Microbial keratitis in patients infected with the human immunodeficiency virus

Itraconazole loaded nano-structured lipid carrier for topical ocular delivery: Optimization and evaluation

BACKGROUND & OBJECTIVES

Low penetration efficiency and retention time are the main therapeutic concerns that make it difficult for most of the drugs to be delivered to the intraocular tissues. These challenging issues are often related to those drugs, which have low or poor solubility and low permeability. The goal of this study was designed to develop nanostructured lipid carriers (NLCs) loaded with itraconazole (ITZ) with the objective of enhancing topical ocular permeation and thereby improving clinical efficacy.

MATERIALS AND METHODS

ITZ-loaded NLCs were fabricated by a high-speed homogenization technique using surfactant (Poloxamer 407), and lipids (stearic acid and oleic acid). Optimization of formulations was performed by 3 level factorial design and the selected formulation (F6) was evaluated by differential scanning calorimetry and transmission electron microscopy. Antifungal activity was assessed by measuring the zone of inhibition and irritation potential using the HET-CAM test.

RESULTS

The independent variables (lipid ratio-X1 and percentage of emulsifier-X2) have a positive impact on percentage entrapment efficiency (Y2) and percentage release (Y3) but have a negative impact on particle size (Y1). Based on the better entrapment efficiency (94.65%), optimum particle size (150.67 nm), and percentage cumulative drug release (68.67%), batch F6 was selected for further evaluation. Electron microscopic images revealed that the prepared particles are spherical and have nano size. Antifungal studies demonstrated enhancement in the zone of inhibition by formulation F6 as compared to a commercial eye drop. The non-irritancy of optimized formulation (F6) was confirmed with a zero score.

INTERPRETATION & CONCLUSION

In summary, the optimized NLCs seem to be a potent carrier for the effective delivery of itraconazole in ocular therapy.

Intracorneal Amphotericin B Injection in a Case of Indolent Candidal Keratitis

Ocular candidiasis is one of the opportunistic infection occurring in human body. Pathogenesis wise, Candida is very virulent and slow growing organism. We report a case of 76-year-old female with left eye candidal stromal abscess, not responding to topical and oral antifungal drugs. Patient was administered intrastromal amphotericin B injection in the affected eye. Four midstromal injections were given in the areas surrounding the corneal abscess. A total of approximately 0.05 mL of amphotericin B, 5 μg per 0.1 mL, was administered. Within next four weeks, the eye became completely quiet with healed epithelial defect and corneal scarring. Intracorneal injection of amphotericin B is a safe and effective treatment option for recurrent and recalcitrant fungal infections.

Candida albicans scleral abscess in a HIV-positive patient and its successful resolution with antifungal therapy-a first case report

Background

Fungal infection of the sclera is very rare. No case of fungal scleral abscess in a HIV-positive patient has been reported. We report a case of scleral abscess caused by Candida albicans and its successful resolution following antifungal therapy in a HIV-positive patient.

Findings

A 57-year-old diabetic Asian (Indian) who was on highly active antiretroviral therapy for the last 10 years presented with 2 weeks’ history of redness in his right eye. Examination revealed localised scleral inflammation with central ulceration in the inferior quadrant of the right eye. Initially, the ulcer scrapings revealed no microbial organism. Progression of ulcer although on empirical antibiotic therapy required repeat scrapings which showed Candida albicans species in culture sensitive to amphotericin and natamycin. Aggressive topical and systemic antifungals resulted in dramatic and complete healing of the ulcer in 3 weeks. Vision was well maintained at 20/30 throughout the treatment course, and the fundus remained normal.

Conclusions

This is the first ever case of fungal scleral abscess in a HIV patient to be reported emphasizing there is a need for high vigilance to suspect an infective aetiology of scleritis in patients with immunocompromised status. Prompt microbial assessment and appropriate antifungals can decrease morbidity in these unusual but serious cases as illustrated in this case.

Candida albicans scleral abscess in a HIV-positive patient and its successful resolution with antifungal therapy-a first case report

Background

Fungal infection of the sclera is very rare. No case of fungal scleral abscess in a HIV-positive patient has been reported. We report a case of scleral abscess caused by Candida albicans and its successful resolution following antifungal therapy in a HIV-positive patient.

