Fungal and parasitic infections of the eye

Pathobiology of Fungal Endophthalmitis: A Major Review

Fungal endophthalmitis is a chronic inflammatory condition of the eye's posterior segment that can lead to irreversible vision loss. While relatively rare in western countries, its incidence is notably higher in Asia, particularly India. The condition's prevalence is exacerbated by factors such as intravenous drug use, antibiotics, and ocular surgeries. Fungal endophthalmitis can be categorized as endogenous, arising from systemic infection, or exogenous, linked to external sources such as trauma or surgery. The fungal agents responsible vary by region, with Candida species common in the West and Aspergillus and Fusarium species more prevalent in India. Management typically involves vitrectomy and intravitreal antifungal drugs such as amphotericin B and voriconazole, though treatment is often complicated by multidrug resistance and culture-negative cases. Recent proteomic and transcriptomic analyses have highlighted the early and sustained activation of the host immune response during infection involving key inflammatory and oxidative stress-related proteins. Given the potential for excessive inflammation to cause retinal damage, targeted immunotherapies are crucial. Immunomodulation, which aims to balance the immune response, shows promise in preserving vision while effectively combating the infection. Key targets for immunomodulation include pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-17), chemokines (CCL2, CXCL8), Toll-like receptors (TLR2, TLR4), and the complement system. Additionally, modulating the activity of macrophages, neutrophils, regulatory T cells, and Th17 cells, as well as targeting inflammasomes, can help control inflammation. Biologic agents and small molecule inhibitors offer further avenues for precise immune response modulation. This review underscores the importance of a comprehensive understanding of host-pathogen interactions in the development of effective therapies for fungal endophthalmitis.

Social determinants of health as drivers of fungal disease

Disparities in social determinants of health (SDOH) play a significant role in causing health inequities globally. The physical environment, including housing and workplace environment, can increase the prevalence and spread of fungal infections. A number of professions are associated with increased fungal infection risk and are associated with low pay, which may be linked to crowded and sub-optimal living conditions, exposure to fungal organisms, lack of access to quality health care, and risk for fungal infection. Those involved and displaced from areas of armed conflict have an increased risk of invasive fungal infections. Lastly, a number of fungal plant pathogens already threaten food security, which will become more problematic with global climate change. Taken together, disparities in SDOH are associated with increased risk for contracting fungal infections. More emphasis needs to be placed on systematic approaches to better understand the impact and reducing the health inequities associated with these disparities.

Eye fungal infections: a mini review

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

Therapeutic Ultrasound-Enhanced Transcorneal PHMB Delivery In Vitro

OBJECTIVE

Delivery of therapeutic agents to the cornea is a difficult task in the treatment of parasitic keratitis. In this study, we looked at using different combinations of ultrasound parameters to enhance corneal permeability to polyhexamethylene biguanide (PHMB), a clinically available ophthalmic antiparasitic formulation.

METHODS

Permeability of PHMB was investigated in vitro using a standard diffusion cell setup. Continuous or 25% duty-cycle ultrasound was used at frequencies of 400 or 600 kHz, intensities of 0.5 or 0.8 W/cm² , and exposure times ranging from 1 to 5 minutes. Structural changes in the cornea were examined using light microscopy.

RESULTS

Ultrasound exposure produced increases in transcorneal delivery in every treatment parameter combination when compared to the sham treatment. The highest increase was 2.36 times for 5 minutes of continuous ultrasound at a frequency of 600 kHz and an intensity of 0.5 W/cm² with statistical significance (p <.001). Histological analysis showed that ultrasound application only caused structural changes in the corneal epithelium, with most damage being at the surface layers.

CONCLUSIONS

This study suggests the possibility of therapeutic ultrasound as a novel drug delivery technique for the treatment of parasitic keratitis. Further studies are needed to examine the thermal effects of these proposed ultrasound applications and the long-term viability of this treatment.

Scedosporium apiospermum contact lens-related keratitis: a case report and literature review

Background

Scedosporium apiospermum (SA) is commonly present in temperate climates. It can induce cutaneous and subcutaneous tissue infections as well as disseminated infections in immunocompromised or immunocompetent hosts. The eye is rarely involved. Keratomycosis is usually caused by plant-related injuries. Here, we describe a patient with a severe and sight-threatening corneal abscess caused by SA, which was associated with contact lens wear and was successfully treated with a combination of surgical and medical therapies.

Case Presentation

An otherwise healthy 22-year-old woman, with history of contact lens wearing, was referred to the Ophthalmic Department of Bari University, Bari, Italy for evaluation of a corneal abscess and hypopyon in her left eye. Intensive topical and systemic antibiotic therapy was initiated after obtaining con- junctival swabs. Within 2 days, her ophthalmic condition had worsened, and her best-corrected visual acuity (BCVA) dropped to counting fingers. She underwent penetrating keratoplasty, after which her ophthalmic condition improved. Microbiological culture, obtained from the explanted cornea, revealed SA infection. This was addressed with specific topical and systemic therapy using voriconazole. Two weeks later, the con- dition of her left eye was stable, with mild corneal edema and no sign of acute graft rejection. Her BCVA improved to 20/25, and all medications were discontinued, except for the steroid eye drop. The patient was scheduled for a 1-month follow-up.

Conclusions

Prompt identification of the etiological agent is mandatory to perform appropriate therapy in cases of keratomycosis. Surgery to remove the infected cornea is helpful in patients with deteriorating condition, in whom the initial medical therapy has failed. Topical and systemic antimycotic therapy, based on microbiological culture, is recommended as an adjunctive therapy for the surgical management of severe corneal mycotic abscesses.

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.

