Fusarium keratitis and endophthalmitis associated with lens contact wear

The Role of Biofilms in Contact Lens Associated Fungal Keratitis

Biofilm formation is an important microbial strategy for fungal pathogens, such as Fusarium, Aspergillus, and Candida, to establish keratitis in patients wearing soft contact lenses. Despite the well-documented 2006 outbreak of Fusarium keratitis that eventually led to the withdrawal of the Bausch & Lomb multipurpose lens care solution ReNu with MoistureLoc ("MoistureLoc") from the global market, contact lens care systems and solutions currently available on the market do not specifically target fungal biofilms. This is partially due to the lack of recognition and understanding of important roles that fungal biofilms play in contact lens associated fungal keratitis (CLAFK). This review aims to reemphasize the link between fungal biofilms and CLAFK, and deepen our comprehension of its importance in pathogenesis and persistence of this medical device-related infection.

Fusarium spp. in Human Disease: Exploring the Boundaries between Commensalism and Pathogenesis

Fusarium is a large fungal genus that is widely distributed in the environment, mostly known for its plant pathogenicity. Rarely, it is involved in human pathology, where the type of infection caused is highly dependent upon the portal of entry and the immune status of the host. The study at hand aims to summarize routine methods used in diagnosing such infections as well as more advanced molecular diagnostic methods, techniques that can play a huge role in differentiating between colonization and infection when trying to decide the therapeutic outcome. Consequently, to further support our findings, two different strains (one isolated from corneal scrapings and one isolated from purulent discharge) were analyzed in a clinical context and thoroughly tested using classical and modern diagnostic methods: identification by macroscopical and microscopical examinations of the culture and mass spectrometry, completed by molecular methods such as PCR for trichothecene and ERIC-PCR for genetic fingerprinting. Isolation of a clinically relevant Fusarium spp. from a sample still remains a diagnostic challenge for both the clinician and the microbiologist, because differentiating between colonization and infection is very strenuous, but can make a difference in the treatment that is administered to the patient.

Risk factors and microbiological characteristics: from bacterial keratitis with hypopyon to keratitis-related endophthalmitis

PURPOSE

To compare the clinical and microbiological characteristics in patients with bacterial keratitis with hypopyon (BKH), bacterial keratitis-related endophthalmitis (BKE), and bacterial endophthalmitis without keratitis (BE).

METHODS

Data from all inpatients who were clinically diagnosed with BKH, BKE, and BE from 2018 to 2020 were collected retrospectively. The demographics, predisposing risk factors, clinical characteristics, microbiological profiles, and antibiotic susceptibility of the patients were evaluated.

RESULTS

Approximately 9.46% (28/296) of eyes with BKH progressed to endophthalmitis. The hypopyon (OR = 5.35, 95% CI: 2.17-7.08) and corneal perforation (OR = 2.47, 95% CI: 1.04-4.86) were significantly related to the development of BKE. The odds ratios for hypopyon of less than 1 mm, 1-3 mm, and greater than 3 mm were 1, 2.09 (95% CI: 1.17-3.15), and 4.12 (95% CI:2.59-5.68), respectively. The predominant causative pathogen was Staphylococcus epidermidis (36.43%, 38.89%), followed by Streptococci (14.73%, 16.67%), Staphylococcus aureus (8.53%, 7.79%), and Pseudomonas aeruginosa (9.30%, 7.14%) in eyes with BKH and BE. However, the main pathogens were Pseudomonas aeruginosa (37.50%) and Staphylococcus aureus (31.25%) in eyes with BKE. In the BKH, BKE, and BE groups, almost 100% of Staphylococcus aureus isolates were sensitive to vancomycin (97.70%, 100%, 95.56%), about a half were sensitive to fluoroquinolones (51.85%, 39.90%, 62.34%), and approximately 30% were sensitive to trimethoprim/sulfa (27.77%, 21.56%, 33.56%) and cefazolin (41.47%, 20.31%, 38.81%). The susceptibility of Pseudomonas aeruginosa to fluoroquinolones antibiotics was 55.75%, 66.67%, and 62.58%, respectively, in the three groups.

CONCLUSIONS

The height of hypopyon and corneal perforation are risk factors for progression to endophthalmitis in eyes with bacterial keratitis. When Staphylococcus aureus and Pseudomonas aeruginosa are identified, vigilance is required for advanced endophthalmitis.