Findings

A 57-year-old diabetic Asian (Indian) who was on HAART for the last 10 years presented with 2 weeks history of redness in his right eye. Examination revealed localised scleral inflammation with central ulceration in the inferior quadrant of the right eye. Initially, the ulcer scrapings revealed no microbial organism. Progression of ulcer although on empirical antibiotic therapy required repeat scrapings which showed C. albicans species in culture sensitive to amphotericin and natamycin. Aggressive topical and systemic antifungals resulted in dramatic and complete healing of the ulcer in 3 weeks. Vision was well maintained at 20/30 throughout the treatment course and the fundus remained normal.

Conclusions

This is the first ever case of fungal scleral abscess in an HIV patient to be reported emphasising there is a need for high vigilance to suspect an infective aetiology of scleritis in patients with immunocompromised status. Prompt microbial assessment and appropriate antifungals can decrease morbidity in these unusual but serious cases as illustrated in this case.

[Purulent corneal ulcers: etiology, pathogenesis, classification]

Advanced purulent corneal ulcer, as well as abscess, is a serious vision-threatening condition notable for its fulminant course and possible loss of the eye due to endophthalmitis. Its leading causes, pathogenesis, and classifications are described and analyzed in this paper.

Multicentric T-cell lymphoma presenting as inferior palpebral swelling in a Standardbred mare

A 6-year-old Standardbred mare that presented with bilateral palpebral swelling and a left corneal ulcer was diagnosed with a multicentric T-cell lymphoma. Other clinical findings included submandibular lymphadenopathy and oedema, pharyngeal oedema and rhinitis. Prior to euthanasia the horse developed keratomalacia, the onset of which was coincidental with the use of high doses of topical and systemic corticosteroids. Although an unusual presentation, palpebral swelling should be considered as a clinical sign of lymphoma.

Calcineurin controls drug tolerance, hyphal growth, and virulence in Candida dubliniensis

Candida dubliniensis is an emerging pathogenic yeast species closely related to Candida albicans and frequently found colonizing or infecting the oral cavities of HIV/AIDS patients. Drug resistance during C. dubliniensis infection is common and constitutes a significant therapeutic challenge. The calcineurin inhibitor FK506 exhibits synergistic fungicidal activity with azoles or echinocandins in the fungal pathogens C. albicans, Cryptococcus neoformans, and Aspergillus fumigatus. In this study, we show that calcineurin is required for cell wall integrity and wild-type tolerance of C. dubliniensis to azoles and echinocandins; hence, these drugs are candidates for combination therapy with calcineurin inhibitors. In contrast to C. albicans, in which the roles of calcineurin and Crz1 in hyphal growth are unclear, here we show that calcineurin and Crz1 play a clearly demonstrable role in hyphal growth in response to nutrient limitation in C. dubliniensis. We further demonstrate that thigmotropism is controlled by Crz1, but not calcineurin, in C. dubliniensis. Similar to C. albicans, C. dubliniensis calcineurin enhances survival in serum. C. dubliniensis calcineurin and crz1/crz1 mutants exhibit attenuated virulence in a murine systemic infection model, likely attributable to defects in cell wall integrity, hyphal growth, and serum survival. Furthermore, we show that C. dubliniensis calcineurin mutants are unable to establish murine ocular infection or form biofilms in a rat denture model. That calcineurin is required for drug tolerance and virulence makes fungus-specific calcineurin inhibitors attractive candidates for combination therapy with azoles or echinocandins against emerging C. dubliniensis infections.

[Severe infectious keratitis in renal transplant patient: a case report]

Keratitis occurring in renal transplant patients are often severe, with difficult management. We describe the case of a renal transplant patient, 44 year-old man, with history of recurrent herpetic keratitis, which developed an impending corneal perforation. Conjunctival smear showed the presence of amoebic cysts. Anti-amoebic treatment was undertaken in addition with oral aciclovir, and a therapeutic penetrating keratoplasty was performed. An ulceration of the graft occurred within five months. Ocular samples showed the presence of Candida albicans. Despite aggressive antifungal therapy, he required a second therapeutic penetrating keratoplasty for graft perforation. One month later, we noted a recurrence of the ulcer with corneal thinning which evolved to perforation.

