Diagnostic and Management Strategies of Aspergillus Endophthalmitis: Current Insights

Disorders with Ophthalmic and Thoracic Involvement

A variety of systemic conditions involve the thorax and the eyes. While subtle or nonspecific eye symptoms can be the initial clinical manifestation of some disorders, there can be additional manifestations in the thorax that lead to a specific diagnosis and affect patient outcomes. For instance, the initial clinical manifestation of Sjögren syndrome is dry eye or xerophthalmia; however, the presence of Sjögren lung disease represents a fourfold increase in mortality. Likewise, patients with acute sarcoidosis can initially present with pain and redness of the eye from uveitis in addition to fever and parotitis. Nearly 90% of patients with sarcoidosis have thoracic involvement, and the ophthalmologic symptoms can precede the thoracic symptoms by several years in some cases. Furthermore, a diagnosis made in one system can result in the screening of other organs as well as prompt genetic evaluation and examination of family members, such as in the setting of Marfan syndrome or Ehlers-Danlos syndrome. Multimodality imaging, particularly CT and MRI, plays a vital role in identification and characterization of these conditions. While it is helpful for ophthalmologists to be knowledgeable about these conditions and their associations so that they can order the pertinent radiologic studies, it is also important for radiologists to use the clues from ophthalmologic examination in addition to imaging findings to suggest a specific diagnosis. Systemic conditions with thoracic and ophthalmologic manifestations can be categorized as infectious, inflammatory, autoimmune, neoplastic, or hereditary in origin. The authors describe a spectrum of these conditions based on their underlying cause. ©RSNA, 2024.

Clinical Insights: Antimicrobial Therapy for Infectious Uveitis

Infectious uveitis is a major global cause of vision impairment. Despite the eye's immune privilege, afforded by the blood-ocular barrier that restricts microbial entry, several pathogens such as bacteria, viruses, fungi, and parasites can still infiltrate and cause ocular infections and complications. Clinicians often encounter significant challenges in treating infectious uveitis due to limited or ineffective treatment options. Modern molecular techniques and imaging can aid in diagnosing and assessing intraocular infections. Various antimicrobial therapies exist, spanning topical and systemic treatments, but these are constrained by issues like drug concentration, penetration, effective duration, toxicity, and side effects. Treatment approaches also differ based on the infection's etiology. This review provides recent updates on antimicrobial therapies from a clinical perspective, covering topical, systemic, and regional treatments for infectious uveitis.

Causes of infectious pediatric uveitis: A review

Infectious pediatric uveitis is a rare disease that can cause severe ocular damage if not detected rapidly and treated properly. Additionally, early identification of an infection can protect the child from life-threatening systemic infection. Infectious uveitis can be congenital or acquired and may manifest as a primary ocular infection or as a reactivation. Nevertheless, publications on infectious paediatric uveitis are usually limited to a small number of patients or a case report. So far, most studies on uveitis in children have focused primarily on noninfectious uveitis, and a systematic study on infectious uveitis is lacking. In this review, we summarize the literature on infectious uveitis in pediatric populations and report on the epidemiology, pathophysiology, clinical signs, diagnostic tests, and treatment. We will describe the different possible pathogens causing uveitis in childhood by microbiological group (i.e. parasites, viruses, bacteria, and fungi). We aim to contribute to early diagnosis and management of infectious pediatric uveitis, which in turn might improve not only visual outcome, but also the general health outcome.

Long-term survival following medical management of Aspergillus endocarditis with dissemination as a consequence of steroid therapy in severe COVID-19 pneumonia

A male in his 40's with no known comorbidities developed severe COVID-19 pneumonia and received a four-week course of methylprednisolone. The patient subsequently developed disseminated Aspergillus endocarditis, manifesting as multiple organ involvement including the heart, eyes, and brain. Despite the poor prognosis generally associated with fungal endocarditis, the patient survived following aggressive medical management with a combination of liposomal amphotericin b and voriconazole therapy and is now doing well for over two years and is off antifungal therapy for a year.

