The clinical and microbiological features and outcomes of fungal keratitis over 9 years in Sydney, Australia

From the diagnosis of infectious keratitis to discriminating fungal subtypes; a deep learning-based study

Infectious keratitis (IK) is a major cause of corneal opacity. IK can be caused by a variety of microorganisms. Typically, fungal ulcers carry the worst prognosis. Fungal cases can be subdivided into filamentous and yeasts, which shows fundamental differences. Delays in diagnosis or initiation of treatment increase the risk of ocular complications. Currently, the diagnosis of IK is mainly based on slit-lamp examination and corneal scrapings. Notably, these diagnostic methods have their drawbacks, including experience-dependency, tissue damage, and time consumption. Artificial intelligence (AI) is designed to mimic and enhance human decision-making. An increasing number of studies have utilized AI in the diagnosis of IK. In this paper, we propose to use AI to diagnose IK (model 1), differentiate between bacterial keratitis and fungal keratitis (model 2), and discriminate the filamentous type from the yeast type of fungal cases (model 3). Overall, 9329 slit-lamp photographs gathered from 977 patients were enrolled in the study. The models exhibited remarkable accuracy, with model 1 achieving 99.3%, model 2 at 84%, and model 3 reaching 77.5%. In conclusion, our study offers valuable support in the early identification of potential fungal and bacterial keratitis cases and helps enable timely management.

Sustained Release of Voriconazole Using 3D-Crosslinked Hydrogel Rings and Rods for Use in Corneal Drug Delivery

Corneal disorders and diseases are prevalent in the field of clinical ophthalmology. Fungal keratitis, one of the major factors leading to visual impairment and blindness worldwide, presents significant challenges for traditional topical eye drop treatments. The objective of this study was to create biocompatible 3D-crosslinked hydrogels for drug delivery to the cornea, intending to enhance the bioavailability of ophthalmic drugs. Firstly, a series of flexible and porous hydrogels were synthesized (free-radical polymerization), characterized, and evaluated. The materials were prepared by the free-radical polymerization reaction of 1-vinyl-2-pyrrolidinone (also known as N-vinylpyrrolidone or NVP) and 1,6-hexanediol dimethacrylate (crosslinker) in the presence of polyethylene glycol 1000 (PEG-1000) as the porogen. After the physicochemical characterization of these materials, the chosen hydrogel demonstrated outstanding cytocompatibility in vitro. Subsequently, the selected porous hydrogels could be loaded with voriconazole, an antifungal medication. The procedure was adapted to realize a loading of 175 mg voriconazole per ring, which slightly exceeds the amount of voriconazole that is instilled into the eye via drop therapy (a single eye drop corresponds with approximately 100 mg voriconazole). The voriconazole-loaded rings exhibited a stable zero-order release pattern over the first two hours, which points to a significantly improved bioavailability of the drug. Ex vivo experiments using the established porcine eye model provided confirmation of a 10-fold increase in drug penetration into the cornea (after 2 h of application of the hydrogel ring, 35.8 ± 3.2% of the original dose is retrieved from the cornea, which compares with 3.9 ± 1% of the original dose in the case of eye drop therapy). These innovative hydrogel rods and rings show great potential for improving the bioavailability of ophthalmic drugs, which could potentially lead to reduced hospitalization durations and treatment expenses.

Case Series of Rare Fungal Keratitides: Experiences from a Quaternary Eye Hospital in Sydney, Australia

The present article reports on the management of six different and rare cases of fungal keratitides, two of which have never been documented in previous literature. This is a case series of six patients with rare fungal keratitides managed at a quaternary eye referral unit, Sydney Eye Hospital, Australia over a period of 7 months (May to December, 2022). The order of occurrence of fungi isolated was Scedosporium apiospermum, Lomenstospora prolificans, Cladosporium spp., Paecilomyces, Syncephalastrum racemosum and Quambalaria spp. A combination of medical and surgical interventions was employed, including topical and systemic anti-fungal therapy, with one requiring therapeutic penetrating keratoplasty and another eventuating in evisceration. Two patients were successfully treated with corneal debridement and two others required pars plana vitrectomy with anterior chamber washout. It is important to remain vigilant with monitoring patient symptoms and correlating with clinical signs to guide antifungal therapy even in the context of confirmed culture and sensitivity results.