Recent Advances in Photodynamic Therapy against Fungal Keratitis

Fungal keratitis is a serious clinical infection on the cornea caused by fungi and is one of the leading causes of blindness in Asian countries. The treatment options are currently limited to a few antifungal agents. With the increasing incidence of drug-resistant infections, many patients fail to respond to antibiotics. Riboflavin-mediated corneal crosslinking (similar to photodynamic therapy (PDT)) for corneal ectasia was approved in the US in the early 2000s. Current evidence suggests that PDT could have the potential to inhibit fungal biofilm formation and overcome drug resistance by using riboflavin and rose bengal as photosensitizers. However, only a few clinical trials have been initiated in anti-fungal keratitis PDT treatment. Moreover, the removal of the corneal epithelium and repeated application of riboflavin and rose bengal are required to improve drug penetration before and during PDT. Thus, an improvement in trans-corneal drug delivery is mandatory for a successful and efficient treatment. In this article, we review the studies published to date using PDT against fungal keratitis and aim to enhance the understanding and awareness of this research area. The potential of modifying photosensitizers using nanotechnology to improve the efficacy of PDT on fungal keratitis is also briefly reviewed.

An Overview of the Management of the Most Important Invasive Fungal Infections in Patients with Blood Malignancies

In patients with hematologic malignancies due to immune system disorders, especially persistent febrile neutropenia, invasive fungal infections (IFI) occur with high mortality. Aspergillosis, candidiasis, fusariosis, mucormycosis, cryptococcosis and trichosporonosis are the most important infections reported in patients with hematologic malignancies that undergo hematopoietic stem cell transplantation. These infections are caused by opportunistic fungal pathogens that do not cause severe issues in healthy individuals, but in patients with hematologic malignancies lead to disseminated infection with different clinical manifestations. Prophylaxis and creating a safe environment with proper filters and air pressure for patients to avoid contact with the pathogens in the surrounding environment can prevent IFI. Furthermore, due to the absence of specific symptoms in IFI, rapid and accurate diagnosis reduces the mortality rate of these infections and using molecular techniques along with standard mycological methods will improve the diagnosis of disseminated fungal infection in patients with hematologic disorders. Amphotericin B products, extended-spectrum azoles, and echinocandins are the essential drugs to control invasive fungal infections in patients with hematologic malignancies, and according to various conditions of patients, different results of treatment with these drugs have been reported in different studies. On the other hand, drug resistance in recent years has led to therapeutic failures and deaths in patients with blood malignancies, which indicates the need for antifungal susceptibility tests to use appropriate therapies. Life-threatening fungal infections have become more prevalent in patients with hematologic malignancies in recent years due to the emergence of new risk factors, new species, and increased drug resistance. Therefore, in this review, we discuss the different dimensions of the most critical invasive fungal infections in patients with hematologic malignancies and present a list of these infections with different clinical manifestations, treatment, and outcomes.

Multidrug-resistant Fusarium keratitis: diagnosis and treatment considerations

Mycotic keratitis is an ocular infective process derived from any fungal species capable of corneal invasion. Despite its rarity in developed countries, its challenging and elusive diagnosis may result in keratoplasty or enucleation following failed medical management. Filamentous fungi such as Fusarium are often implicated in mycotic keratitis. Bearing greater morbidity than its bacterial counterpart, mycotic keratitis requires early clinical suspicion and initiation of antifungal therapy to prevent devastating consequences. We describe a case of multidrug-resistant mycotic keratitis in a 46-year-old man who continued to decline despite maximal therapy and therapeutic keratoplasty. Finally, enucleation was performed as a means of source control preventing dissemination of a likely untreatable fungal infection into the orbit. Multidrug-resistant Fusarium is rare, and may progress to endophthalmitis. We discuss potential management options which may enhance diagnosis and outcome in this condition.

Risk factors for endophthalmitis requiring evisceration or enucleation

Endophthalmitis has devastating sequelae resulting in blindness and even loss of eyeball. Although the prognosis of endophthalmitis has much improved with the advances of antibiotics and vitreoretinal surgery, of the number of patients that required evisceration or enucleation is still significant. We retrospectively reviewed the charts of 210 eyes of 210 patients with endophthalmitis andcompared the group that required evisceration or enucleation with those that received salvaging therapies. Regression analysis was used to identify the risk factors for evisceration or enucleation. Thirty eyes (14.3%) underwent enucleation or evisceration. The group of eviscerated or enucleated eyes were older (58.7 vs. 42.2 years, p < 0.001), had more women (56.7% vs. 22.2%, p = 0.003), had poorer initial visual acuity (2.79 vs. 2.10 LogMAR, p < 0.001), and had longer duration before intervention (18.03 vs. 5.74 days, p = 0.031). The most common primary indications for endophthalmitis were infections from corneal ulcer (50.0% vs. 4.4%, p < 0.001) andfrom endogenous source (23.3% vs. 5.6%, p < 0.001). Less common indications were trauma (26.7% vs. 67.8%, p < 0.001) and postoperative (6.7% vs. 22.2%, p = 0.049) endophthalmitis. After adjusting for confounding factors, corneal ulcer-related endophthalmitis, endogenous endophthalmitis and initial visual acuity were the independent risk factors for evisceration or enucleation.

