The mycotic ulcer treatment trial: a randomized trial comparing natamycin vs voriconazole

Post-traumatic Fungal Keratitis and Endophthalmitis Caused by Coniochaeta Hoffmannii with Late Recurrence following Therapeutic Full-thickness Penetrating Keratoplasty

BACKGROUND

To report a rare case of fungal keratitis and endophthalmitis due to Coniochaeta hoffmannii.

METHODS

Case report.

RESULTS

A 71-year-old immunocompetent male sustained a corneal laceration, traumatic cataract, and retinal detachment due to penetrating injury from a nail pulled from a wooden deck. The patient's postoperative course was complicated by infectious keratitis. Fungal cultures, DNA sequencing and analysis of the internal transcribed spacer sequence confirmed Coniochaeta hoffmannii. Topical and oral voriconazole treatments were initiated; however, due to impending perforation, a therapeutic corneal transplant was required. One year later, the patient developed a new corneal infiltrate at the graft-host junction: Corneal scrapings were culture positive for Coniochaeta hoffmannii. This was treated with topical and intrastromal voriconazole along with oral itraconazole 200 mg once daily for 8 months.

CONCLUSIONS

Coniochaeta hoffmannii may cause recalcitrant keratitis and endophthalmitis, which required longstanding antifungal treatment.

Thermosensitive Tri-Block Polymer Nanoparticle-Hydrogel Composites as Payloads of Natamycin for Antifungal Therapy Against Fusarium Solani

Purpose

Fusarium Solani is the principal pathogen associated with fungal keratitis. As a sensitive drug to F. Solani, natamycin (NAT) was limited by the poor penetration and low bioavailability in clinical application. The aim of this study was to develop a new type of tri-block polymer nanoparticle-gel complex (Gel@PLGA-PEI-PEG@NAT) for delivering NAT and evaluate its physicochemical properties, antifungal activity, safety, penetrability, adhesion, and efficacy in treating fungal keratitis.

Methods

PLGA-PEI-PEG@NAT was prepared and characterized with a nano-particle size analyzer, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The minimum inhibitory concentration (MIC), cytotoxicity, penetrability of NAT (Natacyn^® 5% ophthalmic suspension; Alcon) and PLGA-PEI-PEG@NAT with different concentrations were assessed. The eye surface retention time, ocular irritation, and curative effect of the NAT ophthalmic suspension and Gel@PLGA-PEI-PEG@NAT on a rabbit fungal keratitis model were evaluated.

Results

PLGA-PEI-PEG@NAT had a particle size of 150 nm, a positive surface charge, and a sustained-release effect. The MIC for F. Solani was 2 μg/mL. A cytotoxicity test and ocular irritation test showed that PLGA-PEI-PEG@NAT and Gel@PLGA-PEI-PEG@NAT had good biocompatibility and no obvious irritation for rabbit corneas. Penetration experiments confirmed that PLGA-PEI-PEG@NAT can successfully enter corneal epithelial cells and through the cornea to enter the anterior chamber. Compared with NAT ophthalmic suspension, Gel@PLGA-PEI-PEG@NAT had stronger cornea permeation at the same concentration. The therapeutic effect and precorneal retention ability of the NAT ophthalmic suspension and Gel@PLGA-PEI-PEG@NAT on the fungal keratitis rabbit model were compared. Gel@PLGA-PEI-PEG@NAT achieved a better therapeutic effect at a lower drug concentration, and its eye surface retention time was significantly longer than that of the NAT ophthalmic suspension.

Conclusion

Gel@PLGA-PEI-PEG@NAT was shown to be a safe and effective nanodrug delivery system for NAT. It has great potential to improve the cure rate of fungal keratitis, reduce the administration frequency during the treatment process, and improve patient compliance.

Clinical profile and treatment outcomes of Fusarium keratitis

Purpose:

To determine the seasonality, clinical profile, and treatment outcome of Fusarium keratitis.

Methods:

A retrospective medical chart review of 97 patients with culture-proven Fusarium keratitis at a tertiary eye care institution from January 2018 to December 2019.

Results:

The median (SD) age at enrollment was 44.6 (16) years; 75 (79.8%) of them were male. Presence of infiltrate less than 4 mm² at baseline indicated 4.4 times the odds of achieving final BCVA more than 20/60 (95% CI: 1.4–13.3; P = 0.008). The absence of surgical management indicated 8.1 times the odds of achieving final BCVA of more than 20/60 (95% CI: 0.9–71.5; P = 0.06). The visual acuity at presentation, duration between symptoms and presentation, history of ocular trauma, previous use of topical medications, and presence of hypopyon were not identified as significant predictors of final BCVA in the multivariable regression analysis.

Conclusion:

Smaller infiltrate size and absence of surgical management are the significant predictors of good visual outcome. Visual outcome of Fusarium keratitis is poor, and a significant number of patients did not respond to anti-fungal therapy and had to undergo surgeries. To the best of our knowledge, this is the largest case series on Fusarium keratitis to date.

Microbial Keratitis in Nepal: Predicting the Microbial Aetiology from Clinical Features

Fungal corneal infection (keratitis) is a common clinical problem in South Asia. However, it is often challenging to distinguish this from other aetiologies, such as bacteria or acanthamoeba. In this prospective study, we investigated clinical and epidemiological features that can predict the microbial aetiology of microbial keratitis in Nepal. We recruited patients presenting with keratitis to a tertiary eye hospital in lowland eastern Nepal between June 2019 and November 2020. A structured assessment, including demographics, history, and clinical signs, was carried out. The aetiology was investigated with in vivo confocal microscopy and corneal scrape for microscopy and culture. A predictor score was developed using odds ratios calculated to predict aetiology from features. A fungal cause was identified in 482/642 (75.1%) of cases, which increased to 532/642 (82.9%) when including mixed infections. Unusually, dematiaceous fungi accounted for half of the culture-positive cases (50.6%). Serrated infiltrate margins, patent nasolacrimal duct, raised corneal slough, and organic trauma were independently associated with fungal keratitis (p < 0.01). These four features were combined in a predictor score. The probability of fungal keratitis was 30.1% if one feature was present, increasing to 96.3% if all four were present. Whilst microbiological diagnosis is the "gold standard" to determine the aetiology of an infection, certain clinical signs can help direct the clinician to find a presumptive infectious cause, allowing appropriate treatment to be started without delay. Additionally, this study identified dematiaceous fungi, specifically Curvularia spp., as the main causative agent for fungal keratitis in this region. This novel finding warrants further research to understand potential implications and any trends over time.

Microbial Profile and Clinical Outcomes of Fungal Keratitis at a Single-Center Tertiary Care Hospital

PURPOSE

To evaluate baseline characteristics, microbiological spectrum, management, and outcomes of patients with culture-proven fungal keratitis.

METHODS

Retrospective review of all patients with culture-proven fungal keratitis seen over 6 years at a tertiary referral center.

RESULTS

The present study included 62 eyes from 62 patients. Infection with filamentous organisms was more common than with yeast (66.1% vs 27.4%). The most common filamentous organisms were Fusarium (17.7%) and Aspergillus (16.1%), while the most common yeast was Candida (24.2%). The main predisposing factor for filamentous keratitis was contact lens use. Yeast keratitis is most associated with an immunocompromised host and ocular surface disease. Corneal perforation (20.0%) and surgical interventions (46.8%) were common, with 27.4% of eyes requiring at least one penetrating keratoplasty. Filamentous keratitis is more likely than yeast keratitis to require urgent penetrating keratoplasty or enucleation and to receive more than one topical and systemic antifungal agent. Visual outcomes were poor with nearly half of the eyes remaining at 20/200 or worse upon resolution of infection. Worse visual outcomes were associated with poor vision at presentation and a history of ocular surface disease. Antifungal susceptibility testing was not routinely performed, but it demonstrated a relatively high minimum inhibitory concentration for at least one antifungal drug in 90% of cases when performed (16.1%) and guided the direction of treatment for 80% of the cases.