Intrastromal Injections in the Management of Infectious Keratitis

Infectious keratitis is a major global cause of vision loss and blindness. Prompt diagnosis and targeted antibiotic treatment are crucial for managing the condition. Topical antimicrobials are the most effective therapy for bacterial keratitis, but they can lead to unsatisfactory results due to ocular perforation, scarring, and melting. Intrastromal injection is a newer technique for delivering antimicrobials directly to the site of infection and has been successful in treating severe, treatment-resistant infectious keratitis, especially when surgery is not recommended. In cases where deep stromal disease is resistant to topical treatment, intrastromal antimicrobial injections may be necessary to achieve higher drug concentration at the infection site. However, the use of intrastromal antibiotics is limited, as topical antibacterial agents have better penetration than antifungal agents. Bacterial and fungal keratitis have been extensively researched for intrastromal medication injections, while there is limited evidence for viral keratitis. This review emphasizes the potential of intrastromal antimicrobial injections as an alternative for managing severe refractory infectious keratitis. The technique offers direct targeting of the infection site and faster resolution in some cases compared to topical therapy. However, further research is needed to determine the safest antimicrobials options, minimal effective doses, and concentrations for various pathogens. Intrastromal injections may serve as a non-surgical treatment option in high-risk cases, with benefits including direct drug delivery and reduced epithelial toxicity. Despite promising findings, more studies are required to confirm the safety and efficacy of this approach.

Modern Technologies in Diagnosis of Fungal Keratitis (Review)

Traumas and infectious diseases of the eye play a leading role in the development of corneal blindness responsible for 1.5-2 million cases of vision loss per year. To date, the issue of reducing the incidence of fungal keratitis is acute and needs to be solved worldwide. Trauma as a risk factor for corneal fungal disease is thought to be prevalent in developing countries due to agricultural involvement, while in developed countries the onset of the disease is predisposed by medical advances such as contact vision correction and modern ophthalmic surgery. Thorough analysis of the pathogenesis gives the possibility to describe the action of fungal enzymes, biofilm formation, and the resistance mechanism, which on the one hand explains the aggressive course of the disease and difficulties in its diagnosis, and on the other hand, it encourages searching for new methods of diagnosis and treatment. The non-specific clinical picture of fungal keratitis, the variety and availability of antibiotics nowadays become an obstacle for rapid detection of this pathology. Low public awareness and late visit to an ophthalmologist are also a barrier to successful combating the increasing incidence of fungal keratitis. Belated diagnosis, increasing resistance of fungi to antibiotics, and lack of registered antifungal ophthalmic drugs justify poor treatment efficacy resulting in decreased visual acuity or vision loss. Existing diagnostic methods need systematization and detailed comparison, identifying the advantages and disadvantages of each. This review considers causative agents and their influence on pathogenesis of the disease, describes difficulties of fungal keratitis diagnosis and possible ways of overcoming these problems using new developments, and also outlines further prospects of research in this direction.

Presumed Microbial Keratitis Cases Resulting in Evisceration and Enucleation in Sydney, Australia

PURPOSE

Describe presumed microbial keratitis cases resulting in evisceration/enucleation from 2012 to 2016 in Sydney, Australia.

METHODS

A retrospective case review included 33 patients. Cases were identified from pathology and hospital coding data. Sociodemographic and clinical details were collated.

RESULTS

Mean age was 79 years (range: 38-100 years), and 64% female. There were 30 eviscerations and 3 enucleations, at a median time of 8 days (range: 1-270 days) due to endophthalmitis (n = 15, 45%). Major ocular associated factors included topical corticosteroid use in 12 patients (36%), exposure keratopathy in 4 (12%), ectropion in 3 (9%), degenerative corneal disease in 3 (9%), and corneal graft in 2 (6%). Pseudomonas aeruginosa was the most common isolate with no reports of antimicrobial resistance.

CONCLUSIONS

Educating elderly patients with a history of topical corticosteroid use, corneal or ocular surface disease about prompt hospital presentation and treatment of microbial keratitis may decrease the probability of losing the eye.