Post-Traumatic Endophthalmitis: Clinico-Microbiological Profile, Antimicrobial Susceptibility and Prognostic Factors at a Tertiary Eye Care Centre in Eastern India

Purpose: To analyse clinico-microbiological profile, antimicrobial susceptibilities, and visual prognostic factors in post-traumatic endophthalmitis (PTE).Methods: Retrospective clinico-microbiological data analysis for five years (2014-18). Prognostic factors for visual outcomes were analysed by multivariate logistic regression analysis.Results: Four hundred and eighteen patients with clinically diagnosed PTE were analysed. Culture positivity was found in 46.7% samples (44.5% vitreous, 83.3% non-vitreous). Pathogens isolated were Gram positive cocci (GPC, 49.3%, good susceptibility to vancomycin/cefazolin), Gram negative bacilli (GNB, 28.1%, <90% susceptibility to all antibiotics and 25.8% multidrug resistance), Gram positive bacilli (13.1%) and fungi (9.5%). Poor visual prognosis was associated with culture positivity, fungal or polymicrobial PTE, poor view of fundus and presence of membranes on ultrasound scans.Conclusion: GPC and GNB are the predominant pathogens in PTE, with GNB most commonly multidrug resistant. Culture positivity, polymicrobial and fungal PTE, poor view of fundus and vitreous membranes are markers of poor visual outcome.

Recent advances on mycotic keratitis caused by dematiaceous hyphomycetes

Dematiaceous hyphomycetes (DH) are darkly pigmented fungi ubiquitously found all over the world as plant pathogens and saprophytes, and many of the members of this group have emerged as opportunistic pathogens. These fungi are responsible for a wide variety of infections including mycotic keratitis, which is considered as one of the major causes of corneal blindness, particularly in tropical and subtropical countries with an annual global burden of about 1 000 000 patients. The infection is more common in workers working in an outdoor environment. Moreover, trauma is found to be the most important predisposing cause of mycotic keratitis. Considerable delay in diagnosis and scarcity of effective pharmacological drugs are the major factors responsible for increased morbidity and visual impairment. Considering the crucial role of DH in mycotic keratitis, in the present review, we have focused on major DH with special emphasis on their pathogenicity, diagnosis and treatment strategies.

Identification and antimicrobial susceptibility of microorganisms isolated from severe corneal ulcers of dogs in Thailand

This study aims to determine the microbiological profile and risk factors associated with antimicrobial-resistant bacteria in canine severe corneal ulcers. Thirty-two corneal and conjunctival swabs were collected from dogs with diagnosed severe corneal ulcers that presented to Prasu-Arthorn veterinary teaching hospital in Nakhon Pathom, Thailand from June 2015 to June 2016. Microorganisms were identified by means of genotypic and phenotypic approaches. Of 32 ulcers sampled, 26 (81.3%) yielded culturable microorganisms with 24 bacterial isolates and 7 fungal isolates. The most commonly isolated bacteria were Staphylococcus spp. (45.8%, 11/24) and Pseudomonas aeruginosa (20.8%, 5/24). Out of 11 staphylococcal isolates identified, 10 carried the mecA gene providing methicillin resistance. The extended-spectrum β-lactamase (ESBL) encoding genes blaCTX-M and blaVEB-1 were found in an Acinetobacter lwoffii isolate, and blaSHV was found in a P. aeruginosa isolate. Based on the Clinical Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoint criteria, minimum inhibitory concentrations values showed that all bacteria, except for staphylococci, were susceptible to current ophthalmic antibiotics. More than 50% of staphylococci were resistant to all generations of fluoroquinolones and fusidic acid. Chloramphenicol was highly active against staphylococci (81.3% susceptible). The width (P=0.02) and the depth (P=0.04) of ulcers predicted greater risk of yielding resistant bacteria. The identification of antimicrobial-resistant bacteria prompts practitioners to be prudent when choosing ophthalmic antibiotics for severe corneal ulcers.

A new worm infiltrating the human cornea: A report of three cases

Purpose

To characterize a new species of parasitic nematode that triggers uveitis.

Observations

Three previously healthy, relatively young people each contracted a corneal stromal nematode that, upon surgical removal and examination, did not match any known nematodes. Clinical ocular findings included corneal opacification, visible corneal worms, conjunctival injection, and uveitis.

Conclusions and Importance

The three cases presented here represent a previously undescribed parasitic infection of the cornea by an unidentified nematode. These findings may represent a previously unrecognized zoonotic infection from wildlife sources and potentially a newly documented nematode requiring description. Future clinical findings regarding this newly described nematode are needed to further develop our understanding of the disease.

Effects of Lycium barbarum (goji berry) on dry eye disease in rats

Lycium barbarum (goji berry) has long been used as a food and traditional herbal medicine. This study aimed to investigate the beneficial effect of the goji berry on dry eye disease in rats. Male Sprague-Dawley rats with induced dry eye disease were randomly assigned to four groups: Vehicle (control), low-dose goji berry extract [GBE; 250 mg/kg/body weight (bw)], median-dose GBE (350 mg/kg/bw), and high-dose GBE (500 mg/kg/bw). Three methods, Schirmer's test, tear break-up time (BUT) measurement and keratoconjunctival fluorescein staining, were used to evaluate the effect of GBE on symptoms of dry eye disease experienced by the rats. The results of the present study revealed that both the Schirmer's test score and tear BUT significantly increased following 1 week of GBE administration. Furthermore, the severity of the keratoconjunctival staining decreased significantly. In addition, the results suggested that administration of GBE may ameliorate dry eye disease symptoms in a dose-dependent manner. There were no mortalities and no apparent abnormal histopathology changes in the liver or kidney tissues of rats administered GBE for 21 consecutive days. Polysaccharides and betaine present in GBE may have important effects in alleviating dry eye disease induced by oxidative stress and inflammation. In conclusion, the goji berry is a safe, functional food with beneficial effects in alleviating dry eye disease.