CONCLUSION

Fungal keratitis is visually devastating. Infections with filamentous fungi predominated over yeast and were generally treated more aggressively both medically and surgically. Filamentous and yeast keratitis had similar durations of infections and visual outcomes. Antifungal susceptibility testing influenced treatment in 80% of cases in which it was performed.

Differentiation of Active Corneal Infections from Healed Scars Using Deep Learning

PURPOSE

To develop and evaluate an automated, portable algorithm to differentiate active corneal ulcers from healed scars using only external photographs.

DESIGN

A convolutional neural network was trained and tested using photographs of corneal ulcers and scars.

PARTICIPANTS

De-identified photographs of corneal ulcers were obtained from the Steroids for Corneal Ulcers Trial (SCUT), Mycotic Ulcer Treatment Trial (MUTT), and Byers Eye Institute at Stanford University.

METHODS

Photographs of corneal ulcers (n = 1313) and scars (n = 1132) from the SCUT and MUTT were used to train a convolutional neural network (CNN). The CNN was tested on 2 different patient populations from eye clinics in India (n = 200) and the Byers Eye Institute at Stanford University (n = 101). Accuracy was evaluated against gold standard clinical classifications. Feature importances for the trained model were visualized using gradient-weighted class activation mapping.

MAIN OUTCOME MEASURES

Accuracy of the CNN was assessed via F1 score. The area under the receiver operating characteristic (ROC) curve (AUC) was used to measure the precision-recall trade-off.

RESULTS

The CNN correctly classified 115 of 123 active ulcers and 65 of 77 scars in patients with corneal ulcer from India (F1 score, 92.0% [95% confidence interval (CI), 88.2%-95.8%]; sensitivity, 93.5% [95% CI, 89.1%-97.9%]; specificity, 84.42% [95% CI, 79.42%-89.42%]; ROC: AUC, 0.9731). The CNN correctly classified 43 of 55 active ulcers and 42 of 46 scars in patients with corneal ulcers from Northern California (F1 score, 84.3% [95% CI, 77.2%-91.4%]; sensitivity, 78.2% [95% CI, 67.3%-89.1%]; specificity, 91.3% [95% CI, 85.8%-96.8%]; ROC: AUC, 0.9474). The CNN visualizations correlated with clinically relevant features such as corneal infiltrate, hypopyon, and conjunctival injection.

CONCLUSIONS

The CNN classified corneal ulcers and scars with high accuracy and generalized to patient populations outside of its training data. The CNN focused on clinically relevant features when it made a diagnosis. The CNN demonstrated potential as an inexpensive diagnostic approach that may aid triage in communities with limited access to eye care.

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.

Expert Performance in Visual Differentiation of Bacterial and Fungal Keratitis

This study quantifies the performance of an international cohort of cornea specialists in image-based differentiation of bacterial and fungal keratitis, identifying significant regional variation and establishing a reference standard for comparison against machine learning models.

Diagnosing Fungal Keratitis and Simultaneously Identifying Fusarium and Aspergillus Keratitis with a Dot Hybridization Array

Fungal keratitis (FK) is one of the most common microbial keratitis, which often leads to poor prognosis as a result of delayed diagnosis. Several studies implied that early differentiation of the two major FK, Fusarium and Aspergillus keratitis, could be helpful in selecting effective anti-fungal regimens. Therefore, a novel dot hybridization array (DHA) was developed to diagnose FK and differentiate Fusarium and Aspergillus keratitis in this study. One hundred forty-six corneal scrapes obtained from one hundred forty-six subjects impressed with clinically suspected FK were used to evaluate the performance of the DHA. Among these patients, 107 (73.3%) patients had actual FK confirmed by culture and DNA sequencing. We found that the DHA had 93.5% sensitivity and 97.4% specificity in diagnosing FK. In addition, this array had 93.2% sensitivity and 93.8% specificity in diagnosing Fusarium keratitis, as well as 83.3% sensitivity and 100% specificity in diagnosing Aspergillus keratitis. Furthermore, it had 83.9% sensitivity and 100% specificity in identifying Fusarium solani keratitis. Thus, this newly developed DHA will be beneficial to earlier diagnosis, more precise treatment, and improve prognosis of FK, by minimizing medical refractory events and surgical needs.

Expression of immune response genes in human corneal epithelial cells interacting with Aspergillus flavus conidia

Background

Aspergillus flavus, one of the causative agents of human fungal keratitis, can be phagocytosed by human corneal epithelial (HCE) cells and the conidia containing phagosomes mature into phagolysosomes. But the immunological responses of human corneal epithelial cells interacting with A. flavus are not clear. In this study, we report the expression of immune response related genes of HCE cells exposed to A. flavus spores using targeted transcriptomics.

Methods

Human corneal epithelial cell line and primary cultures were grown in a six-well plate and used for coculture experiments. Internalization of the conidia was confirmed by immunofluorescence microscopy of the colocalized endosomal markers CD71 and LAMP1. Total RNA was isolated, and the quantity and quality of the isolated RNA were assessed using Qubit and Bioanalyzer. NanoString nCounter platform was used for the analysis of mRNA abundance using the Human Immunology panel. R-package and nSolver software were used for data analysis. KEGG and FunRich 3.1.3 tools were used to analyze the differentially expressed genes.

Results

Different morphotypes of conidia were observed after 6 h of coculture with human corneal epithelial cells and found to be internalized by epithelial cells. NanoString profiling showed more than 20 differentially expressed genes in immortalized human corneal epithelial cell line and more than ten differentially expressed genes in primary corneal epithelial cells. Distinct set of genes were altered in their expression in cell line and primary corneal epithelial cells. KEGG pathway analysis revealed that genes associated with TNF signaling, NF-KB signaling, and Th17 signaling were up-regulated, and genes associated with chemokine signaling and B cell receptor signaling were down regulated. FunRich pathway analysis showed that pathways such as CDC42 signaling, PI3K signaling, and Arf6 trafficking events were activated by the clinical isolates CI1123 and CI1698 in both type of cells.

Conclusions

Combining the transcript analysis data from cell lines and primary cultures, we showed the up regulation of immune defense genes in A. flavus infected cells. At the same time, chemokine signaling and B cell signaling pathways are downregulated. The variability in the expression levels in the immortalized cell line and the primary cultures is likely due to the variable epigenetic reprogramming in the immortalized cells and primary cultures in the absence of any changes in the genome. It highlights the importance of using both cell types in host-pathogen interaction studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-08218-5.

Delay in accessing definitive care for patients with microbial keratitis in Nepal

Background

The aim of this study was to describe the health-seeking journey for patients with microbial keratitis (MK) in Nepal and identify factors associated with delay.

Methods

Prospective cohort study where MK patients attending a large, tertiary-referral eye hospital in south-eastern Nepal between June 2019 and November 2020 were recruited. We collected demographic details, clinical history, and examination findings. Care-seeking journey details were captured including places attended, number of journeys, time from symptom onset, and costs. We compared "direct" with "indirect" presenters, analyzing for predictors of delay.