Molecular characterization of fungal endophthalmitis and keratitis caused by yeasts

Candida species are the most common causes of sight-threatening fungal ocular infections in temperate regions of the world. Despite their relevance, little is known about the emergence of novel species and the molecular epidemiology of these infections. Here, we molecularly characterized 38 yeast isolates collected from patients diagnosed with endophthalmitis or keratitis at Massachusetts Eye and Ear from 2014 to 2021. Sequencing of the ITS1-5.8S-/ITS2 regions demonstrated that this population of yeasts was dominated by Candida spp. (37 out of 38; 97%), with 58% of the cases caused by C. albicans (n = 22) and the remaining by emerging non-albicans species, predominantly by C. parapsilosis (n = 8) and C. dubliniensis (n = 6). One isolate each was identified as C. tropicalis and Clavispora lusitaniae. Interestingly, all C. dubliniensis were isolated from endophthalmitis and most C. parapsilosis from keratitis. Multilocus sequence typing analysis of C. albicans showed a prevalence of CC-1 isolates that has DST69 as the putative founder, with 64% of them belonging to this clonal complex (CC). Isolates grouped within this cluster were more predominant in endophthalmitis (10 out of 14; 71%). One C. albicans CC-1 isolate was multi-azole resistant. In conclusion, we observed that nearly half of the ocular infections caused by yeasts are associated with C. albicans, with evidence for the emergence of non-albicans species that are differentially enriched in distinct ocular niches. Candida albicans isolates clustered within the predominant CC-1 group were particularly more common in endophthalmitis, demonstrating a potential pattern of ocular disease enrichment within this clade.

Fungal keratitis treated with a combination of traditional Chinese medicine and Western medicine: A case report

RATIONALE

Currently, the primary treatments for fungal keratitis (FK) are drugs and surgery. However, drug treatment has low efficacy and many side effects, and surgical treatment is costly. Therefore, it is critical to develop a new method of FK treatment. This report describes a 56-year-old male patient with FK who was treated with a combination of traditional Chinese medicine (TCM) and Western medicine with noticeable results and few side effects.

PATIENT CONCERNS

The main symptoms were blurred vision in the right eye and pain. On the corneal surface, a large area of ulcer with a turbid margin was visible, along with an oral ulcer. Additionally, the patient was afraid of corneal transplantation due to financial constraints.

DIAGNOSES

The case was diagnosed as FK. In vivo confocal microscopy is the first choice for the diagnosis of this condition. Corneal ulcer was infiltrated with numerous inflammatory cells and dendritic fungal hyphae, as determined by in vivo confocal microscopy.

INTERVENTIONS

Early in his illness, the patient was treated with only Western medicine, which resulted in poor outcomes and severe adverse reactions. Corneal transplantation was recommended by the first hospital. The patient was later transferred to our hospital for treatment with TCM decoction.

OUTCOMES

After 21 days of treatment, the corneal ulcer of the patient became shallower, his vision improved, and his discomfort disappeared. Due to financial concerns, the patient and his family requested early discharge, so no follow-up disease information was obtained. However, when analyzing the disease development process in the hospital, the combination of TCM and Western medicine had obvious effects and a high level of safety.

LESSONS

This case report shows that TCM is safe and effective in the treatment of FK and is worthy of promotion. However, in practice, we found that TCM is better for patients with early FK, so early diagnosis of FK is crucial.

Trends of ocular fungal infections in North China (2001-2020)

OBJECTIVES

To analyze the epidemiologic features, culture positivity, the fungal spectrum of different sites of ocular infection in North China over 20 years from 2001 to 2020.

METHODS

11, 635 patients suspected of ocular fungal infection were reviewed. The demographic profile, fungal positive culture rate among different sites, the distribution, and trends of main pathogens among cornea and intraocular fluid were analyzed.

