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Jaya Dantam, David J McCanna, Lakshman N Subbaraman, Carol Lakkis, Philip B Morgan, Jason J Nichols, Lyndon William Jones; Microbial contamination of contact lens storage cases with the use of different contact lens care solutions and lens materials. Invest. Ophthalmol. Vis. Sci. 2014;55(13):4675.
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To evaluate contact lens (CL) storage case contamination when used with 3 multi-purpose disinfecting solutions and a peroxide-based solution during daily wear of 3 different CL materials.
A prospective, bilateral and randomized clinical trial, comprising 34 subjects was conducted. The subjects were randomly assigned to use 1 of the 3 CL materials (etafilcon A, senofilcon A and galyfilcon A) on a daily wear basis. Subsequently, each subject randomly used 1of the 4 different CL care solutions (A-polyaminopropyl biguanide+polyquaternium; B-POLYQUAD+Aldox; C- alexidine+polyquaternium-1 and D-hydrogen peroxide) for 2 weeks, along with the respective storage cases. After every 2 week period, the storage cases were collected and processed to evaluate microbial growth. The right and left wells of each storage case were randomized for 2 procedures: (i) microbial enumeration and (ii) evaluation of biofilm formation. For microbial recovery, the surface of each storage case was swabbed and plated, and biofilm formation was assessed using a crystal violet staining assay.
More than 75% of the storage cases were contaminated when used in conjunction with the 4 CL care solutions, irrespective of the CL material. The highest rate of storage case contamination was found with solution B (97%), while the lowest was with solution C (79%). Statistical analysis revealed significantly (p≤0.01) lower levels of contamination in the storage cases maintained with solution A (mean Log CFU/ well±SD, 1.35±0.82) and C (1.39±0.91) when compared to D (2.1±1.01). Predominantly, all the storage cases were contaminated with Gram-positive bacteria (≥ 80%). Within the different CL care solutions, the use of solution D revealed significantly (p≤0.001) higher recovery of Gram-positive bacteria (2.08±0.99) from the storage cases when compared to A (1.31±0.78) and C (1.20±0.77). Storage cases maintained with solution B (16%) showed higher recovery of Gram-negative bacteria, when compared to A (3%), C (8%) and D (None), however there was no statistically significant difference. Storage cases maintained with solution A (range of absorbance, 0.059-1.121) showed significantly (p≤0.03) lower biofilm formation when compared to B (0.092-3.669).
The current study shows that microbial contamination of storage cases varies with the use of different formulations of CL care solutions.
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