Results

We enrolled 643 patients with MK. The majority (96%) self-referred. "Direct" attenders accounted for only 23.6% (152/643) of patients, the majority of "indirect" patients initially presented to a pharmacy (255/491). Over half (328/643) of all cases presented after at least 7 days. The total cost of care increased with increasing numbers of facilities visited (p < 0.001). Those living furthest away were least likely to present directly (p < 0.001). Factors independently associated with delayed presentation included distance >50 km from the eye hospital [aOR 5.760 (95% CI 1.829-18.14, p = 0.003)], previous antifungal use [aOR 4.706 (95% CI 3.139-5.360)], and two or more previous journeys [aOR 1.442 (95% CI 1.111-3.255)].

Conclusions

Most patients visited at least one facility prior to our institution, with time to presentation and costs increasing with the number of prior journeys. Distance to the eye hospital is a significant barrier to prompt, direct presentation. Based on these findings, improving access to eye care services, strengthening referral networks and encouraging early appropriate treatment are recommended to reduce delay, ultimately improving clinical outcomes.

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.

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.

Fungal keratitis due to Scopulariopsis brevicaulis and a potential promising therapeutic effect of antibacterial agents: A case report

INTRODUCTION

Microbial keratitis is a serious potentially blinding corneal infection. Contact lens wear remains the most common predisposing factor. Fungal keratitis represent only a small fraction of the overall number of cases of contact lens-associated microbial keratitis, however they are proportionally more severe.

PATIENT CONCERNS

An 18-year-old female, who occasionally used eye cosmetic soft contact lenses, presented with pain, redness, and blurring of vision in her left eye.

DIAGNOSIS

The left eye showed decreased visual acuity, central corneal ulcer and abscess, and severe ciliary injection. A provisional diagnosis of infectious keratitis was considered.

INTERVENTION

Corneal scrapings were aseptically collected and directly inoculated onto sterile bacterial and fungal agar plates that were immediately incubated. The patient was admitted and started on topical and systemic antibacterial agents.

OUTCOMES

The infection showed signs of satisfactory clinical resolution. However, the mold Scopulariopsis brevicaulis was isolated in pure colonies 5 days after presentation.

CONCLUSION

We report the first case from Jordan of fungal keratitis caused by the mold S brevicaulis. A high index of suspicion is required for fungal keratitis caused by S brevicaulis in immunocompetent patients who wear contact lenses despite its rarity. This fungal infection was successfully treated using antibacterial agents. However, larger studies are recommended to investigate the clinical effectiveness of antimicrobial agents that have both antibacterial and antifungal effects and to assess their role as empirical therapeutic modalities for infectious keratitis.

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.

Endothelial Biopsy for the Diagnosis and Management of Culture-Negative Retrocorneal Fungal Keratitis With the Assistance of Optical Coherence Tomography Imaging

PURPOSE

To report a case of a culture-negative deep fungal corneal infection that was diagnosed after histopathology of an anterior segment optical coherence tomography-guided endothelial biopsy.

METHODS

A 22-year-old woman with history of contact lens wear and concomitant topical steroid use presented with a mid-stromal corneal infiltrate that failed to respond to oral acyclovir and topical fortified antibiotics. Although cornea stains, cultures, and confocal microscopy showed negative results, there was high clinical suspicion for fungal keratitis. After 2 months on topical natamycin, oral voriconazole, and serial intrastromal and intracameral voriconazole injections, the infiltrate enlarged and deepened. Imaging with anterior segment optical coherence tomography revealed that the infection had progressed to an endothelial plaque.

RESULTS

Diagnostic endothelial biopsy was performed in the operating room. Cultures showed again negative results, whereas histopathology of the removed specimen revealed fungal elements. The postoperative edema at the site of the biopsy resolved over the course of 4 weeks, and a posterior stromal scar formed. Serial intrastromal and intracameral voriconazole injections were continued for the first postoperative month. At the 1-year and the 3-year follow-up examinations, the patient's vision was 20/20 without recurrence.

CONCLUSIONS

Intraoperative scraping of the endothelial plaque and histopathologic evaluation of the specimen proved to be of utmost importance for definitive diagnosis and resolution of the culture-negative deep fungal infection in this case. This young patient's cornea was retained and vision remains excellent.

Fungal keratitis: Mechanisms of infection and management strategies

Fungal corneal ulcers are an uncommon, yet challenging, cause of vision loss. In the United States, geographic location appears to dictate not only the incidence of fungal ulcers, but also the fungal genera most encountered. These patterns of infection can be linked to environmental factors and individual characteristics of fungal organisms. Successful management of fungal ulcers is dependent on an early diagnosis. New diagnostic modalities like confocal microscopy and polymerase chain reaction are being increasingly used to detect and identify infectious organisms. Several novel therapies, including crosslinking and light therapy, are currently being tested as alternatives to conventional antifungal medications. We explore the biology of Candida, Fusarium, and Aspergillus, the three most common genera of fungi causing corneal ulcers in the United States and discuss current treatment regimens for the management of fungal keratitis.

Clinical and Mycological Features in Fungal Keratitis: Retrospective Single Center Study (2012-2018)

Objectives:

To present the demographic, etiological, clinical, and mycological characteristics and treatment results of fungal keratitis patients admitted to our clinic.

Materials and Methods:

The medical records of patients diagnosed with fungal keratitis between October 2012 and 2018 were reviewed. The diagnosis of fungal keratitis was confirmed mycologically and/or cytologically. Treatment response was defined as complete infiltrate resolution and re-epithelization with medical treatment and minor surgical interventions. Patients who underwent penetrating keratoplasty or evisceration due to clinical deterioration despite treatment were classified as treatment nonresponders and were compared with responders in terms of demographic, etiological, and clinical characteristics.

Results:

Seventy-two (12.8%) of 559 patients diagnosed with microbial keratitis in the 6-year period were fungal keratitis. Of these, 38 cases (38 eyes) without polymicrobial etiology were included in the study. The patients’ mean age was 44.9±19.0 years (range: 2-80) and males predominated (14 females [36.8%], 24 males [63.2%]). Trauma (63.6%) was the most common predisposing factor in patients younger than 40 years old, whereas pathologies impairing ocular surface immunity were the leading risk factor (48.1%) in patients older than 40 years. Filamentous fungi were detected in 34 (89.5%) cases, while yeasts were found in 4 (10.5%) cases. Among 26 cases with positive cultures, Aspergillus species were the most common pathogens (42.3%). Infiltrate size before treatment was larger in nonresponders (14/38, 36.8%) compared to treatment responders (19/38, 50%) (p=0.049). In addition, rates of treatment response were higher in cases in which the infiltrate was located paracentrally compared to other cases (p=0.036).

Conclusion:

Fungal keratitis is an important public health problem in our region. Ocular trauma is a leading etiology in men under the age of 40 years. In the 6-year period, we observed that the main causes of fungal keratitis were filamentous fungi, and most commonly Aspergillus species. In cases presenting with large and central lesions, aggressive treatment options should be considered and these patients should be followed up more closely.

Polymicrobial Keratitis: Risk Factors, Clinical Characteristics, Bacterial Profile, and Antimicrobial Resistance

OBJECTIVE

To describe clinical characteristics, complications, and the most prevalent microorganisms causing polymicrobial keratitis and their antibiotic sensitivities.

METHODS

A cross-sectional study including a consecutive analysis of patient's records with a diagnosis of bacterial keratitis with a positive culture and antibiogram report were included. Patients were grouped into those having monomicrobial and polymicrobial infection. Features studied included demographic and clinical characteristics, risk factors, Gram stain, cultures, and antibiotic sensitivity.