RESULTS

Among 11, 635 samples, the positive culture rate of ocular fungal infection was 23.6%. Most of samples (83.1%) were from cornea, and their culture positivity was 26.9%. Fungal keratitis occurred more often during the harvesting season (October to December; 34.0%) than in other seasons (average: 22.0%). Fusarium sp. (53.2%), Aspergillus sp. (15.9%) and Alternaria sp. (12.5%) were the most common fungal species of ocular mycotic infections in the past two decades in north China. 2562 organisms were identified from cornea, of which 1443 (56.3%) were Fusarium sp., 403 (15.7%) and 329 (12.8%) were Aspergillus sp., and Alternaria sp., respectively. Of the 120 fungi isolated from the intraocular fluid, the most common was Aspergillus sp. (33.3%), followed by Fusarium sp. (24.2%) and Candida sp. (15.0%).

CONCLUSIONS

Fusarium sp., Aspergillus sp. and Alternaria sp. were the most common organisms in cases of fungal keratitis, while Aspergillus sp., Fusarium sp. and Candida sp. were the most frequent isolates for fungal endophthalmitis.

Use of Topical Cyclosporine 0.1% in Therapeutic Penetrating Keratoplasty for Fungal Keratitis

PURPOSE

The efficacy and safety of topical cyclosporine 0.1% in preventing early graft failure after therapeutic penetrating keratoplasty (TPK) in eyes with fungal keratitis were evaluated.

METHODS

This prospective case series included patients with fungal keratitis undergoing TPK from May to December 2019 who were treated with cyclosporine A 0.1% eye drops (tCSA group). We compared the outcome with a historical cohort of patients who were treated conventionally (CT group) with topical prednisolone acetate 1% eye drops started 3 weeks after surgery.

RESULTS

There were 20 patients (male: 13; female: 7) in the tCSA group and 28 patients in the CT group (male: 23; female: 5). The number of clear grafts 3 months postoperatively was 10 (50%) in the tCSA group and 4 (14.3%) in the CT group ( P = 0.011). The mean logarithm of the minimum angle of resolution best-corrected visual acuity was 1.49 ± 0.74 in the tCSA group and 2.10 ± 0.62 in the CT group ( P = 0.003). There were 5 patients (17.9%) with recurrence of the primary fungal infection in the CT group, 4 of whom were using topical prednisolone. There was no recurrence in the tCSA group. A logistic regression analysis revealed higher odds of a clear graft at 3 months postoperatively with topical cyclosporine 0.1% [odds ratio: 14.35 (95% confidence interval, 2.38-86.5), P = 0.004].

CONCLUSIONS

Postoperative treatment with topical cyclosporine 0.1% seems to increase graft survival and postoperative vision with reduced risk of recurrence of primary infection in eyes with fungal keratitis undergoing TPK.

Mixed Fungal Biofilms: From Mycobiota to Devices, a New Challenge on Clinical Practice

Most current protocols for the diagnosis of fungal infections are based on culture-dependent methods that allow the evaluation of fungal morphology and the identification of the etiologic agent of mycosis. Most current protocols for the diagnosis of fungal infections are based on culture-dependent methods that enable the examination of the fungi for further identification of the etiological agent of the mycosis. The isolation of fungi from pure cultures is typically recommended, as when more than one species is identified, the second agent is considered a contaminant. Fungi mostly survive in highly organized communities that provoke changes in phenotypic profile, increase resistance to antifungals and environmental stresses, and facilitate evasion from the immune system. Mixed fungal biofilms (MFB) harbor more than one fungal species, wherein exchange can occur that potentialize the effects of these virulence factors. However, little is known about MFB and their role in infectious processes, particularly in terms of how each species may synergistically contribute to the pathogenesis. Here, we review fungi present in MFB that are commensals of the human body, forming the mycobiota, and how their participation in MFB affects the maintenance of homeostasis. In addition, we discuss how MFB are formed on both biotic and abiotic surfaces, thus being a significant reservoir of microorganisms that have already been associated in infectious processes of high morbidity and mortality.

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.