Microbiota and Particulate Matter Assessment in Portuguese Optical Shops Providing Contact Lens Services

The aim of this work was to assess the microbiota (fungi and bacteria) and particulate matter in optical shops, contributing to a specific protocol to ensure a proper assessment. Air samples were collected through an impaction method. Surface and equipment swab samples were also collected side-by-side. Measurements of particulate matter were performed using portable direct-reading equipment. A walkthrough survey and checklist was also applied in each shop. Regarding air sampling, eight of the 13 shops analysed were above the legal requirement and 10 from the 26 surfaces samples were overloaded. In three out of the 13 shops fungal contamination in the analysed equipment was not detected. The bacteria air load was above the threshold in one of the 13 analysed shops. However, bacterial counts were detected in all sampled equipment. Fungi and bacteria air load suggested to be influencing all of the other surface and equipment samples. These results reinforce the need to improve air quality, not only to comply with the legal requirements, but also to ensure proper hygienic conditions. Public health intervention is needed to assure the quality and safety of the rooms and equipment in optical shops that perform health interventions in patients.

Ocular Emergencies: Red Eye

"Red eye" is used as a general term to describe irritated or bloodshot eyes. It is a recognizable sign of an acute/chronic, localized/systemic underlying inflammatory condition. Conjunctival injection is most commonly caused by dryness, allergy, visual fatigue, contact lens overwear, and local infections. In some instances, red eye can represent a true ocular emergency that should be treated by an ophthalmologist. A comprehensive assessment of red eye conditions is required to preserve the patients visual function. Severe ocular pain, significant photophobia, decreased vision, and history of ocular trauma are warning signs demanding immediate ophthalmological consultation.

Endophthalmitis associated with Purpureocillium lilacinum during infliximab treatment for surgically induced necrotizing scleritis, successfully treated with 27-gauge vitrectomy

PURPOSE

To report a case of endophthalmitis associated with Purpureocillium lilacinum (P. lilacinum) during infliximab treatment for surgically induced necrotizing scleritis, successfully treated with 27-gauge vitrectomy.

METHODS

A single case report.

RESULTS

A 71-year-old man who had undergone immunosuppressive therapy, including infliximab, for surgically induced necrotizing scleritis (SINS) in his left eye complained of visual disturbance and eye pain in the eye. He had a past history of surgery for recurrent pterygium: pterygium excision, amnion transplantation with mitomycin C and limbal transplantation. Visual acuity in the left eye was counting fingers at 30 cm, and intraocular pressure was 3.0 mmHg. Slit-lamp examination revealed the presence of anterior chamber cells (3+), and a B-mode ultrasound scan showed a vitreous opacity. We made a diagnosis of endophthalmitis and performed 27-gauge microincision vitrectomy surgery (27GMIVS) with antibiotic perfusion of ceftazidime, vancomycin and voriconazole. Intraoperative findings included a fungus-like ball-shaped opacity in the vitreous, and a close-to-normal retinal appearance. A vitreous body culture identified the presence of P. lilacinum. After 2 months of antibacterial and antifungal therapy, inflammation decreased and visual acuity recovered to 20/100.

CONCLUSIONS

This is the first report of a case of endophthalmitis associated with P. lilacinum during infliximab treatment for SINS. Scleral thinning due to necrotizing scleritis, especially during immunosuppressive therapy, is a risk factor for endophthalmitis. We found that 27GMIVS was a useful strategy for such a challenging clinical situation.

Killing of diverse eye pathogens (Acanthamoeba spp., Fusarium solani, and Chlamydia trachomatis) with alcohols

Background

Blindness is caused by eye pathogens that include a free-living protist (Acanthamoeba castellanii, A. byersi, and/or other Acanthamoeba spp.), a fungus (Fusarium solani), and a bacterium (Chlamydia trachomatis). Hand-eye contact is likely a contributor to the spread of these pathogens, and so hand washing with soap and water or alcohol–based hand sanitizers (when water is not available) might reduce their transmission. Recently we showed that ethanol and isopropanol in concentrations present in hand sanitizers kill walled cysts of Giardia and Entamoeba, causes of diarrhea and dysentery, respectively. The goal here was to determine whether these alcohols might kill infectious forms of representative eye pathogens (trophozoites and cysts of Acanthamoeba, conidia of F. solani, or elementary bodies of C. trachomatis).

Methodology/Principal findings

We found that treatment with 63% ethanol or 63% isopropanol kills >99% of Acanthamoeba trophozoites after 30 sec exposure, as shown by labeling with propidium iodide (PI) and failure to grow in culture. In contrast, Acanthamoeba cysts, which contain cellulose fibers in their wall, are relatively more resistant to these alcohols, particularly isopropanol. Depending upon the strain tested, 80 to 99% of Acanthamoeba cysts were killed by 63% ethanol after 2 min and 95 to 99% were killed by 80% ethanol after 30 sec, as shown by PI labeling and reduced rates of excystation in vitro. Both ethanol and isopropanol (63% for 30 sec) kill >99% of F. solani conidia, which have a wall of chitin and glucan fibrils, as demonstrated by PI labeling and colony counts on nutrient agar plates. Both ethanol and isopropanol (63% for 60 sec) inactivate 96 to 99% of elementary bodies of C. trachomatis, which have a wall of lipopolysaccharide but lack peptidoglycan, as measured by quantitative cultures to calculate inclusion forming units.

Conclusions/Significance

In summary, alcohols kill infectious forms of Acanthamoeba, F. solani, and C. trachomatis, although longer times and higher ethanol concentrations are necessary for Acanthamoeba cysts. These results suggest the possibility that expanded use of alcohol-based hand sanitizers in places where water is not easily available might reduce transmission of these important causes of blindness.

Hand washing with soap and water is an important public health tool for reducing transmission of viruses, bacteria, fungi, and protists. Alcohol-based hand sanitizers, which are widely dispensed in hospitals and public places, kill many of these same pathogens. What is not known is how effectively the alcohol-based hand sanitizers kill protists, fungi, or bacteria that cause eye disease. Here we show ethanol and isopropanol penetrate the walls and kill a free-living protist (Acanthamoeba castellanii, A. byersi, and other Acanthamoeba spp.), and a fungus (Fusarium solani), each of which causes keratitis, as well as a bacterium (Chlamydia trachomatis) that causes trachoma. These results suggest the possible benefit of hand sanitizers in the prevention of these eye pathogens.