RESULTS

We included 656 patients; in 31.5% more than one microorganism was found. Seven hundred and twenty-three gram-positive bacteria were isolated, and 336 (46.5%) had polymicrobial keratitis. One hundred sixty-one gram-negative bacteria were isolated, and 99 (61.5%) from polymicrobial keratitis. Fourteen (0.60%) patients presented ring infiltrate, and 10 (71.42%) of those patients had polymicrobial keratitis (X2 10.654, P=0.001). Multivariate analysis showed that patients with history of contact lens use (odds ratio [OR] of 1.78, P=0.042), coexistent autoimmune disease (OR 4.64, P=0.03), irregular edges of the infiltrate (OR 2.06, P=0.005), and ring infiltrate (OR 6.034, P=0.005) have a higher risk for developing polymicrobial infection. In the polymicrobial group, gram-positive and gram-negative organisms showed a high sensitivity to Netilmicin.

CONCLUSIONS

We found a high incidence of polymicrobial keratitis. Our results suggest that it should be suspected in patients with a history of contact lens use, coexistent autoimmune disease, infiltrates with indistinct edges, and ring infiltrates. Sensitivities to moxifloxacin are lower than those reported in previous studies, but sensitivity to Netilmicin is higher.

Efficacy of Voriconazole Corneal Intrastromal Injection for the Treatment of Fungal Keratitis

Purpose

To evaluate efficacy and safety of novel tricyclic corneal stroma injection (TCSI) voriconazole for the treatment of fungal keratitis.

Methods

This retrospective cohort study included data of 57 patients (57 eyes) with fungal keratitis. The TCSI group consisted of 27 patients (27 eyes) who were injected voriconazole once via TCSI procedure within one week after enrollment, in addition to conventional antifungal treatment. The control group consisted of 30 patients (30 eyes) who were treated using conventional antifungal treatment modalities. The outcome measures consist of the 3-week and 3-month best-corrected visual acuity (BCVA) values and size of infiltrate or scar, time to re-epithelialization, corneal perforation rate and/or therapeutic penetrating keratoplasty (TPK) requirement, the preoperative and post-TCSI corneal endothelial cell density (ECD), and the intraocular pressure (IOP) of the treated eye and the respective contralateral eye.

Results

There were no significant differences in the baseline demographic and clinical characteristics between the two groups. 3 weeks and 3 months after enrollment, the TCSI group exhibited an increase in visual acuity (P < 0.05), and there was no significant difference in the size of infiltrate or scar between two groups (P > 0.05). Time to re-epithelialization was shorter in the TCSI group than in the control group (P < 0.05). There was no statistically significant difference between corneal ECD on the day before and 7 days after TCSI and the IOP of treated and contralateral healthy eyes on the day before and 1 day, 3 days, 7 days, and 1 month after TCSI (P > 0.05). The difference in the risk of perforation and/or TPK requirement was not statistically significant between two groups (P > 0.05).

Conclusion

Localized injection of voriconazole using TCSI may be a minimally invasive, safe, and effective adjuvant treatment modality for fungal keratitis.

Chlorhexidine gluconate 0.2% as a treatment for recalcitrant fungal keratitis in Uganda: a pilot study

OBJECTIVE

Fungal keratitis is a major ophthalmic public health problem, particularly in low-income and middle-income countries. The options for treating fungal keratitis are limited. Our study aimed to describe the outcomes of using chlorhexidine 0.2% eye-drops as additional treatment in the management of patients with recalcitrant fungal keratitis.

METHODS

This study was nested within a large cohort study of people presenting with microbial keratitis in Uganda. We enrolled patients with recalcitrant fungal keratitis not improving with topical natamycin 5% and commenced chlorhexidine 0.2%. Follow-up was scheduled for 3 months and 1 year. The main outcome measures were healing, visual acuity and scar size at final follow-up.

RESULTS

Thirteen patients were followed in this substudy. The patients were aged 27-73 years (median 43 years). Filamentous fungi were identified by microscopy of corneal scrape samples in all cases. Isolated organisms included Aspergillus spp, Fusarium spp, Candida spp, Bipolaris spp and Acremoninum spp. At the final follow-up, nine patients (75%) had healed; three had vision of better than 6/18. Three patients lost their eyes due to infection. In the remaining nine cases, corneal scarring was variable ranging from 4.6 to 9.4 mm (median 6.6 mm, IQR 5.9-8.0 mm); of these five had dense scars, three had moderate scars and one had a mild scar. None of the patients demonstrated signs of chlorhexidine toxicity during the follow-up.

CONCLUSION

Chlorhexidine 0.2% was found to be a useful sequential adjunctive topical antifungal in cases of fungal keratitis not responding to natamycin 5%, which warrants further evaluation.

Postrefractive infectious keratitis: prevention, diagnosis, management, and prognosis

PURPOSE OF REVIEW

Improve outcomes from an elective procedure by preventing a rare but sight-threatening complication.

RECENT FINDINGS

Advancement in anti-infective prophylaxis, and therefore shift in the causative organism permits better diagnostic and empiric management.

SUMMARY

Infectious keratitis presents in different patterns depending on the refractive procedure. Atypical causative organisms may respond poorly to empiric therapy and impair vision. Therefore, microbial identification is of utmost importance and therapy is adjusted accordingly.

Practical Guidance for Clinical Microbiology Laboratories: Diagnosis of Ocular Infections

The variety and complexity of ocular infections have increased significantly in the last decade since the publication of Cumitech 13B, Laboratory Diagnosis of Ocular Infections (L. D. Gray, P. H. Gilligan, and W. C. Fowler, Cumitech 13B, Laboratory Diagnosis of Ocular Infections, 2010). The purpose of this practical guidance document is to review, for individuals working in clinical microbiology laboratories, current tools used in the laboratory diagnosis of ocular infections. This document begins by describing the complex, delicate anatomy of the eye, which often leads to limitations in specimen quantity, requiring a close working bond between laboratorians and ophthalmologists to ensure high-quality diagnostic care. Descriptions are provided of common ocular infections in developed nations and neglected ocular infections seen in developing nations. Subsequently, preanalytic, analytic, and postanalytic aspects of laboratory diagnosis and antimicrobial susceptibility testing are explored in depth.

Aspergillosis: Epidemiology, Diagnosis, and Treatment

The spectrum of disease produced by Aspergillus species ranges from allergic syndromes to chronic pulmonary conditions and invasive infections. Invasive aspergillosis is a major cause of morbidity and mortality in immunocompromised patients. Risk factors continue to evolve and include newer biological agents that target the immune system and postinfluenza infection; and it has been observed following COVID-19 infection. Diagnosis remains a challenge but non-culture-based methods are available. Antifungal resistance has emerged. Voriconazole remains the treatment of choice but isavuconazole and posaconazole have similar efficacy with less toxicity. Combination therapy is used with extensive infection and in severe immunosuppression.

Drug reservoir function of voriconazole impregnated human amniotic membrane: An in vitro study

Purpose:

Earlier our group has demonstrated the drug reservoir function of the human amniotic membrane (HAM) using stable moxifloxacin and fortified cefazolin ophthalmic formulations and found it as a suitable tool to deliver drugs for an extended duration. The purpose of this study was to evaluate the extended-release kinetics of voriconazole from the impregnated human amniotic membrane (HAM) in vitro.

Methods:

HAM buttons were incubated with freshly prepared 1% topical ophthalmic formulation of voriconazole for 5 different exposure time to investigate the ideal exposure time for the extended-release of voriconazole from HAM. The drug release kinetics was studied in simulated tear fluid for 5 weeks and the amount of voriconazole released at different intervals was estimated using high-performance liquid chromatography (HPLC) with photodiode array (PDA) detector.