Flexosomes as a promising nanoplatform for enhancing tolnaftate ocular delivery: Formulation, in vitro characterization, statistical optimization, ex vivo and microbial in vivo studies

The eye is a complex organ with a unique physiology and anatomy. Using novel nanosystems is expected to enhance ocular drug permeation and retention. Hence, this work aimed to study the potential of flexosomes as an ocular delivery system to enhance the corneal permeation and antifungal activity of Tolnaftate (TOL). Different flexosomes formulae were formulated using ethanol injection method, employing a 31.22 full factorial design. The studied formulation variables were: X1: amount of stearyl amine, X2: hydration volume and X3: type of edge activator. Encapsulation efficiency, particle size and zeta potential were selected as dependent variables. FX5 was selected as the optimal TOL flexosomes and showed encapsulation efficiency of 66.08 ± 11.38%, particle size of 154.99 ± 29.11 nm and zeta potential of 42.95 ± 0.64 mV. FX5 was subjected to further ex vivo and in vivo studies which showed that TOL flux was significantly increased through FX5 compared to TOL suspension. Draize test and histopatholoigal tests assured that FX5 is safe to be used for eye.. The in vivo fungal susceptibility testing using Aspergillus niger demonstrated the superior and more durable antifungal activity of FX5 than TOL suspension. Hence, FX5 can be considered as promising nanocarrier for safe and efficient ocular TOL delivery.

Fungal Endophthalmitis Secondary to Aspergillus terreus Exacerbated by Intravitreal Dexamethasone in a Patient With Sarcoidosis

Purpose: To report a case of Aspergillus terreus endophthalmitis associated with systemic immunosuppression and an intraocular steroid implant in a patient with sarcoidosis. Methods: A case report was evaluated and a literature review performed. Results: A patient with a history of pulmonary and ocular sarcoidosis presented with new-onset uveitis and was treated for presumed sarcoid flare with oral prednisone and an intravitreal dexamethasone implant before developing worsening vision. She was ultimately diagnosed with A terreus endophthalmitis. Despite both systemic and local antifungals, the visual acuity at the most recent follow-up was no light perception without pain or active inflammation. No definitive source of the fungal disease had been identified. Conclusions: Endophthalmitis resulting from A terreus is associated with poor outcomes. Given the ability of fungal endophthalmitis to mimic other causes of uveitis, one must maintain a high suspicion in patients with any degree of immunosuppression.

Endogenous Endophthalmitis - A Major Review

Endogenous endophthalmitis (EE) is an uncommon but potentially devastating ocular infection involving the inner layers of the eye. The global incidence of EE is on the rise. Common ocular signs and symptoms associated with EE include conjunctival injection, ocular pain, and reduced visual acuity. On clinical examination, a history of prior or coexisting systemic infections, symptoms (e.g., fever, malaise), and localizing features may be noted. Clinical diagnosis is often challenging, resulting in critical delays that contribute to a poor prognosis. Blood cultures and ocular fluid samples can aid in conforming causative pathogen(s), after which empirical antibiotic therapy, both systemic and intravitreal, should be instated. The use of steroids to suppress inflammation remains controversial. Surgical options include pars plana vitrectomy. Overall prognosis varies depending on host and pathogen factors, and early diagnosis and initiation of appropriate treatment are crucial.

Non-Pathogenic Aspergillus oryzae Acute Exogenous Endophthalmitis after Penetrating Keratoplasty: The First Case Report in the Literature

The authors report a singular case of post-operative exogenous fungal endophthalmitis caused by a non-pathogenic fungal agent: Aspergillus oryzae. A 75-year-old Caucasian woman with post-penetrating keratoplasty fungal endophthalmitis due to a nonpathogenic A. oryzae, resistant to the current azoles anti-fungal agents, was treated with subtotal vitrectomy, intravitreal injection, and systemic voriconazole therapy. Complete resolution of the endophthalmitis occurred after two subsequent intravitreal injections and a 2-month-long systemic delivery of voriconazole. The quick identification of the fungal agent allowed immediate and targeted therapy. In the article, the safety and efficacy of both systemic and intravitreal voriconazole treatments are discussed.