Clinical and microbiological analysis of fungal keratitis in Toronto, Canada: A 20-year study

Fungal keratitis is a devastating and difficult-to-treat ocular infection with high morbidity. Understanding geographic microbiological and clinical trends helps to guide rapid and effective treatment. We therefore report the characteristics and outcomes of fungal keratitis in Toronto, Canada over a twenty-year period. An electronic search of microbiology records at University Health Network, Toronto, ON, Canada identified all patients with positive corneal fungal culture over a 20-year period seen at our tertiary referral cornea practice. Review of corresponding patient charts identified demographic and microbiological details, clinical course, treatment regimen, and final outcomes associated with each episode of culture-positive fungal keratitis. Forty-six patients with fifty-one discrete fungal keratitis episodes were included. Five patients experienced recurrent fungal keratitis. Candida species accounted for 60.8% of positive fungal cultures, followed by Filamentous species at 35.3%. Preferred initial anti-fungal treatment was topical amphotericin at 36.7% followed by topical voriconazole at 32.6%. Surgical intervention was required in 48.9% with therapeutic penetrating keratoplasty being the most common procedure (22.4%). Final visual acuity (VA) of < 20/200 was attributed to 58% of patients in this study. Risk factors for poor outcomes included poor VA, topical steroid use at presentation, Candida involvement, history of ocular surface disease, organic ocular trauma, or prior corneal transplantation. Candida is the most frequent keratomycotic pathogen in Toronto. Risk factors for poor visual outcome include prior corneal transplantation, ocular surface disease/trauma, or pre-existing topical steroid use. Early suspicion, diagnosis and treatment are paramount for best clinical outcomes.

Microbiological Profiles of Ocular Fungal Infection at an Ophthalmic Referral Hospital in Southern China: A Ten-Year Retrospective Study

Purpose

Methods

Results

Conclusion

Outcomes of Microbial Keratitis Cases Resistant to Antimicrobials in Sydney, Australia

PURPOSE

The purpose of this study was to describe demographics, predisposing factors, clinical features, treatment, and outcomes of microbial keratitis cases resistant to antimicrobials.

METHODS

A retrospective case series was conducted. All patients with microbial keratitis resistant to antimicrobials who underwent a corneal scrape and culture from 2012 to December 2016 at the Sydney Eye Hospital were included. Cases were identified from pathology and hospital coding data. Coagulase-negative staphylococci (CoNS), Staphylococcus aureus (S. aureus), and Corynebacterium spp. resistant to cefalotin, chloramphenicol, ciprofloxacin, or gentamicin were analyzed.

RESULTS

One hundred fifteen episodes had a resistant CoNS, 24 S. aureus, and 12 Corynebacterium spp. Antimicrobial resistance was associated with older women (67%, median age 83 years) with Corynebacterium spp. (P < 0.001), corneal graft, and previous topical steroid use. Larger epithelial defects (P = 0.203) and infiltrates (P = 0.180) were more likely to be associated with Corynebacterium spp., but not statistically significant. At the initial and final visits, resistant S. aureus (75% vs. 67%) and Corynebacterium spp. (78% vs. 80%) cases were more likely to be classified as blind (>3/60) compared with CoNS (45% vs. 28%) (P = 0.011 vs. P = 0.004). Corneal perforation occurred more often in resistant S. aureus cases (P < 0.001), whereas slow and nonhealing epithelial defects needing other procedures were more likely to occur with resistant Corynebacterium spp. (P < 0.001).

CONCLUSIONS

Patients with resistant CoNS were younger and presented with smaller ulcers and moderate vision loss. Visual and clinical outcomes were significantly better for resistant CoNS than for those with resistant S. aureus or Corynebacterium spp.

Case Report: A Rare Fungal Keratitis Caused by Plectosphaerella Cucumerina

PURPOSE

To report a rare case of fungal keratitis caused by Plectosphaerella cucumerina.

METHODS

This study retrospectively reviewed the medical records of a case of fungal keratitis.

RESULTS

Silt-lamp biomicroscopy revealed corneal infiltration and epithelial defects. Anterior segment optical coherence tomography (AS-OCT) and in vivo confocal microscopy (IVCM) were performed to assist in the diagnosis and evaluate corneal conditions. The isolate was identified as Plectosphaerella cucumerina by MALDI-TOF mass spectrometry. The patient was treated with topical 5% pimaricin and oral voriconazole for 1 month and recovered.