Results:

There was a marginal increase in drug entrapment efficiency with increased drug exposure time but neither the drug entrapment nor the drug release was found to be statistically significant (P ≥ 0.5). Voriconazole was detectable even at 5 weeks.

Conclusion:

A sustained release of voriconazole was achieved up to 5 weeks, when voriconazole was incubated with amniotic membrane for all the studied drug soaking times. Thus, voriconazole impregnated amniotic membrane can be considered for the sustained delivery for its in fungal keratitis.

Beauveria bassiana keratitis: Management of an atypical clinical presentation

We report an atypical presentation of Beauveria bassiana keratitis which unusually presented in a 85-year-old patient with a corneal ulcer with an anterior segment inflammation and hypopyon. Despite negative culture and unspecific results from panfungal PCR-based sequencing, the patient was treated for a presumed fungal infection. Following clinical deterioration an emergency surgical intervention with apposition of a corneal patch was performed. Infection resolution was achieved following the introduction of systemic voriconazole to the topical one.

Voriconazole in the successful management of a case of Acanthamoeba-Cladosporium keratitis

Purpose

Acanthamoeba and fungal infections can be recalcitrant to therapy - more so when the deeper layers of the corneas are involved. We describe the diagnosis and successful management strategies employed in a case of deep keratitis due to co-infection with Acanthamoeba and Cladosporium sp.

Observations

Once the diagnosis of co-infection with both Acanthamoeba and Cladosporium was made, treatment was initiated with a combination of PHMB, chlorhexidine, natamycin, and voriconazole; to which the response was favorable. Signs of relapse with spread of the infection to the deeper plane and the presence of endothelial exudates were noted at 5 weeks. This was attributed to poor compliance. Though the response to re-initiation of therapy under direct supervision was once again favorable; it was only after the introduction of intrastromal voriconazole repeated at timely intervals that rapid and complete resolution was obtained.

Conclusions

Severe keratitis due to fungi or Acanthamoeba very often requires surgical intervention. Complete resolution with medical therapy was obtained only after the introduction of intrastromal voriconazole; thereby avoiding a therapeutic keratoplasty. The addition of voriconzole both topically and particularly intrastromally facilitated faster resolution as well as restricted the duration of therapy with more toxic drugs such as phmb and chlorhexidine.

Antimicrobial nanomedicine for ocular bacterial and fungal infection

Ocular infection induced by bacteria and fungi is a major cause of visual impairment and blindness. Topical administration of antibiotics remains the first-line treatment, as effective eradication of pathogens is the core of the anti-infection strategy. Whereas, eye drops lack efficiency and have relatively low bioavailability. Intraocular injection may cause concurrent ocular damage and secondary infection. In addition, antibiotic-based management can be limited by the low sensitivity to multidrug-resistant bacteria. Nanomedicine is proposed as a prospective, effective, and noninvasive platform to mediate ocular delivery and combat pathogen or even resistant strains. Nanomedicine can not only carry antimicrobial agents to fight against pathogens but also directly active microbicidal capability, killing pathogens. More importantly, by modification, nanomedicine can achieve enhanced residence time and release time on the cornea, and easy penetration through corneal tissues into anterior and posterior segments of the eye, thus improving the therapeutic effect for ocular infection. In this review, several categories of antimicrobial nanomedicine are systematically discussed, where the efficiency and possibility of further embellishment and improvement to adapt to clinical use are also investigated. All in all, novel antimicrobial nanomedicine provides potent and prospective ways to manage severe and refractory ocular infections.

Mycotic Keratitis-A Global Threat from the Filamentous Fungi

Mycotic or fungal keratitis (FK) is a sight-threatening disease, caused by infection of the cornea by filamentous fungi or yeasts. In tropical, low and middle-income countries, it accounts for the majority of cases of microbial keratitis (MK). Filamentous fungi, in particular Fusarium spp., the aspergilli and dematiaceous fungi, are responsible for the greatest burden of disease. The predominant risk factor for filamentous fungal keratitis is trauma, typically with organic, plant-based material. In developed countries, contact lens wear and related products are frequently implicated as risk factors, and have been linked to global outbreaks of Fusarium keratitis in the recent past. In 2020, the incidence of FK was estimated to be over 1 million cases per year, and there is significant geographical variation; accounting for less than 1% of cases of MK in some European countries to over 80% in parts of south and south-east Asia. The proportion of MK cases is inversely correlated to distance from the equator and there is emerging evidence that the incidence of FK may be increasing. Diagnosing FK is challenging; accurate diagnosis relies on reliable microscopy and culture, aided by adjunctive tools such as in vivo confocal microscopy or PCR. Unfortunately, these facilities are infrequently available in areas most in need. Current topical antifungals are not very effective; infections can progress despite prompt treatment. Antifungal drops are often unavailable. When available, natamycin is usually first-line treatment. However, infections may progress to perforation in ~25% of cases. Future work needs to be directed at addressing these challenges and unmet needs. This review discusses the epidemiology, clinical features, diagnosis, management and aetiology of FK.

Topical Corticosteroids and Fungal Keratitis: A Review of the Literature and Case Series

The management of fungal keratitis is complex since signs and symptoms are subtle and ocular inflammation is minimal in the preliminary stages of infection. Initial misdiagnosis of the condition and consequent management of inflammation with corticosteroids is a frequent occurrence. Topical steroid use is considered to be a principal factor for development of fungal keratitis. In this review, we assess the studies that have reported outcomes of fungal keratitis in patients receiving steroids prior to diagnosis. We also assess the possible rebound effect present when steroids are abruptly discontinued and the clinical characteristics of three patients in this particular clinical scenario. Previous reports and the three clinical descriptions presented suggest that in fungal keratitis, discontinuing topical steroids can induce worsening of clinical signs. In these cases, we recommend to slowly taper steroids and continue or commence appropriate antifungal therapy.

Current understanding and therapeutic management of contact lens associated sterile corneal infiltrates and microbial keratitis

Contact lenses are widely prescribed in clinical practice with multiple applications and advantages. However, contact lenses can be associated with various complications which range from innocuous to severe. Clinicians thus not only need to possess the ability to prescribe the most appropriate contact lenses for each individual patient but also be able to recognise and manage any associated complications. This review examines the existing literature on the management of corneal infiltrative events associated with soft contact lenses, including microbial keratitis, particularly in the context of practising in Australia. The definitions and diagnosis of corneal infiltrative events, as well as the current understanding of their aetiologies, will be explored. The various aspects of a successful management will be discussed, including the applications of therapeutic agents such as antimicrobial and anti-inflammatory agents, the role of microbiological investigations, and strategies to improve long-term prognosis. The currently available evidence supporting management options will be presented, highlighting the relative abundance of high-level evidence on management protocols, antimicrobial selection and treatment duration for microbial keratitis; and the relative paucity of studies and trials for sterile corneal infiltrative events, despite this condition being much more commonly encountered in clinical practice.

American Academy of Optometry Microbial Keratitis Think Tank

SIGNIFICANCE

Think Tank 2019 affirmed that the rate of infection associated with contact lenses has not changed in several decades. Also, there is a trend toward more serious infections associated with Acanthamoeba and fungi. The growing use of contact lenses in children demands our attention with surveillance and case-control studies.

PURPOSE

The American Academy of Optometry (AAO) gathered researchers and key opinion leaders from around the world to discuss contact lens-associated microbial keratitis at the 2019 AAO Annual Meeting.