Implementing polymeric pseudorotaxanes for boosting corneal permeability and antiaspergillus activity of tolnaftate: formulation development, statistical optimization, ex vivo permeation and in vivo assessment

Fungal keratitis (FK) is a devastating ocular disease that can cause corneal opacity and blindness if not treated effectively. Tolnaftate (TOL) is a selective fungicidal drug against Aspergillus spp. which are among the most common causes of mycotic keratitis. TOL is lipophilic drug with low water solubility and permeation which act as obstacles for its clinical ocular efficacy. Hence, this study aimed to statistically optimize a novel polymeric pseudorotaxanes (PSRs) containing TOL for enhancing its ocular permeability and antifungal effect. For achieving this goal, a full 3¹.2² factorial design was fashioned for preparing and optimizing TOL-PSRs using film hydration technique. Three formulation variables were studied: drug amount (X₁), weight ratio of Pluronics to HPβCD (X₂) and Pluronic system (X₃). Entrapment efficiency percent (EE%) (Y₁), particle size (PS) (Y₂) and zeta potential (ZP) (Y₃) were set as dependent variables. The selected optimal TOL-PSRs (PSR1) showed EE% of 71.55 ± 2.90%, PS of 237.05 ± 12.80 nm and ZP of −32.65 ± 0.92 mV. In addition, PSR1 was compared to conventional polymeric mixed micelles (PMMs) and both carriers significantly increased the drug flux and resulted in higher amount permeated per unit area in 8 h compared to drug suspension. The histopathological studies assured the safety of PSR1 for ocular use. The in vivo susceptibility testing using Aspergillus niger confirmed that PSR1 displayed sustained antifungal activity up to 24 h. The obtained results revealed the admirable potential of PSR1 to be used as novel nanocarriers for promoting TOL ocular delivery.

Proteomic profiling of aspergillus flavus endophthalmitis derived extracellular vesicles in an in-vivo murine model

Extracellular Vesicles (EVs) play pivotal roles in cell-to-cell communication, and are involved in potential pathological and physiological cellular processes. The aim of this study was to understand the proteomic cargo of these vesicles, in a murine model of Aspergillus flavus (AF) endophthalmitis. EVs were isolated from A. flavus infected C57BL/6 mice eyes by differential ultracentrifugation at 24 h post infection (p.i) and isolated EVs were characterized by Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM), Exocet assay, and western blot. Proteomic profiling of EVs was then evaluated by mass spectrometry (LC-MS/MS) and compared it with control uninfected mice. The average size of the EVs were 180-280 nm by DLS and the number of EVs increased to 1.55 × 1010 in infected mice in comparison to EVs from uninfected eye (1.24 × 109). Western blot was positive for CD9, CD63, and CD81 confirming the presence of EVs. LC-MS/MS analysis, identified 81 differentially expressed proteins, of these 22 were up-regulated and 59 were down-regulated. Gene Ontology (GO) analysis revealed enrichment of lipid metabolism, protein complex binding, and transferase activity, and the proteins associated were Aquaporin-5, CD177 antigen, Solute carrier family-25, and Calcium/calmodulin-dependent protein kinase. Additionally, KEGG pathway analysis indicated that glucagon signalling, metabolic, and PPAR signalling pathway were significantly associated with EVs from A. flavus infected mice eyes. The protein cargo in EVs from A. flavus endophthalmitis provides new insights into the pathogenesis of fungal endophthalmitis and validation of these proteins can serve as diagnostic and/or prognostic biomarkers for patients with a clinical suspicion of fungal endophthalmitis.

LAY SUMMARY

EVs play an important role in cell communication. In our study proteomic profiling of EVs isolated from A. flavus infected mice provided new insights into the understanding of the pathobiology of A. flavus endophthalmitis and validation of these proteins can serve as biomarkers.