[Keratomycosis due to Fusarium oxysporum treated with the combination povidone iodine eye drops and oral fluconazole]

In developing countries where systemic antifungal are often unavailable, treatment of filamentous fungi infection as Fusarium is sometimes very difficult to treat. We report the case of a keratomycosis due to Fusarium oxysporum treated by povidone iodine eye drops and oral fluconazole. The diagnosis of abscess in the cornea was retained after ophthalmological examination for a 28-year-old man with no previous ophthalmological disease, addressed to the Ophthalmological clinic at the University Hospital Le Dantec in Dakar for a left painful red eye with decreased visual acuity lasting for 15 days. The patient did not receive any foreign body into the eye. Samples by corneal scraping were made for microbiological analysis and the patient was hospitalized and treated with a reinforced eye drops based treatment (ceftriaxone+gentamicin). The mycological diagnosis revealed the presence of a mold: F. oxysporum, which motivated the replacement of the initial treatment by eye drops containing iodized povidone solution at 1% because of the amphotericin B unavailability. Due to the threat of visual loss, oral fluconazole was added to the local treatment with eye drops povidone iodine. The outcome was favorable with a healing abscess and visual acuity amounted to 1/200th. Furthermore, we noted sequels such as pannus and pillowcase. The vulgarization of efficient topical antifungal in developing countries would be necessary to optimize fungal infection treatment.

Multidrug resistant Fusarium keratitis

CASE REPORT

We report a case of keratitis in a female contact lens wearer, who developed a deep corneal abscess. The culture of a corneal biopsy scraping was positive for multiresistant Fusarium solani. The patient has a complicated clinical course and failed to respond to local and systemic antifungal treatment, requiring eye enucleation.

CONCLUSION

Fusarium keratitis may progress to severe endophthalmitis. Clinical suspicion is paramount in order to start antifungal therapy without delay. Therapy is complex due to the high resistance of this organism to usual antifungal drugs.

Exogenous fungal endophthalmitis: an analysis of isolates and susceptibilities to antifungal agents over a 20-year period (1990-2010)

PURPOSE

To describe the isolates and susceptibilities to antifungal agents for patients with culture-proven exogenous fungal endophthalmitis.

DESIGN

Noncomparative case series.

METHODS

The clinical records of all patients treated for culture-proven exogenous fungal endophthalmitis at a university referral center from 1990 to 2010 were reviewed. Specimens initially used for diagnosis were recovered from the microbiology department and then underwent antifungal sensitivity analysis.

RESULTS

The antifungal susceptibilities of 47 fungal isolates from culture-positive fungal endophthalmitis are reported. Included are 14 isolates from yeast and 33 from mold. The mean (±standard deviation) minimum inhibitory concetrations (MICs) for amphotericin B (2.6 ± 3.5 μg/mL), fluconazole (36.9 ± 30.7 μg/mL), and voriconazole (1.9 ± 2.9 μg/mL) are reported. Presumed susceptibility to oral fluconazole, intravenous amphotericin B, intravitreal amphotericin B, oral voriconazole, and intravitreal voriconazole occurred in 34.8%-43.5%, 0-8.3%, 68.8%, 69.8%, and 100% of isolates, respectively.

CONCLUSIONS

Based on this laboratory study of isolates from exogenous fungal endophthalmitis, intravitreal voriconazole appears to provide the broadest spectrum of antifungal coverage and, as such, may be considered for empiric therapy of endophthalmitis caused by yeast or mold.

Epidemiological profile of fungal keratitis in Sfax (Tunisia)

Fungal keratitis is responsible for a significant burden of blinding disease in the developing world.

OBJECTIVE

The aim of this study was to determine the etiological agents, predisposing factors and therapy of keratomycosis in our region.

METHODS

Retrospective study of 60 patients with clinically and cultured confirmed fungi keratitis, who were attended at department of mycology in Sfax (1995 to 2012).