METHODS

Experts presented within four sessions. Session 1 covered the epidemiology of microbial keratitis, pathogenesis of Pseudomonas aeruginosa, and the role of lens care systems and storage cases in corneal disease. Session 2 covered nonbacterial forms of keratitis in contact lens wearers. Session 3 covered future needs, challenges, and research questions in relation to microbial keratitis in youth and myopia control, microbiome, antimicrobial surfaces, and genetic susceptibility. Session 4 covered compliance and communication imperatives.

RESULTS

The absolute rate of microbial keratitis has remained very consistent for three decades despite new technologies, and extended wear significantly increases the risk. Improved oxygen delivery afforded by silicone hydrogel lenses has not impacted the rates, and although the introduction of daily disposable lenses has minimized the risk of severe disease, there is no consistent evidence that they have altered the overall rate of microbial keratitis. Overnight orthokeratology lenses may increase the risk of microbial keratitis, especially secondary to Acanthamoeba, in children. Compliance remains a concern and a significant risk factor for disease. New insights into host microbiome and genetic susceptibility may uncover new theories. More studies such as case-control designs suited for rare diseases and registries are needed.

CONCLUSIONS

The first annual AAO Think Tank acknowledged that the risk of microbial keratitis has not decreased over decades, despite innovation. Important questions and research directions remain.

Identification and molecular characterization of Subramaniula asteroides causing human fungal keratitis: a case report

Background

Keratitis due to by filamentous fungi are not easy to diagnose thus causing a delay in correct therapy. There are many descriptions of keratitis due to Candida, Fusarium and Aspergillus genera. Subramaniula genus has only recently been reported to cause human infections and there are few descriptions of eye infections due to this filamentous fungus. Diagnosis of fungal keratitis is usually based on microscopic and cultural techniques of samples obtained by corneal swabbing or scraping. Considering the amount of time required to obtain culture results it is wise to use other diagnostic methods, such as molecular analyses. Therapeutic options against these fungi are limited by low tissue penetration in the eye due to ocular barriers. We describe the first case of S. asteroides human keratitis treated with isavuconazole.

Case presentation

We describe a rare case of fungal keratitis unresponsive to antimicrobial treatment in a 65-year-old male patient without a history of diabetes or immunological diseases. He reported that the onset of symptoms occurred during a long holiday in Cape Verde Island. Initial treatment with topical antibiotics associated to steroids were ineffective, allowing a slow clinical progression of disease to corneal perforation. On admission in our Hospital, slit-lamp examination of the left eye showed conjunctival congestion and hyperemia, a large inferior corneal ulceration with brown pigment, corneal edema, about 3 mm of hypopyon and irido-lenticular synechiae. The slow clinical progression of the disease to corneal perforation and the aspect of the ulcer were consistent with a mycotic etiology. Molecular methods used on fungal colonies isolated by Sabouraud’s dextrose agar cultures allowed the identification of Subramaniula asteroids from corneal scraping. Antimicrobial test showed a good susceptibility of this filamentous fungus to voriconazole and isavuconazole. Moreover, this fungal keratitis was successfully treated with isavuconazole, without side effects, observing a progressive clinical improvement.

Conclusions

Molecular methods may be useful for the identification of filamentous fungal keratitis on scraping samples thus shortening the time of diagnosis. Systemic therapy by isavuconazole could be useful to treat the filamentous fungal keratitis, reducing the possible adverse effects due to the use of voriconazole by systemic administration.

The role of fungi in fungal keratitis

Fungal keratitis (FK) accounts for approximately half of the microbial keratitis encountered in low middle income countries (LMICs) and predominantly affect the working rural-poor. FK causes significant morbidity with the majority of patients left with moderate or worse visual impairment and approximately 25% requiring expensive and often unsuccessful surgical interventions. The severity of FK and the resultant corneal damage or resolution can be attributed to i) the virulence and bioburden of the fungal pathogen, ii) the host defense mechanism and immune response and iii) sub-optimal diagnostics and anti-fungal treatment strategies. This review provides a comprehensive overview of the multifaceted components that drive FK progression and resolution, highlighting where knowledge gaps exist and areas that warrant further research.

Association of Postfungal Keratitis Corneal Scar Features With Visual Acuity

Importance

Corneal opacity is a leading cause of visual impairment worldwide; however, the specific features of corneal scars, which decrease visual acuity, have not been well characterized.

Objective

To investigate which features of a postfungal keratitis corneal scar contribute to decreased visual acuity after an episode of infectious keratitis and evaluate whether any corneal features may be used as outcomes for clinical trials.

Design, Setting, and Participants

In this ancillary, prospective cross-sectional study, a subset of study participants treated for fungal keratitis (n = 71) as part of the Mycotic Ulcer Treatment Trial I (MUTT I) underwent best spectacle-corrected visual acuity (BSCVA) and best contact lens-corrected visual acuity examination, Scheimpflug imaging, and anterior segment optical coherence tomography at a referral hospital in India approximately 2 years after enrollment. Data were collected from December 3, 2012, to December 19, 2012, and analyses were performed from December 2, 2013, to October 2, 2019.

Main Outcomes and Measures

Linear regression models were used to evaluate the importance of various corneal features for BSCVA and to assess whether these features could be used to differentiate the 2 treatment arms of the MUTT I trial.

Results

Seventy-one patients (42 men [59.1%]; median age, 48 [range, 39-60] years) were examined at a median (IQR) time of 1.8 (1.4-2.2) years after enrollment. The mean (SD) logMAR BSCVA was 0.17 (0.19) (Snellen equivalent, 20/32). In multivariable linear regression models, BSCVA was most associated with irregular astigmatism (1.0 line of worse BSCVA per 1-line difference between BSCVA and contact lens visual acuity; 95% CI, 0.6-1.4) and corneal scar density (1.5 lines of worse vision per 10-unit increase in the mean central corneal density; 95% CI, 0.8-2.3). The thinnest point of the cornea was the metric that best discriminated between the natamycin- and voriconazole-treated ulcers in MUTT I, with 29.3 μm (95% CI, 7.1-51.6 μm) less thinning in natamycin-treated eyes.

Conclusions and Relevance

Both irregular astigmatism and corneal scar density may be important risk factors for BSCVA in a population with relatively mild, healed fungal corneal ulcers. The thinnest point of the corneal scar may be a cornea-specific outcome that could be used to evaluate treatments for corneal ulcers.

Cross-Linking Assisted Infection Reduction (CLAIR): A Randomized Clinical Trial Evaluating the Effect of Adjuvant Cross-Linking on Bacterial Keratitis

PURPOSE

To determine whether there is a benefit to adjuvant corneal cross-linking (CXL) for bacterial keratitis.

METHODS

This is an outcome-masked, randomized controlled clinical trial. Consecutive patients presenting with a smear-positive bacterial ulcer at Aravind Eye Hospitals at Madurai, Pondicherry, and Coimbatore in India were enrolled. Study eyes were randomized to topical moxifloxacin 0.5% or topical moxifloxacin 0.5% plus CXL. The primary outcome of the trial was microbiological cure at 24 hours on repeat culture. Secondary outcomes included best spectacle corrected visual acuity at 3 weeks and 3 months, percentage of study participants with epithelial healing at 3 weeks and 3 months, infiltrate and/or scar size at 3 weeks and 3 months, 3-day smear and culture, and adverse events.

RESULTS

Those randomized to CXL had 0.60 decreased odds of culture positivity at 24 hours (95% confidence interval [CI]: 0.10-3.50; P = 0.65), 0.9 logarithm of the minimum angle of resolution lines worse visual acuity (95% CI: -2.8 to 4.6; P = 0.63), and 0.41-mm larger scar size (95% CI: -0.48 to 1.30; P = 0.38) at 3 months. We note fewer corneal perforations or need for therapeutic penetrating keratoplasty in the CXL group.