A rare case of isolated cysticercus involvement of inferior rectus muscle presenting with upward gaze restriction

Cysticercosis is a parasitic infection caused by larvae known as cysticercus cellulosae. Orbital cysticercosis is usually a part of generalised systemic infestation. Isolated infection of the extra-occular muscle is an extremely rare entity. Involvement of orbital adnexas are rare even if associated with brain infection. Here, we report a case of an 18-year-old boy who presented with eccentric proptosis and restriction in upward gaze and was diagnosed with cysticercosis of inferior rectus.

The first case of fungal endophthalmitis caused by Emericella nidulans after cataract surgery

Emericella nidulans is a species that has only rarely been implicated in human disease after cataract surgery. Here, we report the first postoperative case in the literature, as far as we know. The patient was a 50-year-old patient presented with mild anterior uveitis one week after cataract surgery, and hypopion developed over the next two days. First microbiological evaluation and the results of direct microscopy and cultures of the anterior chamber and vitreous samples were found to be negative. Despite vigorous topical and intravitreal (vancomycin and amikacin) therapy, the endophthalmitis did not improve. Anterior chamber paracentesis, vitreous tap and finally complete vitrectomy with removal of the capsular bag including the intraocular lens (IOL) were performed. The anterior chamber, vitreous fluid samples and IOL were submitted to the microbiology laboratory: the culture yielded E. nidulans growth. Ocular inflammation resolved and vision improved on intravenous, subconjunctival and long-term oral voriconazole treatment. E. nidulans can be an important cause of ocular fungal infections including endophthalmitis, and voriconazole seems to be effective for the treatment of E. nidulans endophthalmitis.

Endogenous mycotic endophthalmitis in a dog with candiduria and Evans syndrome

This report describes the clinical presentation, diagnosis, histologic lesions, and outcome of endogenous mycotic endophthalmitis secondary to candiduria in a three-year-old female spayed Dachshund. The dog was being treated for Evans syndrome for one month prior to being diagnosed with candiduria and fibrinous uveitis OS. The left eye was enucleated due to secondary glaucoma, and the fungal urinary tract infection was treated successfully. Uveitis developed in the contralateral eye with relapse of the urinary tract infection in the following weeks. The right eye was medically managed until secondary glaucoma developed and was subsequently enucleated. Histopathology of both eyes showed evidence of endophthalmitis with intralesional fungal organisms, consistent with Candida spp. Ocular candidiasis is rare in dogs. To the authors' knowledge, this is the first report of endogenous mycotic endophthalmitis with concurrent candiduria in a dog.

Ocular pathological changes in hamsters experimentally infected with Schistosoma mansoni

Ocular lesions have been reported in patients with schistosomiasis; however, the problem with studying schistosomal infection of the human eye is that biopsies are almost impossible to take, and histopathological examination of suspicious lesions can only be undertaken post-mortem or after enucleation. This work aimed to study the possible effects and pathogenesis of schistosomiasis on the eye. This study involved 55 hamsters; five hamsters remained non-infected and the remaining 50 hamsters were infected with Schistosoma mansoni cercariae. Infected hamsters were sacrificed on weeks 8, 12, 16 and 20 post-infection (pi). Eye sections were prepared and stained for histopathological and immunohistochemical studies. Histopathological changes detected in hamsters infected after 16 and 20 weeks included looseness and oedema of the innermost retinal layers together with hyperplastic polypoid growth. Neither eggs nor granulomata were detected in eye sections throughout the experimental period. Deposition of S. mansoni antigen was revealed in 35% of infected hamsters. Later, on weeks 16 and 20 pi, moderate subepithelial conjuctival deposits and marked subchoroidal and scleral deposition were detected. In conclusion, the deposition of schistosomal antigen and immune complexes may play a pivotal role in the ocular changes that occur in schistosomiasis, even in the absence of detectable Schistosoma eggs. Schistosomiasis should be suspected in cases with unexplained ophthalmological findings, especially in endemic areas.

Contact lens associated microbial keratitis: practical considerations for the optometrist

Microbial keratitis (MK) is a corneal condition that encompasses several different pathogens and etiologies. While contact lens associated MK is most often associated with bacterial infections, other pathogens (fungi, Acanthamoeba species, etc) may be responsible. This review summarizes the risk factors, microbiology, diagnostic characteristics, and treatment options for all forms of contact lens-related MK.

A retrospective analysis of eleven cases of invasive rhino-orbito-cerebral mucormycosis presented with orbital apex syndrome initially

Background

Rhino-orbito-cerebral mucormycosis(ROCM) is an invasive fungal infection that usually occurs in immunocompromised patients and sometimes presents as orbital apex syndrome(OAS) initially. It is rapidly fatal without an early diagnosis and treatment. We report the cases of invasive ROCM presenting with OAS initially in order to raise the attention of clinicians.

Methods

We retrospectively investigated eleven cases of invasive ROCM presenting initially with OAS admitted between January 2006 and December 2013. We analyzed clinical features, results of laboratory and radiological examinations, nasal endoscopy, aggressive surgical excision and debridement, and medical management outcomes of each case.

Results

A total of eleven cases of invasive ROCM with OAS as an initial sign were presented. Mucormycosis was accompanied by type II diabetes mellitus in nine cases, renal transplant in one case, and injury caused by traffic accident in one case. Anterior rhinoscopy revealed palatine or nasal necrotic lesions in all patients, and transethmoidal optic nerve decompression was carried out in three patients at the same time. CT scan revealed rhino-orbital-cerebral involvement in every patient. All patients were given intravenous amphotericin B. Nine patients underwent surgical debridement of necrotic tissue. Three patients survived.

