. In 80% of our cases best documented visual acuity after Fusarium keratitis was ≤ 0.4.

CONCLUSION

Due to difficult detection and a high resistance rate to common antifungals, Fusarium keratitis is prone to delayed diagnosis and limited treatment outcomes. Whenever risk factors are present and infectious keratitis does not respond to antibiotics, antimycotic treatment must be initiated. Early keratoplasty may be necessary.

Fungal Keratitis: Clinical Features, Risk Factors, Treatment, and Outcomes

Fungal keratitis (FK) can be challenging to diagnose and treat. In this retrospective case series, FK cases presenting at the University of Pittsburgh Medical Center, Pennsylvania, USA, from 2015 to 2021 were reviewed for ocular risk factors, clinical presentation, management, and outcomes. Twenty-eight cases of FK were included. The median presenting age was 58.5 (18.5) years, and the median symptom duration prior to presentation was 10 (35.8) days. Predisposing ocular risk factors included contact lens use (67.9%), recent ocular trauma/abrasion (42.9%), and history of ocular surgery (42.9%). The median presenting visual acuity (VA) was 1.35 (1.72) LogMAR. About half presented with a central ulcer (42.9%), large infiltrate (6.7 (6.3) mm2), corneal thinning (50.0%), and hypopyon (32.1%). The majority of isolated fungal species were filamentous (75.0%). Most common antifungal medications included topical voriconazole (71.4%) and natamycin (53.6%) drops and oral voriconazole (64.3%). Surgical management was necessary in 32.1% of cases and enucleation in one case. Defect resolution occurred in 42.5 (47.0) days, and median final VA was 0.5 (1.84) LogMAR. Features associated with poor final visual outcomes included poor initial VA (p < 0.001) and larger defect size (p = 0.002). In conclusion, unlike prior studies in the northeast region of the USA, FK was commonly caused by filamentous fungi, and antifungal management most often consisted of topical and oral voriconazole.

Therapy for contact lens-related ulcers

PURPOSE OF REVIEW

The current review covers the current literature and practice patterns of antimicrobial therapy for contact lens-related microbial keratitis (CLMK). Although the majority of corneal ulcers are bacterial, fungus and acanthamoeba are substantial contributors in CLMK and are harder to treat due to the lack of commercially available topical medications and low efficacy of available topical therapy.

RECENT FINDINGS

Topical antimicrobials remain the mainstay of therapy for corneal ulcers. Fluoroquinolones may be used as monotherapy for small, peripheral bacterial ulcers. Antibiotic resistance is a persistent problem. Fungal ulcers are less responsive to topical medications and adjunct oral or intrastromal antifungal medications may be helpful. Acanthamoeba keratitis continues to remain a therapeutic challenge but newer antifungal and antiparasitic agents may be helpful adjuncts. Other novel and innovative therapies are being studied currently and show promise.

SUMMARY

Contact lens-associated microbial keratitis is a significant health issue that can cause vision loss. Treatment remains a challenge but many promising diagnostics and procedures are in the pipeline and offer hope.

Infectious keratitis: A review

Globally, infectious keratitis is the fifth leading cause of blindness. The main predisposing factors include contact lens wear, ocular injury and ocular surface disease. Staphylococcus species, Pseudomonas aeruginosa, Fusarium species, Candida species and Acanthamoeba species are the most common causal organisms. Culture of corneal scrapes is the preferred initial test to identify the culprit organism. Polymerase chain reaction (PCR) tests and in vivo confocal microscopy can complement the diagnosis. Empiric therapy is typically commenced with fluoroquinolones, or fortified antibiotics for bacterial keratitis; topical natamycin for fungal keratitis; and polyhexamethylene biguanide or chlorhexidine for acanthamoeba keratitis. Herpes simplex keratitis is mainly diagnosed clinically; however, PCR can also be used to confirm the initial diagnosis and in atypical cases. Antivirals and topical corticosteroids are indicated depending on the corneal layer infected. Vision impairment, blindness and even loss of the eye can occur with a delay in diagnosis and inappropriate antimicrobial therapy.