CONCLUSIONS

We were unable to confirm a benefit to adjuvant CXL in the primary treatment of moderate bacterial keratitis. However, CXL may reduce culture positivity and complication rates; therefore, a larger trial to fully evaluate this is warranted.

TRIAL REGISTRATION

NCT02570321.

Topical chlorhexidine 0.2% versus topical natamycin 5% for fungal keratitis in Nepal: rationale and design of a randomised controlled non-inferiority trial

INTRODUCTION

Fungal infections of the cornea, fungal keratitis (FK), are challenging to treat. Current topical antifungals are not always effective and are often unavailable, particularly in low-income and middle-income countries where most cases occur. Topical natamycin 5% is usually first-line treatment, however, even when treated intensively, infections may progress to perforation of the eye in around a quarter of cases. Alternative antifungal medications are needed to treat this blinding disease.Chlorhexidine is an antiseptic agent with antibacterial and antifungal properties. Previous pilot studies suggest that topical chlorhexidine 0.2% compares favourably with topical natamycin. Full-scale randomised controlled trials (RCTs) of topical chlorhexidine 0.2% are warranted to answer this question definitively.

METHODS AND ANALYSIS

We will test the hypothesis that topical chlorhexidine 0.2% is non-inferior to topical natamycin 5% in a two-arm, single-masked RCT. Participants are adults with FK presenting to a tertiary ophthalmic hospital in Nepal. Baseline assessment includes history, examination, photography, in vivo confocal microscopy and cornea scrapes for microbiology. Participants will be randomised to alternative topical antifungal treatments (topical chlorhexidine 0.2% and topical natamycin 5%; 1:1 ratio, 2-6 random block size). Patients are reviewed at day 2, day 7 (with reculture), day 14, day 21, month 2 and month 3. The primary outcome is the best spectacle corrected visual acuity (BSCVA) at 3 months. Primary analysis (intention to treat) will be by linear regression, with treatment arm and baseline BSCVA prespecified covariates. Secondary outcomes include epithelial healing time, scar/infiltrate size, ulcer depth, hypopyon size, perforation and/or therapeutic penetrating keratoplasty (corneal transplant), positive reculture rate (day 7) and quality of life (EuroQol-5 dimensions, WHO/PBD-VF20, WHOQOL-BREF).

ETHICS AND DISSEMINATION

The Nepal Health Research Council, the Nepal Department of Drug Administration and the London School of Hygiene and Tropical Medicine ethics committee have approved the trial. The results will be presented at local and international meetings and submitted to peer-reviewed journals for publication.

TRIAL REGISTRATION NUMBER

ISRCTN14332621; pre-results.

Filamentous Fungal Keratitis in Taiwan: Based on Molecular Diagnosis

Purpose

To analyze the epidemiological pattern, demographics, risk factors, and treatment outcomes of filamentous fungal keratitis at a tertiary hospital in Taiwan.

Methods

We recruited 65 patients (65 eyes) with culture-proven filamentous fungal keratitis who received diagnosis and treatment at Chang Gung Memorial Hospital between 2015 and 2018. All isolates were examined through conventional morphological identification and subjected to molecular identification with internal transcribed spacer sequencing. Data on patient demographics, predisposing factors, and treatment outcomes were collected.

Results

In total, filamentous fungi belonged to 16 genera were identified. Fusarium spp. (29 cases [44.6%]) was the most commonly isolated organism overall, followed by Colletotrichum spp. and Purpureocillium linacinum (seven cases [10.8% for each]), and Aspergillus spp. (six cases [9.2%]). Some fungi that have not been regarded as human pathogens were also identified, such as Paracremonium and Phellinum. Among 52 (80%) patients with predisposing factors, 30 (46.2%) had trauma. The ulcers of 33 (50.8%) patients resolved with medical treatment only. Additionally, six patients (9.2%) had corneal perforation, and nine patients (13.9%) required therapeutic/destructive surgical interventions including therapeutic penetrating keratoplasty (seven patients) or evisceration (two patients). Only 16 patients (24.6%) had final visual acuity of 20/40 or better.

Conclusions

Through molecular diagnosis, a high diversity of fungal pathogens was revealed along with an increasing incidence of Colletotrichumspp. and Purpureocilliumspp. in Taiwan. The most common risk factor for filamentous fungal keratitis was trauma. The visual outcomes were guarded.

Translational Relevance

The molecular diagnosis provides insight into accurate identification, which affects the epidemiology and diversity of pathogens of filamentous fungal keratitis.

The Prognostic Value of Persistent Culture Positivity in Fungal Keratitis in the Mycotic Antimicrobial Localized Injection Trial

PURPOSE

To evaluate the utility of repeat cultures at days 3 and 7 after starting antifungal medications for predicting outcomes in fungal keratitis.

DESIGN

Prespecified secondary analysis of the randomized clinical Mycotic Antimicrobial Localized Injection trial.

METHODS

Patients presenting to Aravind Eye Hospital, Pondicherry, India, with fungal keratitis and visual acuity worse than 20/70 received topical natamycin and were randomized to either receive intrastromal injection of voriconazole or topical therapy alone. All subjects received corneal cultures at date of presentation, day 3, and day 7. Outcome measures included 3-week and 3-month visual acuity and scar size, corneal perforation, and/or the need for therapeutic penetrating keratoplasty (TPK). Visual acuity and scar size were analyzed with multiple linear regression controlling for baseline measures. Survival analysis was used to analyze the risk of corneal perforation and/or need for TPK.

RESULTS

Of the 70 study subjects with fungal keratitis, 25 of 69 (36%) remained culture positive at day 3, and 20 of 62 (32%) were culture positive at day 7. Culture positivity at day 3 conferred a hazard ratio of 2.8 for requiring TPK (P = .03) but was not a statistically significant predictor of perforation, scar size, or final visual acuity. Culture positivity at day 7 had a hazard ratio of 3.5 for requiring TPK (P = .003). Those with positive cultures at day 7 had on average 3 logMAR lines worse visual acuity at 3 months (95% confidence interval 0.9 to 5.2 logMAR lines, P = .006) and 1.1 mm larger scar size at 3 months after controlling for baseline measures (95% confidence interval 0.1 to 2.2 mm; P = .03).

CONCLUSIONS

While not as predictive as day 7 cultures, culture positivity at day 3 after starting treatment is a significant predictor of the need for TPK in patients with moderate-to-severe filamentous fungal keratitis. This has applications for risk stratification, and may facilitate earlier consideration of TPK in high-risk patients.

Tintelnotia destructans as an emerging opportunistic pathogen: First case of T. destructans superinfection in herpetic keratitis

Purpose

Only recently Tintelnotia was described as a new genus in the Phaeosphaeriaceae family of fungi containing two species, T. opuntiae and T. destructans. Until now, T. destructans keratitis was associated with contact lens wear and ocular trauma. We present the first case of T. destructans keratomycosis presenting as a superinfection in herpetic keratitis.

Observations

We present a case of a 53-year-old woman who presented with a unilateral keratitis since 3 weeks without history of trauma or contact lens wear, not responding to topical ofloxacin. Polymerase Chain Reaction (PCR) of the corneal ulcer was positive for Herpes Simplex Virus type 1 (HSV-1). Signs and symptoms progressively improved after starting topical and systemic antiviral therapy. Six weeks later however, our patient presented with a new white infiltrate in the previous herpetic epithelial defect. In vivo confocal microscopy showed fungal hyphae and culture from corneal scrapings identified a hyphomycete. Intensive antimycotic therapy could not prevent a corneal perforation 1 week later. Penetrating keratoplasty was performed with intracameral injection of amphotericin B. Culture of the corneal button and PCR and sequence analysis on the fungal isolate confirmed the diagnosis of T. destructans keratomycosis. Six months after penetrating keratoplasty, biomicroscopy showed a clear graft without recurrence of fungal activity.

