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Peer-reviewed articles

2016

Liu,L. Y., Seo,J., McCanna,D. J., Subbaraman,L. N., Jones,L. W. Assessment of biofilm formation of E. meningoseptica, D. acidovorans, and S. maltophilia in lens cases and their growth on recovery media. Contact Lens and Anterior Eye 2016;39,2:117-123. [ Show Abstract ]

Purpose: Bacterial biofilm formation in contact lens cases is a risk factor in the development of both microbial and infiltrative keratitis. This investigation evaluated three emerging pathogens: Stenotrophomonas maltophilia, Elizabethkingia meningoseptica, and Delftia acidovorans for biofilm formation and metabolic activity in lens cases. Also, growth of these bacteria on different media was assessed to optimize recovery conditions. Methods: The three bacteria were incubated in lens cases with different concentrations of tryptic soy broth. Biofilm formation was evaluated by measuring metabolic activity using MTT and enumerating the number of viable bacteria. To determine the optimal recovery media, dilutions of these microorganisms were plated on six different media. The number of colony forming units (CFU) was recorded after 48, 72, and 96 h of incubation at 32 °C and 37 °C for S. maltophilia, and at 37 °C for E. meningoseptica and D. acidovorans. Results: All three microorganisms established biofilms in the lens cases, with significant numbers of CFU recovered. Biofilms of S. maltophilia and E. meningoseptica were metabolically active. Significant reduction in metabolic activity and number of viable S. maltophilia occurred when the incubation temperature was raised from 32 °C to 37 °C (p < 0.05). The metabolic activity of the biofilms increased with greater organic load present. The highest percent recovery for all three organisms was given by Columbia blood agar, followed by chocolate. Conclusion: Based on the results, the presence of the three emerging pathogens present in lens cases and from corneal isolates can be accurately determined if proper growth media and incubation temperatures are utilized.

Dantam,J., McCanna,D. J., Subbaraman,L. N., Papinski,D., Lakkis,C., Mirza,A., Berntsen,D. A., Morgan,P., Nichols,J. J., Jones,L. W., Mathew,J. H., Cox,S. M., Bickle,K. M., Powell,D. R., Cox,J., Miller,W. L., Wallace-Tucker,A., Charrier,S., Chen,Y. -J, Cardenas,L., Huerta,S., Dionne,K., Maldonado-Codina,C., Plowright,A. J., Howarth,G. F., Chatterjee,N., Smith,S., Dumbleton,K., Schulze,M., Moezzi,A., Luensmann,D., Ngo,W., Paquette,L., Srinivasan,S., Varikooty,J., Johnson,J., Simpson,M., Voss,L., R Microbial contamination of contact lens storage cases during daily wear use. Optometry and Vision Science 2016;93,8:925-932. [ Show Abstract ]

Purpose. To evaluate contact lens (CL) storage case contamination when used with four different CL care solutions during daily wear of three different CL materials. Methods. A parallel, prospective, bilateral, randomized clinical trial (n = 38) was conducted. Subjects were randomly assigned to use one of three CL materials (etafilcon A, senofilcon A, or galyfilcon A) on a daily wear basis. Subsequently, each subject randomly used one of four different CL care solutions (Biotrue, OPTI-FREE PureMoist, RevitaLens OcuTec, and CLEAR CARE) for 2 weeks, along with their respective storage cases. After every 2-week period, their storage cases were collected and the right and left wells of each storage case were randomized for two procedures: (1) microbial enumeration by swabbing the storage case surface and (2) evaluation of biofilm formation (multipurpose solution cases only) using a crystal violet staining assay. Results. More than 80% of storage cases were contaminated when used in conjunction with the four CL care solutions, irrespective of the CL material worn. Storage cases maintained with CLEAR CARE (mean Log colony forming units (CFU)/ well ± SD, 2.0 ± 1.0) revealed significantly (p < 0.001) greater levels of contamination, compared to those maintained with Biotrue (1.3 ± 0.8) and RevitaLens OcuTec (1.2 ± 0.8). Predominantly, storage cases were contaminated with Gram-positive bacteria (= 80%). There were significant differences (p = 0.013) for the levels of Gram-negative bacteria recovered from the storage cases maintained with different CL care solutions. Storage cases maintained withOPTI-FREE PureMoist (0.526 ± 0.629) showed significantly higher biofilm formation (p = 0.028) compared to those maintained with Biotrue (0.263 ± 0.197). Conclusions. Levels of contamination ranged from 0 to 6.4 Log CFU/storage case well, which varied significantly (p < 0.001) between different CL care solutions, and storage case contamination was not modulated by CL materials. © Copyright 2016 American Academy of Optometry.

