Hyphal Penetration of Worn Hydrogel Contact Lenses by Fusarium

Dematiaceous fungal invasion of a bandage contact lens

A 61-year-old man presented with a 1-month history of reduced vision, redness and pain in the right eye. Examination revealed a bandage contact lens (BCL) in situ with diffuse, pigmented deposits. On removal, the underlying cornea was found to be clear. He had been prescribed the BCL 6 months ago following a deep-seated corneal foreign body removal and was unable to follow-up subsequently.The BCL was sent for microbiological and histopathological evaluation. The culture revealed growth of Cladosporium spp, a dematiaceous fungi. Periodic acid-Schiff staining revealed infiltration of pigmented fungal filaments into the substance of the BCL.While contact lens deposits are a frequent finding, fungal deposits are seldom noted. Irregular follow-up and improper lens maintenance are significant risk factors for the same. Early identification and subsequent removal of the lens is vital to prevent infection of the underlying ocular structures.

Invasion of the therapeutic contact lens by a rare fungal species presenting as the acute red eye: A case report

Therapeutic contact lens used in the treatment of non-infective corneal pathologies are prone to infection by microorganisms like bacteria, protozoa and fungi. Bacteria cause the majority of contact lens-related infections. Although rare, fungal invasion of soft contact lenses is a potentially severe complication which may cause keratitis and more fulminating infections. Contact lens invasion can present as acute red eye warranting its replacement to prevent the development of keratitis. Different genera and species of fungi are documented to cause contact lens invasion. We report a rare case of fungal invasion of the contact lens by Aspergillus nidulans.

Demonstration of Adventitious Sporulation in Fusarium Petroliphilum Onychomycosis

Fusarium petroliphilum is a recently described species within the Fusarium solani species complex. Some strains of Fusarium species are capable of forming yeast-like structures in tissue as well as in culture through a process known as "adventitious sporulation." Here, we describe the formation of these yeast-like reproductive structures in infected nail tissue obtained from a case of onychomycosis. These structures were also observed in culture grown on RPMI 1640 agar supplemented with 2% glucose. The isolate was resistant to azoles and echinocandins. To the best of our knowledge, this is the first report describing adventitious sporulation in F. petroliphilum and its etiologic role in onychomycosis.

Microbial adhesion to silicone hydrogel lenses: a review

PURPOSE

Microbial adhesion to contact lenses is believed to be one of the initiating events in the formation of many corneal infiltrative events, including microbial keratitis, that occur during contact lens wear. The advent of silicone hydrogel lenses has not reduced the incidence of these events. This may partly be related to the ability of microbes to adhere to these lenses. The aim of this study was to review the published literature on microbial adhesion to contact lenses, focusing on adhesion to silicone hydrogel lenses.

METHODS

The literature on microbial adhesion to contact lenses was searched, along with associated literature on adverse events that occur during contact lens wear. Particular reference was paid to the years 1995 through 2012 because this encompasses the time when the first clinical trials of silicone hydrogel lenses were reported, and their commercial availability and the publication of epidemiology studies on adverse events were studied.

RESULTS

In vitro studies of bacterial adhesion to unworn silicone hydrogel lens have shown that generally, bacteria adhere to these lenses in greater numbers than to the hydroxyethyl methacrylate-based soft lenses. Lens wear has different effects on microbial adhesion, and this is dependent on the type of lens and microbial species/genera that is studied. Biofilms that can be formed on any lens type tend to protect the bacteria and fungi from the effects on disinfectants. Fungal hyphae can penetrate the surface of most types of lenses. Acanthamoeba adhere in greater numbers to first-generation silicone hydrogel lenses compared with the second-generation or hydroxyethyl methacrylate-based soft lenses.

CONCLUSION

Microbial adhesion to silicone hydrogel lenses occurs and is associated with the production of corneal infiltrative events during lens wear.

Phylogenetic relationships among members of the Fusarium solani species complex in human infections and the descriptions of F. keratoplasticum sp. nov. and F. petroliphilum stat. nov

Fusarium species are frequently associated with mycotic keratitis and, to a lesser extent, cases of localized and disseminated infections. The Fusarium solani species complex (FSSC) is the most common group of fusaria associated with human infectious diseases. Several studies to date have revealed dozens of strongly supported phylogenetic species within this important evolutionary clade, though little work has been done to improve the taxonomy and understanding of the reproductive mode and phenotypes of the predominant clinically relevant species. Here we described Fusarium keratoplasticum sp. nov., and Fusarium petroliphilum stat. nov., two phylogenetic species that are among the most frequently isolated fusaria in plumbing drain biofilms and outbreaks of contact lens-associated mycotic keratitis. F. keratoplasticum isolates were highly variable and showed a range of morphological characteristics typical for most classical concepts of 'F. solani.' Many isolates failed to produce sporodochia and macroconidia. Although most attempts to sexually cross F. keratoplasticum isolates failed, a heterothallic sexual stage typical for the FSSC was discovered by pairing isolates of opposite mating type on V-8 agar, the ascospores of which showed molecular evidence of recombination. Secondary metabolite profiles of FSSC species defined through molecular data were compared for the first time and revealed the production of bioactive compounds including cyclosporines and several novel compounds of unknown function. We speculate that the inferred phenotypic variability in these species is the result of the almost entirely anthropogenic sources from which they are derived, including biofilms on plumbing systems.