Fusarium Solani Keratitis Research Articles

Expression of Toll-Like Receptors in the Fusarium solani Infected Cornea

Purpose: To investigate the expression of toll-like receptors (TLRs) in the human cornea with Fusarium solani (F. solani) keratitis. Methods: Five human corneas with F. solani keratitis and 5 healthy human corneas were evaluated for TLR1–10 mRNA by reverse transcribed polymerase chain reaction (RT-PCR) and relative real-time PCR. The proteins of TLR2, 4, and 9 were also compared by Western blot. The mean times between these corneas were collected, and the onset of treatment to surgery was 34.4 ± 12.4 days, ranging from 15 to 47 days. The data were analyzed with SPSS15.0. Results: TLR1–10 mRNA was expressed in both healthy and F. solani infected human corneas. The expression of TLR2, 4, 6, and 9 mRNA in the F. solani infected human corneas were upregulated. The Western blot showed the protein expression of TLR2, 4, and 9 was also upregulated in the corneas with F. solani keratitis than that of the healthy corneas. Conclusions: TLRs are expressed diversely in the F. solani infected human cornea, and TLR2, 4, and 9 may be implicated in the pathogenesis of F. solani infection in the cornea.

Nécrose du segment antérieur sur kératomycose à Fusarium polyrésistant : À propos d’un cas

Keratomycosis is a rare sight-threatening infection of the cornea, with greater morbidity than bacterial keratitis. Predisposing factors in its pathogenesis are corneal trauma, mostly of plant origin, and overuse of topical corticosteroids, associated or not with antibiotics. We report a case of a 71-year-old man who developed Fusarium (lichenicola or solani) keratitis, 15 days after beginning topical therapy with a corticosteroid and antibiotic. Despite aggressive antifungal therapy with fluconazole, he required a penetrating keratoplasty for impending corneal perforation, and finally, even after systemic use of itraconazole and topical use of amphotericin B, the infection progressed and an evisceration was required. In the evisceration material, a multidrug-resistant Fusarium lichenicola or solani, was found, partially sensitive to voriconazole only.

Clinical experience in managing Fusarium solani keratitis

Fusarium solani keratitis is a rare ocular infectious disease. The clinical characteristics and treatment methods of 18 patients with culture proven F. solani keratitis between July 1997 and December 2003 and with a follow-up period of more than 4 months were analysed retrospectively. The patients were divided into two groups based on the severity of keratitis. Group A (n = 13) displayed non-severe keratitis and were treated with debridement, lamellar keratectomy and antifungal medication. Group B (n = 5) displayed severe keratomycosis and were treated with lamellar keratectomy combined with amniotic membrane transplantation (AMT) and antifungal medication. In group A, wound healing did not interfere with the integrity of the anterior chamber. The mean re-epithelialisation time was 12.67 days (range: 5-21 days). All patients were free of major immediate postoperative complications. In group B, AMT preserved the anterior chamber integrity in two cases, but failed to do so in the other three cases. Therapeutic patch grafts were required in these three cases. Non-severe F. solani keratitis is best treated with superficial keratectomy. Timely AMT combined with lamellar keratectomy appears to be an adjuvant therapy for severe keratomycosis and avoiding emergent therapeutic penetrating keratoplasty. However, AMT was effective in cases involving non-suppurative Fusarium keratitis.

EP005 Influence of Caspofungin on blocking Candida adherence to epithelial cells in a thrush model

Fungal keratitis is a common disease that causes blindness. An effective animal model for fungal keratitis is essential for advancing research on this disease. Our objective is to develop a novel mouse model of Fusarium solani keratitis through the inoculation of fluorescent-labeled fungi into the cornea to facilitate the accurate and early identification and screening of fungal infections. F. solani was used as the model fungus in this study. In in vitro experiment, the effects of Calcofluor White (CFW) staining concentration and duration on the fluorescence intensity of F. solani were determined through the mean fluorescence intensity (MFI); the effects of CFW staining on the growth of F. solani were determined by the colony diameter. In in vivo experiment, the F. solani keratitis mice were induced and divided into a CFW-unlabeled and CFW-labeled groups. The positive rate, corneal lesion score and several positive rate determination methods were measured. The MFIs of F. solani in the 30 μg/ml CFW-30 min, 90 μg/ml CFW-10 min and 90 μg/ml CFW-30 min groups were higher than that in the 10 μg/ml CFW-10 min group (P < 0.01). Compared with the 30 μg/ml CFW-30 min group, only the 90 μg/ml CFW-30 min group showed higher MFI (P < 0.05). No significant difference was observed in the colony diameter in the CFW unstained group compared with that in the 10, 30, 90, 270, or 810 μg/ml CFW groups stained for either 10 or 30 min (P > 0.05). No significant differences (P > 0.05) were observed for the positive rate or the corneal lesion scores between the CFW-unlabeled and the CFW-labeled group. On day 1 and 2, the positive rates of the infected corneas in the scraping group were lower than those in the fluorescence microscopy group (P < 0.05). On day 3, these observe methods showed no significant difference (P > 0.05). Thus, these experiments established a novel murine model of F. solani keratitis utilizing fluorescent labeled fungi. This model facilitates the accurate identification and screening of fungal infections during the early stages of fungal keratitis and provides a novel and reliable technology to study the fungal keratitis.

Non‐ulcerative fungal keratitis diagnosed by posterior lamellar biopsy*

We report a case of Fusarium solani keratitis which highlights the difficulties often associated with management of fungal corneal infections. This case demonstrates several unusual and interesting features: the occurrence of deep fungal pathology after superficial injury, the difficulties encountered in attempting to isolate and identify the causative organism, and the protracted course taken by an organism often noted to be rapidly destructive. These features necessitated an individual approach to therapy, employing unconventional medical and surgical techniques to achieve a satisfactory outcome.

Invasion and survival ofFusarium solaniin the dexamethasone-treated cornea of rabbits

Electron microscopic observations, as well as in vitro experiments, on experimental Fusarium solani keratitis of rabbits were performed to study the mode of fungal invasion into the corneal stroma, the interactions between F. solani and inflammatory cells under the influence of topical dexamethasone (DXM) treatment, and the survival mechanism of the fungi in the DXM-treated cornea. Electron microscopy showed that, while the fungus invaded into the corneal stroma, digestion of collagen fibrils occurred around the hyphae, where amorphous material was often noted. In DXM-nontreated cornea, the fungal hyphae were entrapped by pseudopodia of the neutrophils and destruction of the hyphae was noted on day 3 of infection, most hyphae having disappeared by day 7. In the DXM-treated cornea, however, neutrophils could not ingest and destroy the hyphae. In qualitative nitroblue tetrazolium (NBT)-reduction tests using rabbit peripheral blood neutrophils, DXM significantly suppressed the rate of NBT-reduction and the rate of adherence to the fungal microconidia. In the DXM-treated corneal lesions, a considerable increase in both number and size of fungal peroxisomes was noted. Furthermore, the hyphae, surrounded by neutrophils, showed double or triple cell wall formation or sometimes a hypha-in-hypha structure. Similar hypha-in-hypha structures were also observed when the organisms were treated in vitro with a fungistatic concentration of H2O2. We suggest that this special structure is a protective device produced for the survival of F. solani when subject to neutrophil attack in the DXM-treated cornea.