Conclusions and importance

T. destructans is an emerging opportunistic pathogen causing severe keratomycosis. Despite intensive antimycotic therapy, rapid progression to corneal perforation can be seen. Early diagnosis using confocal microscopy, fungal culture and PCR can allow prompt initiation of treatment, which should be guided by in vitro susceptibility testing.

Combined Intrastromal Voriconazole and Amphotericin B Treatment for Persistent Fungal Keratitis

PURPOSE

To evaluate the clinical outcomes of combined intrastromal voriconazole and intrastromal amphotericin B for the treatment of persistent fungal keratitis.

METHOD

Patients who received combined corneal intrastromal voriconazole (0.05 mg/0.1 mL) and intrastromal liposomal amphotericin B (0.01 mg/0.1 mL) injections in addition to topical therapy for treatment of persistent fungal keratitis were included in the study. Persistence was described as no improvement or progression in the clinical findings despite treatment with combined topical voriconazole (1 mg/0.1 mL) and topical amphotericin B drops (0.15 mg/0.1 mL) hourly for at least 10 days. The healing of keratitis was considered as the complete closure of epithelial defect with complete resolution of a corneal infiltrate.

RESULTS

Thirty-two eyes of 32 patients who met the inclusion criteria were included in this study. Predominant organisms in fungal isolates were Aspergillus species. Combination therapy of intrastromal amphotericin B and intrastromal voriconazole in addition to topical therapy resulted in complete resolution of persistent fungal keratitis in 28 (87.5%) patients. The mean number of intrastromal injections was 9.3±6.4 and ranged from 1 to 18. The mean best-corrected visual acuity values improved from 2.17±0.43 to 1.76±0.77 logarithm of the minimum angle of resolution units (P=0.003). The mean duration of complete epithelial closure was 45.3±16.3 days. Four patients required therapeutic penetrating keratoplasty because of persistence of fungal keratitis (3 patients) and progression of keratitis (1 patient). There was no need for evisceration.

CONCLUSION

Combination therapy with intrastromal voriconazole and intrastromal amphotericin B may be an effective adjunct treatment for persistent fungal keratitis.

[Scedosporium apiospermum-a rare pathogen of keratomycosis]

This article presents the case of a 44-year-old contact lens wearer who presented with acute keratitis resistant to antibacterial treatment in the right eye. The anterior segment of the eye showed circular conjunctival hyperemia, a corneal white cell infiltrate with radiating margins and a central corneal erosion. Microbiological investigation of a corneal scraping revealed growth of Scedosporium apiospermum. Intensive antimycotic treatment and several corneal collagen crosslinking procedures were performed; however, because of rapidly evolving necrotizing ulcerative keratitis, a keratoplasty à chaud was carried out.

The Spectrum of Microbial Keratitis: An Updated Review

Background:

In microbial keratitis, infection of the cornea can threaten vision through permanent corneal scarring and even perforation resulting in the loss of the eye. A literature review was conducted by Karsten, Watson and Foster (2012) to determine the spectrum of microbial keratitis. Since this publication, there have been over 2600 articles published investigating the causative pathogens of microbial keratitis.

Objective:

To determine the current spectrum of possible pathogens implicated in microbial keratitis relative to the 2012 study.

Methods:

An exhaustive literature review was conducted of all the peer-reviewed articles reporting on microbial pathogens implicated in keratitis. Databases including MEDLINE, EMBASE, Scopus and Web of Science were searched utilising their entire year limits (1950-2019).

Results:

Six-hundred and eighty-eight species representing 271 genera from 145 families were implicated in microbial keratitis. Fungal pathogens, though less frequent than bacteria, demonstrated the greatest diversity with 393 species from 169 genera that were found to cause microbial keratitis. There were 254 species of bacteria from 82 genera, 27 species of amoeba from 11 genera, and 14 species of virus from 9 genera, which were also identified as pathogens of microbial keratitis.

Conclusion:

The spectrum of pathogens implicated in microbial keratitis is extremely diverse. Bacteria were most commonly encountered and in comparison, to the review published in 2012, further 456 pathogens have been identified as causative pathogens of microbial keratitis. Therefore, the current review provides an important update on the potential spectrum of microbes, to assist clinicians in the diagnosis and treatment of microbial keratitis.

The impact of microbial keratitis on quality of life in Uganda

Background

Microbial keratitis (MK) is a frequent cause of sight loss in sub-Saharan Africa. However, no studies have formally measured its impact on quality of life (QoL) in this context.

Methods

As part of a nested case–control design for risk factors of MK, we recruited patients presenting with MK at two eye units in Southern Uganda between December 2016 and March 2018 and unaffected individuals, individually matched for sex, age and location. QoL was measured using WHO Health-Related and Vision-Related QoL tools (at presentation and 3 months after start of treatment in cases). Mean QoL scores for both groups were compared. Factors associated with QoL among the cases were analysed in a linear regression model.

Results

215 case-controls pairs were enrolled. The presentation QoL scores for the cases ranged from 20 to 65 points. The lowest QoL was visual symptom domain; mean 20.7 (95% CI 18.8 to 22.7) and the highest was psychosocial domain; mean 65.6 (95% CI 62.5 to 68.8). At 3 months, QoL scores for the patients ranged from 80 to 90 points while scores for the controls ranged from 90 to 100. The mean QoL scores of the cases were lower than controls across all domains. Determinants of QoL among the cases at 3 months included visual acuity at 3 months and history of eye loss.

Conclusion

MK severely reduces QoL in the acute phase. With treatment and healing, QoL subsequently improves. Despite this improvement, QoL of someone affected by MK (even with normal vision) remains lower than unaffected controls.

Epidemiology of Microbial Keratitis in Uganda: A Cohort Study

Purpose

To describe the epidemiology of Microbial Keratitis (MK) in Uganda.

Methods

We prospectively recruited patients presenting with MK at two main eye units in Southern Uganda between December 2016 and March 2018. We collected information on clinical history and presentation, microbiology and 3-month outcomes. Poor vision was defined as vision < 6/60).

Results

313 individuals were enrolled. Median age was 47 years (range 18–96) and 174 (56%) were male. Median presentation time was 17 days from onset (IQR 8–32). Trauma was reported by 29% and use of Traditional Eye Medicine by 60%. Majority presented with severe infections (median infiltrate size 5.2 mm); 47% were blind in the affected eye (vision < 3/60). Microbiology was available from 270 cases: 62% were fungal, 7% mixed (bacterial and fungal), 7% bacterial and 24% no organism detected. At 3 months, 30% of the participants were blind in the affected eye, while 9% had lost their eye from the infection. Delayed presentation (overall p = .007) and prior use of Traditional Eye Medicine (aOR 1.58 [95% CI 1.04–2.42], p = .033) were responsible for poor presentation. Predictors of poor vision at 3 months were: baseline vision (aOR 2.98 [95%CI 2.12–4.19], p < .0001), infiltrate size (aOR 1.19 [95%CI 1.03–1.36], p < .020) and perforation at presentation (aOR 9.93 [95% CI 3.70–26.6], p < .0001).

Conclusion

The most important outcome predictor was the state of the eye at presentation, facilitated by prior use of Traditional Eye Medicine and delayed presentation. In order to improve outcomes, we need effective early interventions.