Anterior Segment and External Ocular Disorders Associated with Human Immunodeficiency Virus Disease

The eye is a common site for complications of human immunodeficiency virus (HIV) infection. Although cytomegalovirus retinitis remains the most prevalent of the blinding ocular disorders that can occur in individuals with the acquired immunodeficiency syndrome (AIDS), several important HIV-associated disorders may involve the anterior segment, ocular surface, and adnexae. Some of these entities, such as Kaposi sarcoma, were well described, but uncommon, before the HIV epidemic. Others, like microsporidial keratoconjunctivitis, have presentations that differ between affected individuals with HIV disease and those from the general population who are immunocompetent. The treatment of many of these diseases is challenging because of host immunodeficiency. Survival after the diagnosis of AIDS has increased among individuals with HIV disease because of more effective antiretroviral therapies and improved prophylaxis against, and treatment of, opportunistic infections. This longer survival may lead to an increased prevalence of anterior segment and external ocular disorders. In addition, the evaluation and management of disorders such as blepharitis and dry eye, which were previously overshadowed by more severe, blinding disorders, may demand increased attention, as the general health of this population improves. Not all individuals infected with HIV receive potent antiretroviral therapy, however, because of socioeconomic or other factors, and others will be intolerant of these drugs or experience drug failure. Ophthalmologists must, therefore, still be aware of the ocular findings that develop in the setting of severe immunosuppression. This article reviews the spectrum of HIV-associated anterior segment and external ocular disorders, with recommendations for their evaluation and management.

Clinical characteristics and outcome of Candida keratitis

PURPOSE

To characterize the clinical features and therapeutic outcome of Candida keratitis.

DESIGN

Retrospective, observational case series.

METHODS

We reviewed 26 patients treated for Candida keratitis, including two with recurrent keratitis and one with bilateral infection.

RESULTS

Of 29 keratitis episodes resulting from Candida albicans (n = 20) or Candida parapsilosis (n = 9), 16 (55%) complicated chronic ocular surface disease, and nine (31%) followed previous keratoplasty. Only two were clinically suspected to have keratomycosis at initial presentation, and 21 (72%) used antibacterial therapy before corneal scrapings. Reconstructive keratoplasty occurred more often in previously grafted eyes (P = .03). Visual outcome was 20/60 or better in six (100%) medically treated eyes with good presenting visual acuity but in only five eyes (24%) with worse initial vision (P = .002).

CONCLUSIONS

Candida keratitis is an opportunistic infection of a compromised cornea that often is misdiagnosed initially and, despite antifungal therapy, occasionally requires corneal grafting.

Polymicrobial keratomycosis in a three-year-old child

PURPOSE

To describe a previously unreported case of polymicrobial mycotic keratitis caused by an association between Candida lusitaniae, C. parapsilosis, and Geotrichum candidum.

METHODS

A three-year-old child with an antecedent trauma with vegetable matter and a prolonged use of corticosteroid eyedrops developed fungal keratitis.

RESULTS

The isolates of the corneal scraping using Sabaraud dextrose agar grew C. lusitaniae, C. parapsilosis, and G. candidum. After topical 0.2% and systemic fluconazole treatment, the corneal lesion resolved with no recurrence.

CONCLUSIONS

Corneal trauma with vegetables and the indiscriminate use of corticosteroids are important risk factors for mycotic keratitis. A combination of topical 0.2% and systemic fluconazole therapy was effective in the treatment of this mycotic association. This is the first report of fungal keratitis caused by C. lusitaniae and G. candidum.

Fungal keratitis at the new york eye and ear infirmary

INTRODUCTION

This study was designed to review the clinical experience at our institution with fungal keratitis during a 16-year period.

MATERIALS AND METHODS

A review of the clinical and microbiology records of the New York Eye and Infirmary identified 61cases of fungal keratitis in 57 patients between January 1, 1987 and June 1, 2003. The medical records of all patients were retrospectively reviewed to better delineate patient demographics, risk factors, etiologic organisms, treatment, and outcomes.