Conclusions

ROCM is a severe, emergent and fatal infection requiring multidisciplinary management. It may often present with OAS initially. For ophthalmologist, mucormycosis must be considered in immunocompromised patients presenting with OAS initially, and anterior rhinoscopy is imperative before hormonotherapy, even in the cases absent of ketoacidosis induced by diabetes mellitus.

An efficient intelligent analysis system for confocal corneal endothelium images

A confocal microscope provides a sequence of images of the corneal layers and structures at different depths from which medical clinicians can extract clinical information on the state of health of the patient's cornea. A hybrid model based on snake and particle swarm optimisation (S-PSO) is proposed in this paper to analyse the confocal endothelium images. The proposed system is able to pre-process images (including quality enhancement and noise reduction), detect cells, measure cell densities and identify abnormalities in the analysed data sets. Three normal corneal data sets acquired using a confocal microscope, and three abnormal confocal endothelium images associated with diseases have been investigated in the proposed system. Promising results are presented and the performance of this system is compared with manual and two morphological based approaches. The average differences between the manual and the automatic cell densities calculated using S-PSO and two other morphological based approaches is 5%, 7% and 13% respectively. The developed system will be deployable as a clinical tool to underpin the expertise of ophthalmologists in analysing confocal corneal images.

Candida parapsilosis corneal graft infection from a single eye center: Histopathologic report of 2 cases

Fungal keratitis accounts for 6–53% of all cases of ulcerative keratitis in variable studies. The majority of cases are due to septate fungi. The abnormal cornea in cases of dry eye syndrome, chronic ulceration, erythema multiform and possibly HIV infection is infected more commonly with Candida, most commonly Candida albicans. Candida parapsilosis affects neonates and intensive care unit (ICU) patients and it has been recently found with increasing frequency. In a previous study on mycotic keratitis in our tertiary eye hospital, filamentous fungi were more commonly isolated than yeasts. We are presenting 2 successive cases of corneal graft infection by Candida parapsilosis referred to us from another eye center to attract the attention of ophthalmologists and health workers to such an infection.

Ophthalmic manifestations of systemic diseases--part 2: metabolic, infections, granulomatoses, demyelination, and skeletal dysplasias

The orbit and globe can be secondarily involved in various systemic diseases. These range from tumor and tumorlike conditions, metabolic, infective, inflammatory, granulomatous demyelinating diseases, and skeletal dysplasias. In this article, we discuss the imaging appearances of the remaining systemic pathologies affecting the orbit such as (1) endocrine or metabolic, (2) infectious, (3) inflammatory or granulomatous, (4) demyelinating diseases, and (5) skeletal dysplasias. As the imaging appearances of various systemic diseases tend to overlap, we also introduce a list of pattern-based systemic differential diagnoses for commonly encountered orbital imaging findings. Awareness of the imaging appearances of the various ophthalmic manifestations of systemic diseases can help a radiologist to suggest the most appropriate differential diagnosis to guide further workup and facilitate correct treatment.

[Ocular involvement with Candida albicans: report of 2 cases]

INTRODUCTION

Ocular involvement by Candida albicans is rare and may present as endogenous endophthalmitis or choroiditis. It occurs in the context of C. albicans septicemia, in the context of intensive care unit hospitalization or intravenous drug use. We report two cases referred to our department with different characteristics, background, diagnostic modalities and different courses.

OBSERVATIONS

A 37-year-old woman, with a history of intravenous drug use, presented with C. albicans endophthalmitis. Intravenous combination antifungal therapy was begun, but vitrectomy and intravitreal amphotericin B were performed due to worsening of the endophthalmitis. The second case was a 53-year-old man who was hospitalized in the intensive care unit for C. albicans septicemia with a left macular chorioretinitis. Intravenous antifungal therapy was initiated and allowed regression of the ocular lesion.

DISCUSSION

Our cases illustrate both types of ophthalmic involvement by candidiasis requiring different treatments with well-described recommendations: in the case of endophthalmitis, the use of vitrectomy and intravitreal amphotericin B injection in association with intravenous antifungal treatment, whereas parenteral antifungal treatment is often sufficient in the case of chorioretinitis.

CONCLUSION

Early detection, initiation of treatment and ophthalmologic monitoring are difficult but necessary in these populations non-compliant with follow-up or in intensive care units. The management of ocular candidiasis requires good collaboration between the ophthalmology, infectious diseases and intensive care unit departments.

Ocular fungal flora from healthy horses in Iran

OBJECTIVE

This study was carried out in order to isolate and identify the normal conjunctival fungal flora from Caspian miniature, Thoroughbred, Turkmen and Persian Arab breeds in Tehran, Iran.

MATERIALS AND METHODS

A total of seventy-two adult healthy horses were studied. Ocular samples were collected from right and left eyes by using sterile cotton swabs; samples were cultured on Sabouraud dextrose agar and incubated at 30°C for 7-10 days. Molds and yeasts were identified using macro and micro-morphological and physiological characteristics.

RESULTS AND CONCLUSION

Number of fungal colonies per eye varied between 0 and 123 colony forming units (CFUs). The most predominant fungal isolates were Aspergillus (19.9%), Rhizopus (15.9%) and Penicillium (15.1%). No significant differences were observed between types of eye fungal floras in different breeds. Caspian miniature horses had significantly the highest number of fungal isolates in compare with other breeds (P<0.001), however no significant difference was observed among other breeds under study. The fungal isolates were almost the same as with studies performed in other countries, although differences in species isolated could be related to geographic and climate difference.

Acanthamoeba, fungal, and bacterial keratitis: a comparison of risk factors and clinical features

PURPOSE

To determine risk factors and clinical signs that may differentiate between bacterial, fungal, and acanthamoeba keratitis among patients presenting with presumed infectious keratitis.

DESIGN

Hospital-based cross-sectional study.