Epidemiology and clinical outcomes of microbial keratitis in South East Nepal: a mixed-methods study

Objective

To describe the epidemiology of microbial keratitis in patients presenting to a tertiary eye hospital in South East Nepal alongside qualitative interviews exploring patient perspectives on barriers to accessing eye care services.

Methods and analysis

All patients with microbial keratitis (>16 years) presenting to Sagarmatha Choudhary Eye Hospital, Nepal between 1 May 2017 and 31 July 2017 were recruited. Data were collected on patient demographics, precipitating factors and pathway to care. Clinical examination was performed and microbiological samples collected. Visual acuity was measured at final follow-up. Semistructured interviews and focus group discussions explored the patient journey and barriers to accessing care.

Results

We recruited 174 participants; 88 (51%) were male (mean age of 47 years) and 126 (72%) were farmers. Ocular trauma with vegetative matter was reported by 79 (45%) and 84 (48%) had fungal infections. Visual acuity was <3/60 in 107 (61%) of affected eyes at presentation, reducing to 73 (42%) at last follow-up. Factors associated with poor visual outcome were trauma with vegetative matter, delayed presentation and poor visual acuity at presentation. Qualitative interviews with 40 patients identified lack of awareness of the disease and available services, poor knowledge and practice of community health workers and lack of affordability and accessibility of treatment as important barriers.

Conclusion

The epidemiology of microbial keratitis in this region was similar to other tropical regions. Patient interviews highlighted need for public health awareness campaigns on microbial keratitis, training of community health staff on the urgency of this condition and improvements in accessibility and affordability of ocular treatments.

Image-Based Differentiation of Bacterial and Fungal Keratitis Using Deep Convolutional Neural Networks

Purpose

Develop computer vision models for image-based differentiation of bacterial and fungal corneal ulcers and compare their performance against human experts.

Design

Cross-sectional comparison of diagnostic performance.

Participants

Patients with acute, culture-proven bacterial or fungal keratitis from 4 centers in South India.

Methods

Five convolutional neural networks (CNNs) were trained using images from handheld cameras collected from patients with culture-proven corneal ulcers in South India recruited as part of clinical trials conducted between 2006 and 2015. Their performance was evaluated on 2 hold-out test sets (1 single center and 1 multicenter) from South India. Twelve local expert cornea specialists performed remote interpretation of the images in the multicenter test set to enable direct comparison against CNN performance.

Main Outcome Measures

Area under the receiver operating characteristic curve (AUC) individually and for each group collectively (i.e., CNN ensemble and human ensemble).

Results

The best-performing CNN architecture was MobileNet, which attained an AUC of 0.86 on the single-center test set (other CNNs range, 0.68-0.84) and 0.83 on the multicenter test set (other CNNs range, 0.75-0.83). Expert human AUCs on the multicenter test set ranged from 0.42 to 0.79. The CNN ensemble achieved a statistically significantly higher AUC (0.84) than the human ensemble (0.76; P < 0.01). CNNs showed relatively higher accuracy for fungal (81%) versus bacterial (75%) ulcers, whereas humans showed relatively higher accuracy for bacterial (88%) versus fungal (56%) ulcers. An ensemble of the best-performing CNN and best-performing human achieved the highest AUC of 0.87, although this was not statistically significantly higher than the best CNN (0.83; P = 0.17) or best human (0.79; P = 0.09).

Conclusions

Computer vision models achieved superhuman performance in identifying the underlying infectious cause of corneal ulcers compared with cornea specialists. The best-performing model, MobileNet, attained an AUC of 0.83 to 0.86 without any additional clinical or historical information. These findings suggest the potential for future implementation of these models to enable earlier directed antimicrobial therapy in the management of infectious keratitis, which may improve visual outcomes. Additional studies are ongoing to incorporate clinical history and expert opinion into predictive models.