CONCLUSION

Fungal keratitis caused by Plectosphaerella cucumerina is rare. AS-OCT and IVCM can help locate the lesion and diagnose fungal keratitis. Furthermore, MALDI-TOF mass spectrometry showed potential prospects in the identification of filamentous fungi. Plectosphaerella cucumerina rarely infects humans and is sensitive to antifungal agents such as pimaricin and voriconazole.

Clinical Characteristics and Outcomes of Rare Fungal Keratitis Caused by Verticillium dahliae

PURPOSE

To observe clinical characteristics and treatment outcomes of fungal keratitis caused by Verticillium dahliae.

METHODS

Clinical data of 7 patients diagnosed as fungal keratitis cause by Verticillium dahliae were retrospectively analyzed. The clinical manifestations, mycology, in vitro antifungal susceptibility, treatment regimens and prognoses of the patients were evaluated.

RESULTS

All 7 patients were farm worker, of which 5 cases were caused by plant trauma. The corneal ulcer had a round shape and a relatively limited range with the diameters mainly in the range of 2-7 mm. The stromal infiltration was mild, and had no pseudopodia, mossiness or endothelial plaques. Intact hyphaes were detected in corneal scrapings and confocal microscopy, isolates were identified by morphology and by sequencing the internal transcribed spacer region of ribosomal DNA. In vitro antifungal susceptibility testing showed that the most sensitive antifungal drug was Amphotericin B. In the 6 patients with an ulcer less than 2/3 of the corneal thickness, the ulcer healed after 18 days of antifungal treatment only in one eye. The other five patients underwent corneal ulcer debridement or conjunctival flap covering surgery. The remaining one patient with ulcer depth more than 2/3 of the corneal thickness underwent lamellar keratoplasty.

CONCLUSION

Fungal keratitis caused by Verticillium dahliae has typical signs of a mild inflammatory response, and is not sensitive to antifungal drugs. It is recommended that patients undergo corneal ulcer debridement as soon as possible to promote rapid healing of the ulcers.

Results From the German Fungal Keratitis Registry: Significant Differences Between Cases With and Without a History of Contact Lens Use

PURPOSE

Fungal keratitis (FK) is a serious ophthalmic disease with a potentially devastating outcome that seems to be increasing in recent years. The use of contact lenses (CLs) was evaluated as a risk factor for FK to determine possible differences in course and outcome.

METHODS

Data from 173 cases reported in the German FK registry until August 2019 were evaluated regarding CL behavior, other ophthalmological and general risk factors, age, sex, identified pathogens, conservative and surgical therapy, visual acuity, and findings at admission and follow-up.

RESULTS

One hundred seventy-four eyes from 173 patients between 2000 and 2019 were included [64.4% women, median age 54 (39; 72) years]; 49.7% wore CL, of which 81.3% were soft CL, and 50.3% had no history of contact lens use (NCL). CL users were significantly more often women and otherwise healthy (CL: 80.2% vs. NCL: 48.9%; P < 0.0001). The spectrum of pathogens among CL users showed a significantly higher proportion of infections with filamentous pathogens, in particular Fusarium sp. (total filament: CL 69.8% vs. NCL 27.3%; P = 0.0001; Fusarium sp.: CL 50.0% vs. NCL 14.8%; P < 0.0001). Overall, 54.6% required keratoplasty and 8.6% enucleation.

CONCLUSIONS

CLS are the most important risk factor for FK in Germany. With CLs, typically, the infection is caused by molds, and patients are comparably younger and otherwise healthy. Often, extensive surgery is needed. To evaluate changes in the pathogen and resistance spectrum and to further monitor possible CL-related risk factors, a consistent collection of data remains paramount.

Pathogenic Aspergillus and Fusarium as important causes of blinding corneal infections - the role of neutrophils in fungal killing, tissue damage and cytokine production

Filamentous fungi Aspergillus and Fusarium species are major causes of visual impairment and blindness in immune competent individuals. Once conidia penetrate the corneal epithelium and enter the stroma, they undergo germination, and exposure of cell wall components induces a pronounced neutrophil-rich cellular infiltrate. In this review, we discuss Aspergillus and novel Fusarium virulence factors that are required for corneal infection, and describe the multiple functions of neutrophils in limiting hyphal growth in the cornea. This review will also discuss the role of neutrophils as an important source of cytokines in fungal keratitis, and highlight recent studies identifying unique characteristics of neutrophil secretion of IL-1α and IL-1β.