RESULTS

A total of 5083 positive corneal cultures were recorded'from January 1, 1987 to June 1, 2003. Sixty-one eyes in 57 patients (37 women) were positive for fungus (1.2%). Three'patients had bilateral simultaneous infections. Candida albicans accounted for 29 of 61 cases (48%). Human immunodeficiency virus (HIV) seropositivity (15 eyes), chronic ocular surface disease (14 eyes), and trauma (7 eyes) were the most commonly associated risk factors.

CONCLUSIONS

Our experience with fungal keratitis in the northeastern United States appears to be different than those reported from other areas of the United States. Serologic positivity for HIV and chronic ocular surface disease were the most common associated risk factors followed by trauma, herpes simplex keratitis, and contact lens use. Candida species predominated, whereas filamentous fungi were uncommon.

Bacillus megaterium Delayed Onset Lamellar Keratitis After LASIK

PURPOSE

To report the history and clinical presentation of a 23-year-old man who developed delayed onset lamellar keratitis in his right eye 2 weeks after uneventful LASIK for correction of myopia.

METHODS

Initial clinical presentation suggested an infectious etiology, which led to therapeutic elevation of the LASIK flap and further microbiologic investigation with bacterial cultures.

RESULTS

Bacterial cultures revealed Bacillus megaterium, which was sensitive to all antibiotics against which it was tested. Twenty-four hours after initiating aggressive topical and oral antibiotic therapy, symptomatic relief occurred in the affected eye. The patient's uncorrected final visual acuity at 1-year follow-up was 20/15 in the right eye, and the stromal bed developed a faint peripheral non-visually significant scar.

CONCLUSIONS

This case is an unusual presentation and course for microbial keratitis following LASIK, which occurred despite aseptic technique and fluoroquinolone antibiotic prophylaxis. Following refractive surgery one should be prepared to culture the lamellar interface in cases of suspected microbial keratitis and begin aggressive antibiotic therapy.

Recurrent corneal erosion (RCE) secondary to lattice dystrophy in a patient with acquired immune deficiency syndrome (AIDS)

BACKGROUND

We present a case of an Acquired Immune Deficiency Syndrome (AIDS) patient with recurrent erosion (RCE) secondary to lattice corneal dystrophy. As a human immunodeficiency virus (HIV)-infected patient becomes more immunocompromised, the ocular surface defense mechanisms may be compromised. Lattice dystrophy, RCE, and modifying approaches to the management of RCE in an HIV-positive or AIDS patient are reviewed.

CASE REPORT

A 49-year-old man presented with RCE. His ocular history included lattice corneal dystrophy OU, recurrent corneal erosion O.S., and herpes simplex virus keratitis O.S. Systemic history included hepatitis C and HIV infection with a diagnosis of AIDS with secondary Pneumocystis carinii pneumonia. Viral load was 35533 HIV-RNA (ribonucleic acid) molecules/ml of plasma and CD4 lymphocyte count 99 cells/mm3. Acuities were O.D. 20/80 and O.S. 20/50. The abrasion was treated with cycloplegia and bacitracin/polymyxin B ointment q.i.d. O.S. and it resolved in 3 days.

CONCLUSION

Management of lattice dystrophy with secondary RCE in an AIDS patient requires that the clinician be familiar with the patient's immune status. As the CD4 count declines and the viral load increases, the patient is at higher risk for opportunistic anterior segment infections. Clinicians need to monitor these patients closely for potential complicating ocular sequelae of AIDS such as herpes zoster ophthalmicus, herpes simplex keratitis, fungal/bacterial keratitis, and keratoconjunctivitis sicca. Our patient responded well to antibiotic therapy and cycloplegia. The importance of daily monitoring of immunocompromised patients is emphasized.

Conjunctival flora in patients with human immunodeficiency virus infection

PURPOSE

To compare the conjunctival flora of human immunodeficiency virus (HIV)-positive and HIV-negative patients. Also, to assess the prophylactic effect of oral clarithromycin against Mycobacterium avium complex on the conjunctival flora of HIV-positive patients.

METHODS

Ninety-four eyes of 47 HIV-positive patients and 122 eyes of 61 control patients were examined. All participants had a detailed anterior segment examination, including conjunctival cultures and laboratory blood tests. Culture results for different organisms were evaluated by chi-square analysis between the groups. The effect of systemic antibiotic treatment on the conjunctival flora of patients with HIV infection was evaluated by chi-square analysis.