METHODS

We examined the medical records of 115 patients with laboratory-proven bacterial keratitis, 115 patients with laboratory-proven fungal keratitis, and 115 patients with laboratory-proven acanthamoeba keratitis seen at Aravind Eye Hospital, Madurai, India, from 2006-2011. Risk factors and clinical features of the 3 organisms were compared using multinomial logistic regression.

RESULTS

Of 95 patients with bacterial keratitis, 103 patients with fungal keratitis, and 93 patients with acanthamoeba keratitis who had medical records available for review, 287 (99%) did not wear contact lenses. Differentiating features were more common for acanthamoeba keratitis than for bacterial or fungal keratitis. Compared to patients with bacterial or fungal keratitis, patients with acanthamoeba keratitis were more likely to be younger and to have a longer duration of symptoms, and to have a ring infiltrate or disease confined to the epithelium.

CONCLUSIONS

Risk factors and clinical examination findings can be useful for differentiating acanthamoeba keratitis from bacterial and fungal keratitis.

Outbreak of fungal endophthalmitis due to Fusarium oxysporum following cataract surgery

Outbreak of exogenous Fusarium endophthalmitis after cataract surgery was evaluated. Twenty patients developed postoperative endophthalmitis. In 19 eyes, pars plana vitrectomy (PPV) was performed, in 14 cases (74 %) with primary intraocular lens explantation. In one case, the PPV was not performed because of poor general condition of the patient. Symptoms of endophthalmitis (damaged vision, iritis, tyndallization in anterior chamber, hypopyon) occurred at intervals of 16-79 days (mean 31.3 days). Fungal etiology was documented in 12 eyes (60 %). Fusarium oxysporum was evidenced by culture and/or microscopy and confirmed by PCR and sequencing analysis. Eighteen (90 %) patients were treated with oral voriconazole (400 mg/day) for a period of 4-6 weeks. The final visual acuity was 6/15 in 1 case (5 %), 6/60 and worse in 17 eyes (85 %), and in 2 cases (10 %), enucleation had to be performed. Viscoelastic filling material was suggested the most likely source of infection. Endophthalmitis caused by Fusarium spp. are a potentially big threat for patients with serious impact on vision. Successful management of the infection is highly dependent on early diagnosis including species identification and antifungal susceptibility testing, and on aggressive and long-term treatment.

Ocular supersaturated self-nanoemulsifying drug delivery systems (S-SNEDDS) to enhance econazole nitrate bioavailability

Econazole nitrate (ECO) is a poorly water soluble antifungal drug. Having low aqueous solubility affects negatively its use for ocular treatment. This work aimed to prepare ocular supersaturated self-nanoemulsifying drug delivery systems (S-SNEDDS) of ECO employing hydroxypropyl methylcellulose as a precipitation inhibitor to improve the drug solubility by avoiding its precipitation after administration. Various oils, surfactants and co-surfactants were used to construct SNEDDS. The SNEDDS were evaluated for globule size, polydispersity index and their irritation potential using hen's egg test-chorioallantoic membrane (HET-CAM). The best SNEDDS was loaded with ECO and HPMC to prepare S-SNEDDS. In-vitro precipitation test of the S-SNEDDS was done to study the effect of the precipitation inhibitor. ECO permeation in rabbits' eyes from the selected S-SNEDDS (with and without HPMC) was evaluated. The results showed that SNEDDS-X consisting of 20% Capmul(®) MCM C10 as an oil, 60% Cremophor RH40(®) as a surfactant and 20% Transcutol(®) HP as co-surfactant possessed the lowest PDI value and a non-irritant effect on the CAM. The in-vitro precipitation test showed that the use of HPMC successfully sustained the supersaturated state by avoiding ECO precipitation. Higher Cmax, AUC0-8 and longer tmax confirm the development of a successful ECO-loaded S-SNEDDS.

Etiological agents of fungal endophthalmitis: diagnosis and management

Endophthalmitis caused by fungi is commonly diagnosed around the world in apparently healthy and immunocompromised individuals. An accurate clinical diagnosis for endophthalmitis confirmed by laboratory techniques is essential for early treatment with antifungal drugs, such as amphotericin B, imidazoles, and other antifungals. Here, we review endophthalmitis caused by fungi according to its classification into endogenous fungal endophthalmitis (EFE) and exogenous fungal endophthalmitis (EXFE). EFE is caused by endogenously acquired fungi, whereas the traumatic implantation of opportunistic fungal pathogens is the main feature of EXFE. We highlight the most important etiologies causing endophthalmitis and the steps required for a rapid diagnosis and management.

Type I interferon and lymphangiogenesis in the HSV-1 infected cornea - are they beneficial to the host?

Herpes simplex virus type 1 (HSV-1) is a highly successful pathogen that can result in significant human morbidity. Within the cornea, it was thought the initial recognition of the pathogen was through Toll-like receptors expressed on/in resident cells that then elicit pro-inflammatory cytokine production, activation of anti-viral pathways, and recruitment of leukocytes. However, our lab has uncovered a novel, TLR-independent innate sensor that supersedes TLR induction of anti-viral pathways following HSV-1 infection. In addition, we have also found HSV-1 induces the genesis of lymphatic vessels into the cornea proper by a mechanism independent of TLRs and unique in the field of neovascularization. This review will focus on these two innate immune events during acute HSV-1 infection of the cornea.