Clinical Manifestations and Prognostic Factors of Fungal Keratitis: Analysis in Patients Over a 20-year Period

Purpose: To describe the clinical manifestations, causative organisms, treatment, and prognostic factors of fungal keratitis based on analysis of patients over the past 20 years. Methods: A total of 177 patients (177 eyes) with fungal keratitis, who were diagnosed by smears and cultures, were reviewed retrospectively. Sex, age, predisposing factors, causative organisms, clinical manifestations, treatment, and prognosis were evaluated. The patients were divided into three groups: only potassium hydroxide (KOH)-positive, only culture-positive, and KOH- and culture-positive. Logistic regression was performed to identify the factors associated with a poor clinical outcome. Results: The mean age of the patients was 67.4 ± 11.3 years; 107 (60.5%) patients were men. The most common predisposing factor was ocular trauma (57.6%), especially by plants (29.4%). The most prevalent filamentous fungi were Fusarium species (31.6%, 49 isolates), and the most prevalent yeasts were Candida species (11.0%, 17 isolates). In cases of bacterial and fungal keratitis, filamentous fungus with Gram-positive bacterial infection (70.7%, 29/41) was the most common presentation. Visual improvement after treatment was common in the KOH-positive group (79.2%, 19/24), while visual deterioration after treatment was common in the culture-positive group (40.4%, 36/89). Previous ocular disease (odds ratio [OR]: 3.744, p = 0.010), hypopyon (OR: 2.941, p = 0.030), and surgical treatment (OR: 24.482, p < 0.001) were risk factors for a poor clinical outcome in the multivariate logistic regression model. Conclusions: Clinical prognosis was good in the KOH-positive only group, but poor in the culture-positive group. If fungal keratitis is suspected, diagnostic KOH staining and culture tests should be performed initially. Early intensive antifungal medical treatments are necessary for patients with risk factors for poor clinical outcomes.

The Clinical Features and Prognostic Factors for Treatment Outcomes of Dematiaceous Fungal Keratitis over 9 Years at a Tertiary Eye Care in Northern Thailand

Dematiaceous fungal keratitis is an important etiology of visual loss, particularly in an agricultural society. From a retrospective review of medical records from 2012 to 2020, 50 keratitis cases of cultured-positive for dematiaceous fungi were presented at a tertiary care hospital in Northern Thailand. The study aimed to identify the isolated causative dematiaceous species using the PCR technique and to explore their related clinical features, including treatment prognoses. Sequencing of the amplified D1/D2 domains and/or ITS region were applied and sequenced. Of the 50 dematiaceous fungal keratitis cases, 41 patients were males (82%). In most cases, the onset happened during the monsoon season (June to September) (48%). The majority of the patients (72%) had a history of ocular trauma from an organic foreign body. The most common species identified were Lasiodiplodia spp. (19.35%), followed by Cladosporium spp. and Curvularia spp. (12.90% each). About half of the patients (52%) were in the medical failure group where surgical intervention was required. In summary, ocular trauma from an organic foreign body was the major risk factor of dematiaceous fungal keratitis in Northern Thailand. The brown pigmentation could be observed in only 26%. Significant prognostic factors for medical failure were visual acuity at presentation, area of infiltrate, depth of the lesions, and hypopyon.

Recent developments in less known and multi-resistant fungal opportunists

Fungal infections have increased in recent years due to host factors, such as oncohaematological and transplant-related disorders, immunosuppressive therapy, and AIDS. Additionally, molecular and proteomic facilities have become available to identify previously unrecognizable opportunists. For these reasons, reports on less-known and recalcitrant mycoses, such as those caused by black fungi, hyaline filamentous fungi, coelomycetes, Mucorales, and non-Candida yeasts have emerged. In this review, novel taxonomy in these groups, which often are multi-resistant to one or several classes of antifungals, is discussed. Clinical presentations, diagnosis and current treatment of some major groups are summarised.