An Atypical Etiology of Fungal Keratitis Caused by Roussoella neopustulans

Fungal keratitis is caused by a wide spectrum of fungal genera, including molds and yeasts. We report a 42-year-old patient with mycotic keratitis after a direct trauma by a wood fragment. The fungal isolate was identified as Roussoella neopustulans by molecular methods. The treatment with topic natamycin showed progressive improvement of the visual manifestations, and following three months of therapy, the patient regained sight. We report the first case of keratitis associated with R. neopustulans.

Topical Chlorhexidine 0.2% versus Topical Natamycin 5% for the Treatment of Fungal Keratitis in Nepal: A Randomized Controlled Noninferiority Trial

PURPOSE

To investigate if topical chlorhexidine 0.2%, which is low cost and easy to formulate, is noninferior to topical natamycin 5% for the treatment of filamentous fungal keratitis.

DESIGN

Randomized controlled, single-masked, noninferiority clinical trial.

PARTICIPANTS

Adults attending a tertiary-level ophthalmic hospital in Nepal with filamentous fungal infection confirmed on smear or confocal microscopy.

METHODS

Participants were randomly allocated to receive topical chlorhexidine 0.2% or topical natamycin 5%. Primary analysis (intention-to-treat) was by linear regression, using baseline logarithm of the minimum angle of resolution (logMAR) best spectacle-corrected visual acuity (BSCVA) and treatment arm as prespecified covariates. Mixed fungal-bacterial infections were excluded from the primary analysis but included in secondary analyses and secondary safety-related outcomes. The noninferiority margin was 0.15 logMAR. This trial was registered with ISRCTN, number ISRCTN14332621.

MAIN OUTCOME MEASURES

The primary outcome measure was BSCVA at 3 months. Secondary outcome measures included perforation or therapeutic penetrating keratoplasty by 90 days.

RESULTS

Between June 3, 2019, and November 9, 2020, 354 eligible participants were enrolled and randomly assigned: 178 to chlorhexidine and 176 to natamycin. Primary outcome data were available for 153 and 151 of the chlorhexidine and natamycin groups, respectively. Of these, mixed bacterial-fungal infections were found in 20 cases (12/153 chlorhexidine, 8/151 natamycin) and excluded from the primary analysis. Therefore, 284 patients were assessed for the primary outcome (141 chlorhexidine, 143 natamycin). We did not find evidence to suggest chlorhexidine was noninferior to natamycin and in fact found strong evidence to suggest that natamycin-treated participants had significantly better 3-month BSCVA than chlorhexidine-treated participants, after adjusting for baseline BSCVA (regression coefficient, -0.30; 95% confidence interval [CI], -0.42 to -0.18; P < 0.001). There were more perforations and emergency corneal grafts in the chlorhexidine arm (24/175, 13.7%) than in the natamycin arm (10/173, 5.8%; P = 0.018, mixed infections included), whereas natamycin-treated cases were less likely to perforate or require an emergency corneal graft, after adjusting for baseline ulcer depth (odds ratio, 0.34; 95% CI, 0.15-0.79; P = 0.013).

CONCLUSIONS

Treatment with natamycin is associated with significantly better visual acuity, with fewer adverse events, compared with treatment with chlorhexidine. Natamycin remains the preferred first-line monotherapy treatment for filamentous fungal keratitis.

The Role of Topical Povidone-Iodine in the Management of Infectious Keratitis: A Pilot Study