RESULTS

The mean age of patients was 47.2 years (sex ratio: 1.58). At least, one presumed predisposing factor was identified in 83.3% of cases. Corneal traumatism was established as the most common predisposing factor (61.6%) with vegetative matter (42.4%). Patients had corneal ulcer in 40% or abscess in 47.6%. All cases were positive on direct microscopy and 93% of cultures were positive. Filamentous fungi form the major etiologic agents (83%): Fusarium species (49% with F. solani [66%]), Aspergillus sp. (22%), Alternaria (5%), Scedosporium sp. (2%); and non-identified mold in (5%). Yeast were identified in 17% of cases. Topical agents were used in 97% of cases: ketoconazole 2%, amphotericin B (0.5%). Fluconazole per os was administrated for 11% of cases, itraconazole (2 cases) and voriconazole (one case). Keratoplasty was indicated for 27% of cases. The outcome was favorable in 16% of patients. Among the patients, 71% had persistent corneal deposit sequelae. Four patients lost the eyeball.

CONCLUSION

Corneal traumatism was the principal risk factor for fungal keratitis in young and middle-aged farmers. Fusarium solani is the predominant cause in Sfax. Early diagnosis, coupled with appropriate treatment, is crucial for increasing the chance of complete recovery.

Fungal endophthalmitis associated with compounded products

Fungal endophthalmitis is a rare but serious infection. In March 2012, several cases of probable and laboratory-confirmed fungal endophthalmitis occurring after invasive ocular procedures were reported nationwide. We identified 47 cases in 9 states: 21 patients had been exposed to the intraocular dye Brilliant Blue G (BBG) during retinal surgery, and the other 26 had received an intravitreal injection containing triamcinolone acetonide. Both drugs were produced by Franck's Compounding Lab (Ocala, FL, USA). Fusarium incarnatum-equiseti species complex mold was identified in specimens from BBG-exposed case-patients and an unopened BBG vial. Bipolaris hawaiiensis mold was identified in specimens from triamcinolone-exposed case-patients. Exposure to either product was the only factor associated with case status. Of 40 case-patients for whom data were available, 39 (98%) lost vision. These concurrent outbreaks, associated with 1 compounding pharmacy, resulted in a product recall. Ensuring safety and integrity of compounded medications is critical for preventing further outbreaks associated with compounded products.

In-vitro analysis of the microbicidal activity of 6 contact lens care solutions

BACKGROUND

Contact lens-related infections are often associated with inadequate contact lens hygiene, and therefore, contact lens care products should be able to sufficiently minimise the amount of pathogens that are responsible for these infections. In 2001, the EN ISO 14729 was introduced to ensure adequate disinfection efficacy of contact lens care solutions, but this norm has recently been criticised.

METHODS

In this study, six frequently used contact lens care solutions were retested according to the Stand Alone Test of the EN ISO 14729 (2001). The Stand Alone Test is a quantitative suspension test. In addition, the products were tested in a modified setting adding an organic load. The load was a mixture of human blood serum, lysozyme, and mucine, which resembles tear fluid.

RESULTS

The criteria of the Stand Alone Test recommended in EN ISO 14729 were only met by Aosept Plus. This 3% hydrogen-peroxide-based contact lens care solution attained a reduction factor of > 5 log units for bacteria and > 4 for fungi in all cases. Two further contact lens care solutions, Blue Vision and Optifree Replenish, met the criteria of a reduction factor of > 3 log units for bacteria and > 1 log unit for fungi, but only in the presence of artificial tear fluid. The three remaining products did not exhibit adequate disinfecting efficacy, at least against one of the tested microorganisms.

CONCLUSIONS

Through the observation that the artificial tear fluid used in this study influences the disinfecting efficacy of contact lens care solutions, especially that of multi-purpose solutions, in a different way than does albumin, mucine, or even the organic load suggested in EN ISO 14729, it becomes obvious that the test conditions in the EN ISO 14729 should be revised in order to create more realistic conditions, e.g., by using a more realistic artificial tear fluid. Furthermore, we suggest adapting the EN ISO 14729 to the European test hierarchy for chemical disinfectants and antiseptics, which consists of three test phases and also requests meeting stricter criteria in order to pass the test. Unless the test conditions guarantee a sufficient reduction of potential pathogens, the risk of contact lens-related microbial keratitis and other infections will remain for the users.

Infectious keratitis progressing to endophthalmitis: a 15-year study of microbiology, associated factors, and clinical outcomes

PURPOSE

To describe the incidence, microbiology, associated factors, and clinical outcomes of patients with infectious keratitis progressing to endophthalmitis.

DESIGN

Nonrandomized, retrospective, consecutive case series.

PARTICIPANTS

All patients treated for culture-proven keratitis and endophthalmitis between January 1, 1995 and December 31, 2009, at the Bascom Palmer Eye Institute.

METHODS

Ocular microbiology and medical records were reviewed on all patients with positive corneal and intraocular cultures over the period of the study. Univariate analysis was performed to obtain P values described in the study.