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.

Fungal keratitis at a tertiary eye care in Northern Thailand: Etiology and prognostic factors for treatment outcomes

PURPOSE

To evaluate etiology and prognostic factors for treatment outcomes of fungal keratitis (FK).

METHODS

Culture-positive FK patients between 2012 and 2017 were reviewed. Treatment outcomes were categorized into success (resolved within two weeks), slow response and medication failure (no improvement or required surgery). Etiology and risk factors for poor treatment outcomes were analyzed.

RESULTS

A total of 113 eyes of 113 patients (77% males) were recruited. Ocular trauma (69.0%) was the most common predisposing factor. Of this, 80% were exposed to organic foreign bodies. The most common pathogen was Fusarium spp. (45.2%), while dematiaceous fungi were discovered in 29.6%. Medical treatment was successful in 24.8% of eyes, while 29.2% had a slow response and 42.5% failed medication. Therapeutic keratoplasty was performed in 22.1% of eyes and 11.5% eventually required eye removal. Significant risk factors for medication failure were advanced age (P = 0.005), delayed antifungal treatment (P = 0.038) and large-size lesion (P = 0.003).

CONCLUSIONS

Ocular trauma was the major predisposing factor of FK in the Northern Thailand. Fusarium was the most common identified pathogen. Many cases were refractory to medications and required surgical intervention. Aging, delayed treatment and a large lesion were predictors for poor outcomes.

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.

Treating Fungal Keratitis with Oral Voriconazole Only: A Case Series

BACKGROUND

To report the clinical effect of oral voriconazole only as a treatment for fungal keratitis.

HISTORY AND SIGNS

Three patients (1 female and 2 males) with culture-proven fungal keratitis (1 Mucoraceae, 1 Aspergillus, 1 Fusarium) were included in this study. The patients were treated with oral voriconazole 200 mg twice daily to observe the clinical response in the treatment of fungal keratitis.

THERAPY AND OUTCOME

The mean age of the patients was 51 years and the average treatment duration was 6 weeks. The corneal inflammation in these three patients was eliminated by oral voriconazole only.

CONCLUSIONS

This is the first reported case of oral voriconazole only as a treatment for fungal keratitis. We found that oral voriconazole has a significant clinical effect on the treatment of fungal keratitis.

Pediatric Microbial Keratitis: Experience From Tertiary Referral Centers in New South Wales, Australia

AIMS

The purpose of this study was to report the epidemiology, etiology, microbiologic profile and management of pediatric microbial keratitis in a quaternary and 3 tertiary ophthalmic referral centers across Sydney, New South Wales, Australia.

METHODS

This is a retrospective cohort study of patients ≤ 18 years of age with a clinical diagnosis of microbial keratitis presenting between 1 January 2010 and 31 December 2016 identified from hospital coding and pathology databases. Data were extracted from the medical records. Epidemiology, predisposing factors, referral patterns, microbial profile and treatment outcomes were analyzed.

RESULTS

Eighty eyes from 80 pediatric patients with microbial keratitis were included in the study (10% had bilateral disease). The mean age was 11 ± 5.3 years (range 0-18 years), and 44 were male (55%). Thirty-six percent of patients had ocular and 13.5% systemic comorbidities. The most common risk factor overall was contact lens wear in 26%, trauma (24%), and external lid and eye disease (20%). Overall, 74 organisms were identified, and of those, the most common isolates were Gram-positive organism. Antimicrobial resistance to common antibiotics was low across all isolates. Visual acuity following treatment was worse than 6/60 for 7 patients (11.3%%), 6/15-6/60 for 15 patients (24.2%) and better than 6/12 for 40 patients (64.5%). Preexisting corneal disease and delay of presentation were associated with worse visual prognosis. Serious complications were noted in 16 (21.3%) of patients.

CONCLUSIONS

Contact lens wear, trauma and existing ocular disease remain the most significant risk factors in the pediatric population. Preexisting corneal disease and delay in presentation were associated with poor visual acuity. The majority of patients have a good visual outcome although serious complications are not uncommon and may cause lifelong visual disability.