The aim of this prospective explorative study was to evaluate the safety and the effectiveness of topical polyvinylpyrrolidone-iodine (PVP-I) administered during the time-to-results period for pathogen identification and susceptibility testing in patients with infectious keratitis (IK). A corneal swab (CS) for antimicrobial evaluation was performed at enrollment (T0) and topical 0.66%-PVP-I was administered until the laboratory results were available (T1). Ulcer and infiltrate areas and infiltrate depths were compared between T0 and T1 (i.e., time-to-result period). Patients were then shifted to a specific antimicrobial therapy and followed up until resolution of their infiltrates (Tlast-TL). Twenty-five eyes were enrolled, and none showed clinical worsening leading to protocol withdrawal. At T1, ulcer and infiltrate areas showed significant improvement in Gram-positive IK (n = 13–52%; p = 0.027 and p = 0.019, respectively), remained stable in fungal IK (n = 5–20%; both p = 0.98) and increased in those with Gram-negative bacteria (n = 4–16%; p = 0.58 and p = 0.27). Eyes with negative cultures (n = 3–12%) showed complete resolution at T1 and did not initiate any additional antimicrobial therapy. The administration of 0.66% PVP-I during the time-to-result period seems to be a safe strategy in patients with IK while often sparing broad-spectrum antimicrobial agents. In addition, it showed to be effective in eyes with a Gram-positive bacterial infection.

Patterns of Antifungal Resistance in Adult Patients With Fungal Keratitis in South India: A Post Hoc Analysis of 3 Randomized Clinical Trials

IMPORTANCE

Antifungal resistance has been shown to impact treatment success, but research analyzing antifungal resistance is scarce.

OBJECTIVE

To evaluate changes in antifungal resistance over time.

DESIGN, SETTING, AND PARTICIPANTS

Ad hoc analysis of 3 randomized clinical trials including consecutive patients 18 years and older presenting with smear-positive fungal ulcers to Aravind Eye Hospitals in Madurai, Coimbatore, Pondicherry, and Tirunelveli in South India who participated in 1 of 3 clinical trials: the Mycotic Ulcer Treatment Trials (MUTT) I (2010 to 2011) or II (2010 to 2015) or the Cross-Linking Assisted Infection Reduction (CLAIR) trial (2016 to 2018). This post hoc analysis was designed in March 2021 and data were analyzed in May and November 2021.

INTERVENTIONS

Minimum inhibitory concentration (MIC) of natamycin and voriconazole was determined from corneal cultures obtained using standardized methods outlined in the Clinical and Laboratory Standards Institute.

MAIN OUTCOMES AND MEASURES

The primary outcome of this post hoc analysis was MIC of natamycin and voriconazole.

RESULTS

A total of 890 fungal isolates were obtained from 651 patients (mean [SD] age, 49.6 [13.0]; 191 [43.3%] female) from 2010 to 2018. MICs were available for 522 samples in 446 patients. Fungal isolates overall demonstrated a 1.02-fold increase per year in voriconazole resistance as measured by MICs (95% CI, 1.00-1.04; P = .06). In subgroup analyses, Fusarium species demonstrated a 1.04-fold increase in voriconazole resistance per year (95% CI, 1.00-1.06; P = .01). Fungal isolates showed a 1.06-fold increase in natamycin resistance per year overall (95% CI, 1.03-1.09; P < .001). Fusarium species had a 1.06-fold increase in natamycin resistance (95% CI, 1.05-1.08; P < .001), Aspergillus had a 1.09-fold increase in resistance (95% CI, 1.05-1.15; P < .001), and other filamentous fungi had a 1.07-fold increase in resistance to natamycin per year (95% CI, 1.04-1.10; P < .001).

CONCLUSIONS AND RELEVANCE

This post hoc analysis suggests that susceptibility to both natamycin and voriconazole may be decreasing over the last decade in South India. While a trend of increasing resistance could impact treatment of mycoses in general and infectious fungal keratitis in particular, further study is needed to confirm these findings and determine their generalizability to other regions of the world.

TRIAL REGISTRATION

ClinicalTrials.gov Identifiers: NCT00996736 and NCT02570321.

Impact of Sample Collection Order on the Diagnostic Performance of Metagenomic Deep Sequencing for Infectious Keratitis

PURPOSE

The purpose of this article was to evaluate the impact of sample collection order on the diagnostic yield of metagenomic deep sequencing (MDS) for determining the causative pathogen in infectious keratitis.