RESULTS

Bacterial organisms in the conjunctival sac were detected in four out of 28 (14.3%) eyes of HIV-positive patients treated with systemic clarithromycin and in 32 out of 66 (48.5%) eyes of HIV-positive patients without systemic clarithromycin treatment (p < 0.01). The CD4-positive T-cell counts in these groups were 158/microl and 416/microl, respectively (p < 0.01). Bacterial organisms were also detected in 46 of 122 (37.7%) control eyes. No difference was observed in the types and proportions of organisms isolated from the conjunctiva between HIV-positive patients without systemic clarithromycin treatment and controls.

CONCLUSION

There was no difference between the conjunctival flora of HIV-negative and HIV-positive patients. Systemic clarithromycin treatment decreased the conjunctival flora of HIV patients, including those who had a CD4 count that was less than 50/microl.

Current perspectives on ophthalmic mycoses

Fungi may infect the cornea, orbit and other ocular structures. Species of Fusarium, Aspergillus, Candida, dematiaceous fungi, and Scedosporium predominate. Diagnosis is aided by recognition of typical clinical features and by direct microscopic detection of fungi in scrapes, biopsy specimens, and other samples. Culture confirms the diagnosis. Histopathological, immunohistochemical, or DNA-based tests may also be needed. Pathogenesis involves agent (invasiveness, toxigenicity) and host factors. Specific antifungal therapy is instituted as soon as the diagnosis is made. Amphotericin B by various routes is the mainstay of treatment for life-threatening and severe ophthalmic mycoses. Topical natamycin is usually the first choice for filamentous fungal keratitis, and topical amphotericin B is the first choice for yeast keratitis. Increasingly, the triazoles itraconazole and fluconazole are being evaluated as therapeutic options in ophthalmic mycoses. Medical therapy alone does not usually suffice for invasive fungal orbital infections, scleritis, and keratitis due to Fusarium spp., Lasiodiplodia theobromae, and Pythium insidiosum. Surgical debridement is essential in orbital infections, while various surgical procedures may be required for other infections not responding to medical therapy. Corticosteroids are contraindicated in most ophthalmic mycoses; therefore, other methods are being sought to control inflammatory tissue damage. Fungal infections following ophthalmic surgical procedures, in patients with AIDS, and due to use of various ocular biomaterials are unique subsets of ophthalmic mycoses. Future research needs to focus on the development of rapid, species-specific diagnostic aids, broad-spectrum fungicidal compounds that are active by various routes, and therapeutic modalities which curtail the harmful effects of fungus- and host tissue-derived factors.

Pseudomonas-Candida interactions: an ecological role for virulence factors

Bacterial-fungal interactions have great environmental, medical, and economic importance, yet few have been well characterized at the molecular level. Here, we describe a pathogenic interaction between Pseudomonas aeruginosa and Candida albicans, two opportunistic pathogens. P. aeruginosa forms a dense biofilm on C. albicans filaments and kills the fungus. In contrast, P. aeruginosa neither binds to nor kills yeast-form C. albicans. Several P. aeruginosa virulence factors that are important in disease are involved in the killing of C. albicans filaments. We propose that many virulence factors studied in the context of human infection may also have a role in bacterial-fungal interactions.

Fungal and parasitic infections of the eye

The unique structure of the human eye as well as exposure of the eye directly to the environment renders it vulnerable to a number of uncommon infectious diseases caused by fungi and parasites. Host defenses directed against these microorganisms, once anatomical barriers are breached, are often insufficient to prevent loss of vision. Therefore, the timely identification and treatment of the involved microorganisms are paramount. The anatomy of the eye and its surrounding structures is presented with an emphasis upon the association of the anatomy with specific infection of fungi and parasites. For example, filamentous fungal infections of the eye are usually due to penetrating trauma by objects contaminated by vegetable matter of the cornea or globe or, by extension, of infection from adjacent paranasal sinuses. Fungal endophthalmitis and chorioretinitis, on the other hand, are usually the result of antecedent fungemia seeding the ocular tissue. Candida spp. are the most common cause of endogenous endophthalmitis, although initial infection with the dimorphic fungi may lead to infection and scarring of the chorioretina. Contact lens wear is associated with keratitis caused by yeasts, filamentous fungi, and Acanthamoebae spp. Most parasitic infections of the eye, however, arise following bloodborne carriage of the microorganism to the eye or adjacent structures.