Enhanced Ocular Anti-Aspergillus Activity of Tolnaftate Employing Novel Cosolvent-Modified Spanlastics: Formulation, Statistical Optimization, Kill Kinetics, Ex Vivo Trans-Corneal Permeation, In Vivo Histopathological and Susceptibility Study

Tolnaftate (TOL) is a thiocarbamate fungicidal drug used topically in the form of creams and ointments. No ocular formulations of TOL are available for fungal keratitis (FK) treatment due to its poor water solubility and unique ocular barriers. Therefore, this study aimed at developing novel modified spanlastics by modulating spanlastics composition using different glycols for enhancing TOL ocular delivery. To achieve this goal, TOL basic spanlastics were prepared by ethanol injection method using a full 3² factorial design. By applying the desirability function, the optimal formula (BS6) was selected and used as a nucleus for preparing and optimizing TOL-cosolvent spanlastics according to the full 3¹.2¹ factorial design. The optimal formula (MS6) was prepared using 30% propylene glycol and showed entrapment efficiency percent (EE%) of 66.10 ± 0.57%, particle size (PS) of 231.20 ± 0.141 nm, and zeta potential (ZP) of -32.15 ± 0.07 mV. MS6 was compared to BS6 and both nanovesicles significantly increased the corneal permeation potential of TOL than drug suspension. Additionally, in vivo histopathological experiment was accomplished and confirmed the tolerability of MS6 for ocular use. The fungal susceptibility testing using Aspergillus niger confirmed that MS6 displayed more durable growth inhibition than drug suspension. Therefore, MS6 can be a promising option for enhanced TOL ocular delivery.

Aspergillus Endophthalmitis: Epidemiology, Pathobiology, and Current Treatments

Fungal endophthalmitis is one of the leading causes of vision loss worldwide. Post-operative and traumatic injuries are major contributing factors resulting in ocular fungal infections in healthy and, more importantly, immunocompromised individuals. Among the fungal pathogens, the Aspergillus species, Aspergillus fumigatus, continues to be more prevalent in fungal endophthalmitis patients. However, due to overlapping clinical symptoms with other endophthalmitis etiology, fungal endophthalmitis pose a challenge in its diagnosis and treatment. Hence, it is critical to understand its pathobiology to develop and deploy proper therapeutic interventions for combating Aspergillus infections. This review highlights the different modes of Aspergillus transmission and the host immune response during endophthalmitis. Additionally, we discuss recent advancements in the diagnosis of fungal endophthalmitis. Finally, we comprehensively summarize various antifungal regimens and surgical options for the treatment of Aspergillus endophthalmitis.

The Diagnosis and Treatment of Fungal Endophthalmitis: An Update

In recent, large case series of fungal endophthalmitis (FE) that were published by Asian authors, the most frequent etiologic agents for all types of FE are molds (usually Aspergillus species, while Fusarium is the prevalent etiology in keratitis-related FE). Candida was the organism found in most cases of endogenous FE. However, we must keep in mind that prevalence of fungal species varies with the geographical area. Lately, polymerase chain reaction (PCR) was increasingly used for the diagnosis of FE, allowing for very high diagnostic sensitivity, while the costs become more affordable with time. The most important shortcoming of PCR—the limited number of pathogens that can be simultaneously searched for—may be overcome by newer techniques, such as next-generation sequencing. There are even hopes of searching for genetic sequences that codify resistance to antifungals. We must not forget the potential of simpler tests (such as galactomannan and β-d-glucan) in orienting towards a diagnosis of FE. There are few reports about the use of newer antifungals in FE. Echinocandins have low penetration in the vitreous cavity, and may be of use in cases of fungal chorioretinitis (without vitritis), or injected intravitreally as an off-label, salvage therapy.