MAIN OUTCOME MEASURES

Microbial isolates, treatment strategies, and visual acuity (VA) outcomes.

RESULTS

A total of 9934 corneal cultures were performed for suspected infectious keratitis. Only 49 eyes (0.5%) progressed to culture-proven endophthalmitis. Fungi (n = 26) were the most common responsible organism followed by gram-positive bacteria (n = 13) and gram-negative bacteria (n = 10). Topical steroid use (37/49 [76%]) was the most common associated factor identified in the current study, followed by previous surgery (30/49 [61%]), corneal perforation (17/49 [35%]), dry eye (15/49 [31%]), relative immune compromise (10/49 [20%]), organic matter trauma (9/49 [18%]), and contact lens wear (3/49 [6%]). There were 27 patients in whom a primary infectious keratitis developed into endophthalmitis, and 22 patients in whom an infectious keratitis adjacent to a previous surgical wound progressed into endophthalmitis. Patients in the primary keratitis group were more likely to be male (22/27 [81%] vs 8/22 [36%]; P = 0.001), have history of organic matter trauma (8/27 [30%] vs 1/22 [5%]); P = 0.030), and have fungal etiology (21/27 [78%] vs 5/22 [23%]; P<0.001). Patients in the surgical wound-associated group were more likely to use topical steroids (20/22 [91%] vs 17/27 [63%]; P = 0.024). A VA of ≥ 20/50 was achieved in 7 of 49 patients (14%), but was <5/200 in 34 of 49 (69%) at last follow-up. Enucleation or evisceration was performed in 15 of 49 patients (31%).

CONCLUSIONS

Progression of infectious keratitis to endophthalmitis is relatively uncommon. The current study suggests that patients at higher risk for progression to endophthalmitis include patients using topical corticosteroids, patients with fungal keratitis, patients with corneal perforation, and patients with infectious keratitis developing adjacent to a previous surgical wound. Patients with sequential keratitis and endophthalmitis have generally poor visual outcomes.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Successful salvage therapy of Fusarium endophthalmitis secondary to keratitis: an interventional case series

Purpose

To describe a combination of treatment modalities used for the successful eradication of Fusarium endophthalmitis.

Design

Interventional case series.

Participants

Three consecutive patients with keratitis-associated Fusarium endophthalmitis.

Methods

After failure of traditional management options, a combination of intravitreal and long-term, high-dose systemic voriconazole, topical antifungal medications, and surgical intervention, with penetrating keratoplasty, lensectomy, and endoscopic-guided pars plana vitrectomy, was administered to each patient.

Results

All three cases achieved full resolution of the infection, with a final Snellen visual acuity score of 20/50 to 20/70.

Conclusions

An aggressive combination of therapeutic modalities, including the removal of subiris abscesses, might be needed for the successful resolution of Fusarium endophthalmitis.

Identification and sensitivity of two rare fungal species isolated from two patients with Fusarium keratomycosis

We report two cases of Fusarium keratomycosis in which molecular analysis was used to identify two rare causative Fusarium species. A 65-year-old woman was diagnosed with Fusarium keratomycosis caused by F. equiseti, confirmed by sequencing the internal transcribed spacer (ITS) region and morphological characteristics. She was initially treated with topical corticosteroid but the keratitis did not improve. Even after aggressive antifungal treatment, there was a severe reduction of vision. In the end, the eye perforated. Our second case was a 75-year-old man who had diabetes mellitus. He developed keratitis after his cornea was injured by corn stalks. The ITS region identified the causative organism as F. verticillioides. Unlike the first case, he had good visual recovery after early antifungal therapy. Our findings demonstrate that both ITS and morphological characteristics can be used to identify the exact Fusarium species causing Fusarium keratomycosis. This allowed us to determine the sensitivity of these species to antifungal drugs that can be used to treat patients with these species of Fusarium.

Endophthalmitis: Pathogenesis, clinical presentation, management, and perspectives

Endophthalmitis is a rare but sight-threatening complication that can occur after ocular surgery or trauma or as a consequence of systemic infection. To optimize visual outcome, early diagnosis and treatment are essential. Over recent decades, advances in hygienic standards, improved microbiologic and surgical techniques, development of powerful antimicrobial drugs, and the introduction of intravitreal antibiotic therapy have led to a decreased incidence and improved management of endophthalmitis. However, endophthalmitis still represents a serious clinical problem. This review focuses on current principles and techniques for evaluation and treatment of endophthalmitis. In addition, it addresses recent developments regarding antimicrobial treatment and prophylaxis of infectious endophthalmitis.