Fluorescent labeling of Acanthamoeba assessed in situ from corneal sectioned microscopy

Acanthamoeba keratitis is a serious pathogenic corneal disease, with challenging diagnosis. Standard diagnostic methods include corneal biopsy (involving cell culture) and in vivo reflection corneal microscopy (in which the visualization of the pathogen is challenged by the presence of multiple reflectance corneal structures). We present a new imaging method based on fluorescence sectioned microscopy for visualization of Acanthamoeba. A fluorescent marker (MT-11-BDP), composed by a fluorescent group (BODIPY) inserted in miltefosine (a therapeutic agent against Acanthamoeba), was developed. A custom-developed fluorescent structured illumination sectioned corneal microscope (excitation wavelength: 488 nm; axial/lateral resolution: 2.6 μm/0.4-0.6 μm) was used to image intact enucleated rabbit eyes, injected with a solution of stained Acanthamoeba in the stroma. Fluorescent sectioned microscopic images of intact enucleated rabbit eyes revealed stained Acanthamoeba trophozoites within the stroma, easily identified by the contrasted fluorescent emission, size and shape. Control experiments show that the fluorescent maker is not internalized by corneal cells, making the developed marker specific to the pathogen. Fluorescent sectioned microscopy shows potential for specific diagnosis of Acanthamoeba keratitis. Corneal confocal microscopy, provided with a fluorescent channel, could be largely improved in specificity and sensitivity in combination with specific fluorescent marking.

Detection of Candida and Aspergillus species DNA using broad-range real-time PCR for fungal endophthalmitis

BACKGROUND

The goal of this work is to establish a broad-range real-time polymerase chain reaction (PCR) diagnostic system for ocular fungal infection and to measure Candida and Aspergillus DNA in the ocular fluids obtained from unknown uveitis/endophthalmitis patients.

METHODS

After obtaining informed consent, intraocular fluids (aqueous humor and vitreous fluid samples) were collected from 54 patients with idiopathic uveitis or endophthalmitis. Samples were assayed for Candida or Aspergillus DNA using broad-range (18S rRNA sequences) quantitative real-time PCR.

RESULTS

Candida or Aspergillus DNA was detected in seven out of 54 patient ocular samples (13%). These PCR-positive samples showed significantly high copy numbers of Candida or Aspergillus DNA. On the other hand, fungal DNA was not detected in any of the other 46 samples collected from these idiopathic uveitis or endophthalmitis patients. In the one PCR-negative case, PCR did not detect any fungal genome in the sample, even though this patient was clinically suspected of having Candida endophthalmitis. Real-time PCR results were negative for fungal DNA in the bacterial endophthalmitis patients and in various uveitis patients. In addition, fungal DNA was also not detected in patients without ocular inflammation (controls).

CONCLUSIONS

Analysis of ocular samples by this broad-range real-time PCR method can be utilized for rapid diagnosis of patients suffering from unknown intraocular disorders such as idiopathic uveitis/endophthalmitis.

Endogenous filamentous fungal endophthalmitis--single-centre survey in patients with acute leukaemia or postallogeneic stem cell transplantation and review of the literature

Endogenous endophthalmitis caused by filamentous fungi has been infrequently described and its prognosis in immunocompromised patients is largely unknown. Patients were identified through a single-centre database containing patients with endophthalmitis. Cases published since 2002 were reviewed. Clinical and treatment features as well as outcomes were analysed. Six patients were identified from the database. Underlying conditions were haematological malignancies (HM) and/or allogeneic haematopoietic stem cell transplantation (HSCT). Three patients underwent vitrectomy. None of the patients survived and the median time from first evidence of endophthalmitis until death was 33 days. The median time from first evidence of an invasive fungal infection to endophthalmitis was only 5 days. Fifty-six patients were identified from the literature. The majority of these patients underwent vitrectomy (27) or enucleation (10) and received intraocular antifungal therapy (28). Only 13 (23%) of 56 patients experienced an improved vision. The survival rate was 52% in all 56 patients but was significantly less in patients with HM or post-HSCT when compared with all others (26% vs. 70%, respectively; P = 0.003). Endogenous endophthalmitis caused by filamentous fungi is frequently associated with a permanent decrease or loss of vision. This type of fungal infection carries a particular poor prognosis in patients with profound immunosuppression, requiring improved treatment strategies.

Microbial keratitis at a referral center in Brazil

To describe the epidemiological and laboratory characteristics of microbial keratitis at a referral center in Brazil. Charts of all patients referred to the Ocular Microbiology Laboratory at Federal University of São Paulo (UNIFESP) from July 1975 to September 2007 were retrospectively reviewed. The following data were recorded: age, gender, involved eye, use of ocular medication, previous trauma or surgery, contact lens wear and the results of laboratory cultures. The study included 6,804 corneal cultures. The mean age was 42.1 ± 21.4 years. The male-to-female ratio was 1.5:1. Positive cultures were obtained in 3,309 (48.6%) cases. Of these, bacteria were isolated in 2,699 (39.7%), fungi in 364 (5.3%) and Acanthamoeba in 246 (3.6%) samples. Positive bacterial cultures were 2.7-fold more frequent in patients with previous use of steroids (P < 0.01), and a 30% reduction in positive bacterial cultures was observed in patients with previous use of antibiotics (P < 0.01). A total of 1,524 patients (22.4%) had a past history of ocular surgery. Contact lens wearers showed a 1.7 times greater chance of having an Acanthamoeba-positive culture (P < 0.01). Previous ocular trauma was present in 1,118 (16.4%) cases and injury caused by plants showed a 3.8 times greater chance of a positive fungal culture (P < 0.01). Bacterial organisms were identified as the most frequent agent followed by fungi and Acanthamoeba. Prescription of steroids and antibiotics prior to corneal scrapings may modify the laboratory test results. Previous corneal surgery, contact lens wear and ocular trauma have been shown to be risk factors for bacterial, Acanthamoeba and fungal keratitis, respectively.

Ocular fungal infections

PURPOSE

Microbiology, clinical perspective of ocular fungal infections, and the experimental models were overviewed.

METHODS

Review of published studies were evaluated and personal experience was mentioned. In this review, clinical features of keratitis and endogenous and exogenous endophthalmitis are also mentioned, but this article mainly focused on laboratory diagnosis and the experimental models of ophthalmic mycoses.