Fungal Endophthalmitis: A Comprehensive Review

Endophthalmitis is a serious ophthalmologic condition involving purulent inflammation of the intraocular spaces. The underlying etiology of infectious endophthalmitis is typically bacterial or fungal. The mechanism of entry into the eye is either exogenous, involving seeding of an infectious source from outside the eye (e.g., trauma or surgical complications), or endogenous, involving transit of an infectious source to the eye via the bloodstream. The most common organism for fungal endophthalmitis is Candida albicans. The most common clinical manifestation of fungal endophthalmitis is vision loss, but other signs of inflammation and infection are frequently present. Fungal endophthalmitis is a clinical diagnosis, which can be supported by vitreous, aqueous, or blood cultures. Treatment involves systemic and intravitreal antifungal medications as well as possible pars plana vitrectomy. In this review, we examine these essential elements of understanding fungal endophthalmitis as a clinically relevant entity, which threatens patients’ vision.

A 10-year-old immunocompetent girl with endogenous fungal endophthalmitis: Report of a case and review of the literature

Endogenous Endophthalmitis (EE) is a rare cause of blindness in the pediatric age group and this may account for the paucity of management guidelines in the literature. In this report, we describe our experience with a 10-year-old immunocompetent female who developed EE and became blind because of rapidly progressive and destructive inflammatory changes in her eye in spite of seemingly timely treatment.

Differential inflammatory response to Aspergillus flavus and Candida albicans infection in human retinal pigment epithelial cells: Role in treatment of endophthalmitis

OBJECTIVE

Fungal endophthalmitis is an emerging vision-threatening complication in tropical countries and the Retinal pigment epithelial cells (RPE) are said to play a major role in the retinal pathology. The aim of this study was to compare the immune response of Retinal pigment epithelial cells (RPE) challenged with A. flavus and C. albicans strains, isolated from patients with fungal endophthalmitis.

MATERIAL AND METHODS

Retinal Pigment epithelial cells (ARPE-19) cells were infected with A. flavus and C. albicans, and gene expression were assessed for TLRs, immune-mediators, and matrix metalloproteinases (MMPs).

RESULTS

We observed a time-dependent gene expression of TLRs (TLR-2,-7 and -9); IL-8 and TNF-α in RPE cells challenged with A. flavus and C. albicans. Additonally, IL-6 (3.3 fold), IL-10 (15.2 fold), and IL-17 (5.6 fold) were significantly up-regulated only in cells infected with A. flavus. Additionally, MMP-9 gene expression was up-regulated in both A.flavus as well as C.albicans infected cells, while MMP- 2 gene expression was induced only in cells infected with C.albicans. A total of 9 upregulated differential expression of genes (DEGs) in A. flavus infected cells and 7 DEGs in C. albicans infected cells were used to construct Protein-protein interaction (PPI) network.

CONCLUSION

RPE cells induced a differential innate immune response depending on fungal species involved (A.flavus and C.albicans) and may provide clues for novel treatment targets and better prognosis.

Exogenous Fungal Endophthalmitis: Clues to Aspergillus Aetiology with a Pharmacological Perspective

Exogenous fungal endophthalmitis (EXFE) represents a rare complication after penetrating ocular trauma of previously unresolved keratitis or iatrogenic infections, following intraocular surgery such as cataract surgery. The usual latency period between intraocular inoculation and presentation of symptoms from fungal endophthalmitis is several weeks to months as delayed-onset endophthalmitis. Aspergillus spp., is the most common causative mould pathogen implicated in this ocular infection and early diagnosis and prompt antimicrobial treatment, concomitantly in most cases with expert surgical attention, reduce unfavorable complications and increase the possibility of eye function preservation. Topical, intravitreal and systemic antifungal molecules are the mainstay of a medical approach to the disease and azoles, polyenes and in particular cases echinocandins are the pharmacological classes most commonly used in clinical practice. This review discusses pharmacokinetics and pharmacodynamic of antifungal agents in their principal modes of administration with a focus on their ability to achieve high drug concentration in the vitreous and ocular tissues.