Fungal and parasitic infections of the eye

The unique structure of the human eye as well as exposure of the eye directly to the environment renders it vulnerable to a number of uncommon infectious diseases caused by fungi and parasites. Host defenses directed against these microorganisms, once anatomical barriers are breached, are often insufficient to prevent loss of vision. Therefore, the timely identification and treatment of the involved microorganisms are paramount. The anatomy of the eye and its surrounding structures is presented with an emphasis upon the association of the anatomy with specific infection of fungi and parasites. For example, filamentous fungal infections of the eye are usually due to penetrating trauma by objects contaminated by vegetable matter of the cornea or globe or, by extension, of infection from adjacent paranasal sinuses. Fungal endophthalmitis and chorioretinitis, on the other hand, are usually the result of antecedent fungemia seeding the ocular tissue. Candida spp. are the most common cause of endogenous endophthalmitis, although initial infection with the dimorphic fungi may lead to infection and scarring of the chorioretina. Contact lens wear is associated with keratitis caused by yeasts, filamentous fungi, and Acanthamoebae spp. Most parasitic infections of the eye, however, arise following bloodborne carriage of the microorganism to the eye or adjacent structures.

Epibulbar allergic granulomatous nodules in a human immunodeficiency virus-positive patient

PURPOSE

To report an unusual epibulbar inflammatory process in a patient with human immunodeficiency virus (HIV).

METHODS

Case report. A 32-year-old man developed fleshy epibulbar nodules on his right conjunctiva and cornea after being treated for conjunctivitis. A biopsy of the lesions was done, and the specimen was processed for histopathologic examination.

RESULTS

The biopsy specimen contained inflammatory cells, including an eosinophilic abscess. The diagnosis was allergic granulomatous nodules.

CONCLUSION

This case illustrates the occurrence of epibulbar allergic granulomatous nodules in an HIV-positive patient.

Antimicrobial management of presumed microbial keratitis: guidelines for treatment of central and peripheral ulcers

AIMS

To determine the quantitative relation between the major risk factors for microbial keratitis of previous ocular surface disease and contact lens wear and central and peripheral infiltration, often associated with ulceration, in order to establish a rational chemotherapeutic management algorithm.

METHODS

Data from 55 patients were collected over a 10 month period. All cases of presumed microbial keratitis where corneal scrapes had been subjected to microbiological examination were included. Risk factor data and laboratory outcome were recorded. Antimicrobial regimens used to treat each patient were documented.

RESULTS

57 episodes of presumed microbial keratitis were identified from 55 patients, 24 male and 31 female. There were 30 central infiltrates and 27 peripheral infiltrates of which 28 were culture positive (73% of central infiltrates, 22% of peripheral infiltrates). 26 patients had worn contact lenses of whom 12 had culture positive scrapes (9/14 for central infiltrates, 3/12 for peripheral infiltrates). 31 patients had an ocular surface disease of whom five previous herpes simplex virus keratitis patients developed secondary bacterial infection. Anterior chamber activity and an infiltrate size > or = 4 mm2 were more common with culture positive central infiltrates than peripheral infiltrates (chi 2 test = 11.98, p < 0.001).

CONCLUSIONS

Predisposing factors for "presumed" microbial keratitis, either central or peripheral, were: ocular surface disease (26/57 = 45.6%), contact lens wear (26/57 = 45.6%), and previous trauma (5/57 = 8.8%). Larger ulceration (> or = 4 mm2) with inflammation was more often associated with positive culture results for central infiltration. None of these four variables (contact lens wear, ocular surface disease, ulcer size, anterior chamber activity) were of intrinsic value in predicting if a peripheral infiltrate would yield identifiable micro-organisms. Successful management of presumed microbial keratitis is aided by a logical approach to therapy, with the use of a defined algorithm of first and second line broad spectrum antimicrobials, for application at each stage of the investigative and treatment process considering central and peripheral infiltration separately.