METHODS

We performed a cross-sectional diagnostic test evaluation among subjects with infectious keratitis at Aravind Eye Hospital in Madurai, India. All subjects underwent corneal scrapings of the affected eye to obtain potassium hydroxide smear, Gram stain, bacterial culture, and fungal culture, in this order. The order of MDS specimen collection relative to smear and culture samples was randomized and served as the primary predictor. Outcomes included the normalized copy number of pathogenic RNA detected by MDS, the proportion of MDS samples that were diagnostic, and the agreement of MDS results with cultures.

RESULTS

MDS samples from 46 subjects with corneal ulcers were evaluated. MDS was positive in 33 subjects (76%) and had 74% overall agreement with culture results. There was no association between order of MDS sample collection and normalized copy number of genetic material detected (P = 0.62) or the likelihood of MDS positivity (P = 0.46). However, the likelihood of agreement between MDS and cultures decreased when MDS corneal swabs were collected after other diagnostic corneal scrapings (P = 0.05).

CONCLUSIONS

The overall yield of MDS for detecting the cause of infectious keratitis was not affected by sample collection order. However, diagnostic agreement between MDS and cultures decreased when MDS samples were collected after other specimens. Additional investigation is warranted to determine whether this represents increased sensitivity of MDS compared with cultures or higher susceptibility to contaminants.

Corneal Perforation as a Complication of Fungal Interface Infectious Keratitis after Deep Anterior Lamellar Keratoplasty

Deep anterior lamellar keratoplasty (DALK) is a surgical intervention for corneal diseases that do not affect the endothelium. The creation of an interface between the donor graft and recipient bed is a typical feature of DALK. Interface infectious keratitis (IIK) is an uncommon complication that originates at this point of contact. The onset of IIK following lamellar keratoplasty can cause delayed visual loss and subsequent endophthalmitis, with primarily fungal etiology (e.g., Candida spp.) and occasionally bacterial etiology. Infection of the lamellar interface may be attributed to contamination of the donor material or to precipitating factors such as loose sutures, persistent epithelial defects, and prolonged topical steroid use; fungal IIK is frequently resistant to medical treatment. Here, we describe the previously unreported occurrence of corneal perforation as a complication of fungal IIK after DALK. A 26-year-old otherwise healthy woman underwent uneventful DALK for advanced keratoconus in the left eye. She was discharged with instructions to apply topical prednisolone acetate and topical moxifloxacin. Culture of the donor corneoscleral rim showed growth of Candida glabrata, although the patient exhibited no clinical signs of infection. Approximately 3 months later, the patient exhibited mild blurring of vision in her left eye. Therefore, treatment was modified to topical amphotericin B and oral voriconazole. One week later, the patient developed multiple, sheath-like whitish creamy infiltrates, primarily in the lamellar interface; a positive Seidel test result indicated the presence of corneal perforation. As treatment for IIK, excisional penetrating keratoplasty (PK) was performed, followed by topical amphotericin B and topical prednisolone acetate treatment. During 12 months of follow-up after PK, the corneal graft was clear and there was no clinical evidence of recurrent keratitis. Prompt excisional PK prevented the progression of IIK to endophthalmitis in our patient. Early intervention with excisional PK should be considered when a diagnosis of fungal IIK is suspected in a patient with a positive donor rim culture, and in whom the condition does not respond to medical treatment. This early intervention is essential to prevent delayed treatment, which could result in corneal perforation and endophthalmitis, with ultimately poor visual outcomes.