RESULTS

Fungal infections were discussed according to the anatomical part of the eye involved in the disease. Trauma is the most important predisposing cause; the species of Fusarium, Aspergillus, and Candida are the most frequently isolated organisms. Laboratory methods, such as culture, remains the cornerstone of diagnosis; direct microscopic detection of fungal structures in ocular samples permits a rapid presumptive diagnosis. New approaches, such as serological and molecular methods, have been widely used in recent years. A variety of antifungals have been evaluated in the therapy of this condition. Experimental models would facilitate investigations exploring the pathophysiology, cell biology, genetics, immunology, and therapy of this disease.

CONCLUSIONS

Fungal infections of the eye continue to be an important cause of ocular morbidity, particularly in the developing world. Understanding ocular infections will improve the outcome of this condition.

Effect of formulation design and freeze-drying on properties of fluconazole multilamellar liposomes

Fluconazole-entrapped multilamellar liposomes were prepared using the thin-film hydration method. The effects of cholesterol molar ratio, charge-inducing agents, and α-tocopherol acetate on encapsulation efficiency values and in vitro drug release of multilamellar liposomes were studied. Freeze-dried liposomal products were prepared with or without cryoprotectants. Results showed that incorporation of stearylamine resulted in an increased entrapment of fluconazole, whereas incorporation of dicetyl phosphate decreased the drug entrapment efficiency. The incorporation of α-tocopherol acetate into fluconazole multilamellar liposomes resulted in the increase of entrapment efficiency of fluconazole liposomes. In vitro release studies revealed that incorporation of cholesterol into multilamellar liposomal formulations decreased drug permeability from formulations. Positively charged fluconazole multilamellar liposomes gave rise to a slow release rate compared to neutral liposomes whereas negatively charged fluconazole liposomes showed a rapid release rate. Physical stability studies showed that lyophilized cake of liposomes without cryoprotectants was compact and difficult to reconstitute compared to fluffy easily reconstituted cakes upon using cryoprotectants. Fluconazole retained in freeze-dried liposomes without cryoprotectants was 63.452% compared to 91.877% using three grams of trehalose as a cryoprotectant per gram lipid in positively charged multilamellar liposomes. Physical stability studies showed superior potentials of the lyophilized product after reconstitution in comparison with those of a solution product.

Invasive aspergillosis in developing countries

To review invasive aspergillosis (IA) in developing countries, we included those countries, which are mentioned in the document of the International Monetary Fund (IMF), called the Emerging and Developing Economies List, 2009. A PubMed/Medline literature search was performed for studies concerning IA reported during 1970 through March 2010 from these countries. IA is an important cause of morbidity and mortality of hospitalized patients of developing countries, though the exact frequency of the disease is not known due to inadequate reporting and facilities to diagnose. Only a handful of centers from India, China, Thailand, Pakistan, Bangladesh, Sri Lanka, Malaysia, Iran, Iraq, Saudi Arabia, Egypt, Sudan, South Africa, Turkey, Hungary, Brazil, Chile, Colombia, and Argentina had reported case series of IA. As sub-optimum hospital care practice, hospital renovation work in the vicinity of immunocompromised patients, overuse or misuse of steroids and broad-spectrum antibiotics, use of contaminated infusion sets/fluid, and increase in intravenous drug abusers have been reported from those countries, it is expected to find a high rate of IA among patients with high risk, though hard data is missing in most situations. Besides classical risk factors for IA, liver failure, chronic obstructive pulmonary disease, diabetes, and tuberculosis are the newly recognized underlying diseases associated with IA. In Asia, Africa and Middle East sino-orbital or cerebral aspergillosis, and Aspergillus endophthalmitis are emerging diseases and Aspergillus flavus is the predominant species isolated from these infections. The high frequency of A. flavus isolation from these patients may be due to higher prevalence of the fungus in the environment. Cerebral aspergillosis cases are largely due to an extension of the lesion from invasive Aspergillus sinusitis. The majority of the centers rely on conventional techniques including direct microscopy, histopathology, and culture to diagnose IA. Galactomannan, β-D glucan test, and DNA detection in IA are available only in a few centers. Mortality of the patients with IA is very high due to delays in diagnosis and therapy. Antifungal use is largely restricted to amphotericin B deoxycholate and itraconazole, though other anti-Aspergillus antifungal agents are available in those countries. Clinicians are aware of good outcome after use of voriconazole/liposomal amphotericin B/caspofungin, but they are forced to use amphotericin B deoxycholate or itraconazole in public-sector hospitals due to economic reasons.

Syndecan-1 regulates cell migration and fibronectin fibril assembly

Corneal scarring is a major cause of blindness worldwide and can result from the deposition of abnormal amounts of collagen fibers lacking the correct size and spacing required to produce a clear cornea. Collagen fiber formation requires a preformed fibronectin (FN) matrix. We demonstrate that the loss of syndecan1 (sdc1) in corneal stromal cells (CSC) impacts cell migration rates, the sizes and composition of focal and fibrillar adhesions, the activation of integrins, and the assembly of fibronectin into fibrils. Integrin and fibronectin expression are not altered on sdc1-null CSCs. Cell adhesion, spreading, and migration studies using low compared to high concentrations of FN and collagen I (CNI) or vitronectin (VN) with and without activation of integrins by manganese chloride show that the impact of sdc1 depletion on integrin activation varies depending on the integrin-mediated activity evaluated. Differences in FN fibrillogenesis and migration in sdc1-null CSCs are reversed by addition of manganese chloride but cell spreading differences remain. To determine if our findings on sdc1 were specific to the cornea, we compared the phenotypes of sdc1-null dermal fibroblasts with those of CSCs. We found that without sdc1, both cell types migrate faster; however, cell-type-specific differences in FN expression and its assembly into fibrils exist between these two cell types. Together, our data demonstrate that sdc1 functions to regulate integrin activity in multiple cell types. Loss of sdc1-mediated integrin function results in cell-type specific differences in matrix assembly. A better understanding of how different cell types regulate FN fibril formation via syndecans and integrins will lead to better treatments for scarring and fibrosis.