Impact of Contact Lens Group on Antifungal Efficacy of Multipurpose Disinfecting Contact Lens Solutions
ABSTRACT To evaluate and compare the in vitro effectiveness of multipurpose contact lens solutions (MPDS) to inhibit fungal colonization of Food and Drug Administration (FDA) contact lens groups.
Contact lenses from FDA groups I (low water content, nonionic), II (high water content, nonionic), III (low water content, ionic), and IV (high water content, ionic) were placed in sterile contact lens cases with 2 mL of ReNu MultiPlus, ReNu with MoistureLoc, or OPTI-FREE RepleniSH. Each contact lens-multipurpose solution combination was challenged with 0.1 mL of 10(6) colony-forming units/mL of Fusarium oxysporum and incubated at room temperature. Contact lenses and aliquots from phosphate-buffered saline rinse solutions, multipurpose solutions in cases, and lens cases were sampled at 24, 48, and 72 hours, plated on Sabouraud's agar, incubated at room temperature, and observed for growth (i.e., adhesion) for 1 to 7 days.
Used multipurpose contact lens solutions met or exceeded the 1-log reduction requirement of the FDA stand-alone test. Viable fungal colonies were recovered from group II lenses after 24 hours of storage in all three multipurpose solutions. Colonization was also detected with at least one contact lens-multipurpose solution pairing from groups I, III, and IV. Fungi were not recovered from lens-solution combinations after 24 hours or from phosphate-buffered saline solutions or lens cases at any period.
Antifungal activity of contaminated multipurpose solutions may be insufficient to prevent fungal colonization of contact lens materials despite meeting or exceeding the FDA stand-alone test criteria. Colonized lens may increase the risk of fungal keratitis.
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ABSTRACT: To investigate the relative abilities of different haplotypes of the Fusarium solani (FSSC)-Fusarium oxysporum (FOSC) complexes to attach to and invade hydrogel contact lenses. Silicone hydrogel and traditional hydroxyethylmethacrylate soft contact lenses were exposed to conidia [10 ml in phosphate-buffered saline (PBS)] of different haplotypes of fusaria associated with the Fusarium keratitis outbreak of 2004-2006. Select lenses and fungi were examined under conditions of organic enrichment. The lenses were incubated with shaking at ambient temperatures, then examined microscopically for the presence of penetration pegs (PPs). Attachment to and penetration of balafilcon A lenses in PBS within 96 hours were observed with representative isolates of FSSC 1-a, 1-b, and 2-d. Densities and coiled morphology of the PPs were similar. Eight of 8 FOSC failed to attach and form PP in PBS without prior sorption of organics by the lens. Generally, FSSC 1 isolates showed more rapid development of PP. Representatives of all haplotypes, including FSSC 2-c (ATCC 36031, a standard challenge strain), showed at least sparse attachment and penetration of the balafilcon A lens and, to a lesser degree, the lotrafilcon A lens. The development of PP in etafilcon A and galyfilcon A lenses required extended incubations (>21 days) relative to balafilcon A lenses. Attachment to and penetration of unworn hydrogel soft contact lenses by Fusarium varied with the strain and lens type rather than with the clinical, environmental, or geographic source of the isolates. Without organic enrichment of the lenses, penetration was more rapid and extensive by representatives of FSSC 1. Penetration was slow and less extensive under these conditions with FOSC and FSSC 2-c and 3. Organic enrichment of the lenses typically favored development of PP by the FOSC. Attachment and penetration of lenses occurred sooner and to a greater extent with surface-treated silicone hydrogel lenses than with the hydroxyethylmethacrylate lens.Cornea 06/2009; 28(4):447-50. DOI:10.1097/ICO.0b013e31818d33fb · 2.36 Impact Factor
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ABSTRACT: To determine the relative susceptibility of worn and unworn hydrogel contact lenses to penetration by hyphae of the Fusarium solani-Fusarium oxysporum species complex. Hydrogel contact lenses (lotrafilcon A, balafilcon A, senofilcon A, galyfilcon A, and etafilcon A) were removed from their original packages and placed directly on the eyes of 24 experienced contact lens wearers for 8-9 hours. Lenses were removed, each placed in 3.0 mL sterile phosphate buffered saline (PBS), and inoculated with 10 conidia of fusaria. Similar sets of unworn lenses were soaked in Sabouraud's dextrose broth for 2 hours prior to exposure to fusaria conidia in PBS. The entire surface of lenses was examined with microscopy for 14 days for the development of coiled hyphae in the lens matrix (ie, penetration pegs [PP]). A total of 21 of 54 worn hydrogel lenses representing 4 types of silicone hydrogel and one type of hydroxyethylmethacrylate lens were penetrated by the fusaria. Compared to unworn lenses, 9 of the 21 PP-positive worn lenses showed earlier and more extensive penetration than seen with the unworn lenses. Several worn lenses compared to their unworn counterparts showed negligible or delayed penetration. Worn hydrogel contact lenses without a history of exposure to disinfection solutions compared to unworn lenses of similar status may show enhanced or decreased susceptibilities to penetration by Fusarium. This suggests that tear characteristics are an additional factor in the invasive contamination of hydrogel contact lenses by Fusarium.Cornea 09/2009; 28(8):914-7. DOI:10.1097/ICO.0b013e31819c189d · 2.36 Impact Factor
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ABSTRACT: The purposes of this study were to describe 2 contact lens-associated Beauveria keratitis cases and to compare the isolates of 3 contact lens-associated Beauveria keratitis cases with Beauveria-based biopesticides using random amplification of polymorphic DNA (RAPD). A 55-year-old diabetic woman from New Mexico and a 31-year-old healthy woman from southern Wisconsin developed soft contact lens-related corneal ulcers unresponsive to topical moxifloxacin and prednisolone acetate drops. Their corneal cultures grew B. bassiana. These isolates, an isolate from a third soft contact lens-related Beauveria keratitis case, and Beauveria-based biopesticides sold in the United States were analyzed using morphological features, DNA sequencing, and RAPD. A PubMed, Cochrane Library, OVID, UpToDate, and Google search using the term "Beauveria" found only 9 reported Beauveria keratitis infections. Patient 1 responded to topical natamycin, ketoconazole, and 200 mg oral ketoconazole twice daily before developing a secondary bacterial infection requiring penetrating keratoplasty. After subsequent cataract surgery, the best-corrected visual acuity was 20/20. Patient 2 was treated with topical natamycin, topical amphotericin, and 200 mg oral voriconazole twice daily for 1 month with residual scarring and a best-corrected visual acuity of 20/25. RAPD showed that all isolates were unrelated. Although earlier reported Beauveria keratitis cases occurred after corneal injury in patients who did not wear contact lenses, 3 recent patients wore soft contact lenses and denied trauma, mirroring a changing trend in microbial keratitis. RAPD analysis showed that the Beauveria isolates were unrelated to one another and to Beauveria-based biopesticides. In Patient 2, oral voriconazole worked well.Cornea 12/2009; 29(2):152-8. DOI:10.1097/ICO.0b013e3181ae2575 · 2.36 Impact Factor