Fungal keratitis: A review of clinical presentations, treatment strategies and outcomes

Infectious keratitis is a significant cause of corneal blindness worldwide. Although less prevalent in the developed world, cases of fungal keratitis account for almost half of all keratitis cases, occurring in the developing countries. These cases are one of the most refractory types of infectious keratitis and present various challenges to the treating physician such as delayed presentation, long waiting time for culture positivity, limited availability effective antifungal drugs, prolonged duration for response to therapy, a highly variable spectrum of anti-fungal drug sensitivity and a high recurrence rate following keratoplasty. The advent of rapid diagnostic tools, molecular methods, in vitro anti-fungal drug sensitivity testing, alternatives to natamycin, targeted drug delivery and most importantly the results of large randomized controlled trials have significantly improved our understanding and approach towards the diagnosis and management of cases with fungal keratitis. Overall, Aspergillus and Fusarium species are the most common causes ones of fungal keratitis. History of antecedent trauma is a significant predisposing factor. Corneal scrapings for microscopic evaluation and culture preparation, is the standard of care for establishing the diagnosis of fungal keratitis. Molecular identification of cultures offers accurate identification of fungal pathogens, especially the rare species. Natamycin is an approved first-line drug. Voriconazole is the best alternative, especially for non-fusarium cases. Management involves administration of drugs usually by a combination of various routes, the treatment regimen being individualized depending upon the response to therapy. Photodynamic therapy is a newer treatment modality, being tried for non-responsive cases, before resorting to a therapeutic graft.

Fusarium Keratitis-Review of Current Treatment Possibilities

In many parts of the world, fungi are the predominant cause of infectious keratitis; among which, Fusarium is the most commonly isolated pathogen. The clinical management of this ophthalmic emergency is challenging. Due to the retardation of the first symptoms from an injury and the inability to differentiate fungal from bacterial infections based on clinical symptoms and difficult microbial diagnostics, proper treatment, in many cases, is postponed. Moreover, therapeutical options of Fusarium keratitis remain limited. This paper summarizes the available treatment modalities of Fusarium keratitis, including antifungals and their routes of administration, antiseptics, and surgical interventions.

Recent Perspectives in the Management of Fungal Keratitis

Mycotic keratitis is common in warm, humid regions with a varying profile of pathogenic fungi according to geographical origin, socioeconomic status, and climatic condition. Clinical diagnosis can be challenging in difficult cases and those refractory to treatment. Fungal hyphae on microscopic examination and culture isolation have been the gold standard in the laboratory diagnosis of fungal keratitis. A culture isolate of the aetiological fungus is essential to perform antifungal susceptibility testing. As the culture isolation of fungi is time-consuming, causing delays in the initiation of treatment, newer investigative modalities such as in vivo confocal microscopy and molecular diagnostic methods have recently gained popularity. Molecular diagnostic techniques now help to obtain a rapid diagnosis of fungal keratitis. Genomic approaches are based on detecting amplicons of ribosomal RNA genes, with internal transcribed spacers being increasingly adopted. Metagenomic deep sequencing allows for rapid and accurate diagnosis without the need to wait for the fungus to grow. This is also helpful in identifying new emerging strains of fungi causing mycotic keratitis. A custom-tear proteomic approach will probably play an important diagnostic role in future in the management of mycotic keratitis. Positive repeat cultures are being suggested as an important gauge indicative of a poor prognosis. Positive repeat fungal cultures help to modify a treatment regimen by increasing its frequency, providing the addition of another topical and oral antifungal agent along with close follow-up for perforation and identifying need for early therapeutic keratoplasty. The role of collagen crosslinking in the treatment of fungal keratitis is not convincingly established. Rapid detection by multiplex PCR and antifungal susceptibility testing of the pathogenic fungi, adopted into a routine management protocol of fungal keratitis, will help to improve treatment outcome. Early therapy is essential in minimizing damage to the corneal tissue, thereby providing a better outcome. The role of conventional therapy with polyenes, systemic and targeted therapy of antifungal agents, newer azoles and echinocandins in fungal keratitis has been widely studied in recent times. Combination therapy can be more efficacious in comparison to monotherapy. Given the diversity of fungal aetiology, the emergence of new corneal pathogenic fungi with varying drug susceptibilities, increasing the drug resistance to antifungal agents in some genera and species, it is perhaps time to adopt recent molecular methods for precise identification and incorporate antifungal susceptibility testing as a routine.