Attachment to and Penetration of Conventional and Silicone Hydrogel Contact Lenses by Fusarium solani and Ulocladium sp. In Vitro

Abstract

To our knowledge, this is the first report that F. solani produces coiled penetration pegs in the matrices of SH hydrophilic soft contact lenses similar in morphology to those found in HEMA lenses. F. solani attaches firmly to SH lenses and rarely penetrates the lens matrix, but viable fungal propagules may remain on the lens after vigorous rinsing with MPS. Failure to use a manual cleaning-disinfection procedure may help to explain the increased incidence of Fusarium keratitis associated with contact lens wear.

FusariumandCandida albicansBiofilms on Soft Contact Lenses: Model Development, Influence of Lens Type, and Susceptibility to Lens Care Solutions

“…In agreement with the results reported by these investigators, we also found, using both the industry standard ISO 14729 and XTT-based methods, that planktonic Fusarium and Candida cells were susceptible to lens disinfectants. The recent Fusarium keratitis outbreaks have been associated with loss of antimicrobial activity during contact lens storage, selective growth of Fusarium in globules of partially dried deposits of MoistureLoc, use of a "no-rub" procedure to care for contact lenses, a general decrease in effectiveness of MoistureLoc solution compared with other lens solutions, and binding of Fusarium to different contact lens materials (4,26). Our current findings suggest that the ability of Fusarium spp.…”

“…Similar to our findings, attachment to the lens surface ranged from a loose association of conidia and hyphae to firmly attached hyphae that were difficult or impossible to remove (4). It is noteworthy that Ahearn et al (4) reported that the two isolates of "F. solani" tested differed in their ability to attach to hydrogel contact lenses. Given that multilocus DNA sequence typing has shown that these isolates represent two phylogenetically distinct species within the FSSC (39) (GSU AFR4 [FSSC 1-b] and GSU 81036 [FSSC 4-a]), it is possible that some of the observed differences may be species or strain specific.…”

“…The loose association of Fusarium mats was recently observed in studies investigating the attachment and penetration of contact lenses (4). Ahearn et al (4) showed that Fusarium mats tended to be loosely associated with the lenses and could be released from the lenses by vigorous shaking or rinsing of the lens. Similar to our findings, attachment to the lens surface ranged from a loose association of conidia and hyphae to firmly attached hyphae that were difficult or impossible to remove (4).…”

Susceptibility of various corneal fungal isolates and Pseudomonas aeruginosa to contact lens disinfecting solutions

“…Indeed, it is possible that co-contamination of the lens case with P. aeruginosa and F. solani may decrease the antifungal activity of ReNu with MoistureLoc. Numerous researchers have attempted to explain the epidemic; causative factors hypothesized include direct uptake of alexidine by the contact lenses (thereby reducing its antimicrobial efficacy) [44], exposure of ReNu with MoistureLoc to prolonged temperature elevation [32], reduced antimicrobial activity of evaporated ReNu with MoistureLoc [45], enhanced growth of Fusarium spp on contact lens and lens case biofilm [46], direct penetration of Fusarium spp into soft contact lenses [47], and patient non-compliance with manufacturer's recommendations (e.g.. storing the lenses without emptying and replacing the solution in the case every day, just adding extra solution to the case, etc.) [14,45].…”

Evaluations of Shorter Exposures of Contact Lens Cleaning Solutions against Fusarium oxysporum Species Complex and Fusarium solani Species Complex To Simulate Inappropriate Usage

“…A number of laboratories have recently reported the findings of experimental studies seeking to account for the outbreak related to use of ML (1,7,11,13,14,18,19,27,34). Imamura et al concluded that the formation of biofilms on various types of contact lenses and the consequent reduced susceptibility to lens cleaning solutions played a role in the outbreak of Fusarium keratitis (14).…”