Phan,C. -M, Bajgrowicz,M., McCanna,D. J., Subbaraman,L. N., Jones,L. Effects of Antifungal Soaked Silicone Hydrogel Contact Lenses on Candida albicans in an Agar Eye Model. Eye and Contact Lens 2016;42,5:313-317. [ Show Abstract ]

Purpose: To evaluate the effects of two commercial silicone hydrogel contact lenses (CLs) soaked with natamycin (NA) or fluconazole (FL) on the growth of Candida albicans in an in vitro eye model. Methods: Three-D printed molds were used as a cast for making eye-shaped models comprising potato dextrose agar. Senofilcon A (SA) and lotrafilcon B (LB) CLs were incubated with either 2 mL of NA or FL at a concentration of 1 mg/mL for 24 hr. To simulate a fungal infection, the eye models were coated with C. albicans. The drug-soaked lenses were placed on top of the eye models. Seven experimental conditions were examined: (1) NA-SA, (2) NA-LB, (3) FL-SA, (4) FL-LB, (5) SA, (6) LB, and (7) control - no lens. At specified time points (t1, 8, 16, 24, 48 hr), the agar eyes from each experimental condition were removed from the incubator and photographed. The yeast cells from the 24 and 48 hr time point were also analyzed using light microscopy. Results: At 24 and 48 hr, there was considerable growth observed for all conditions except for the NA-SA and NA-LB conditions. When observed under the microscope at 24 and 48 hr, the morphology of the yeast cells in the FL-SA and SA condition were similar to that of the control (oval shaped). There was limited hyphae growth observed for LB and significant visible hyphae growth for the NA-LB group. For NA-SA, NA-LB, and FL-LB groups, the cells were significantly smaller compared with the control. Conclusions: For NA-SA and NA-LB, there was limited growth of C. albicans observed on the eye models even after 48 hr. Under the microscope, the cell morphology differ noticeably between each testing condition, and is dependent on drug-lens combinations. © 2015 Contact Lens Association of Ophthalmologists.

2015

Chang,J. M. L., McCanna,D. J., Subbaraman,L. N., Jones,L. W. Efficacy of antimicrobials against biofilms of achromobacter and pseudomonas. Optometry and Vision Science 2015;92,4:506-513. [ Show Abstract ]

Purpose. Achromobacter xylosoxidans and Pseudomonas aeruginosa biofilms can develop in ophthalmic products and accessories such as contact lens cases, leading to the development of ocular infections. This study evaluated the efficacy of the antimicrobials polyaminopropyl biguanide (PAPB) and benzalkonium chloride (BAK) against A. xylosoxidans and P. aeruginosa biofilms. Methods. Biofilms of A. xylosoxidans and P. aeruginosa used as a comparative control were formed by incubating the bacteria on contact lens cases and on coverslips in phosphate-buffered saline. The biofilms were then exposed to PAPB and BAK for 5 minutes and 4 hours. After exposure, alginate swabs were used to remove the biofilms from the lens cases and the bacteria were plated on tryptic soy agar for determination of survivors. Also, after exposure to these disinfectants, the A. xylosoxidans and P. aeruginosa biofilms were stained with SYTO 9 and propidium iodide. Using a confocal microscope with a 488-nm laser, the number of cells with damaged cell membranes was determined. Results. After 5 minutes of exposure to BAK or PAPB, A. xylosoxidans biofilms were more resistant to the antimicrobial effects of these disinfectants than P. aeruginosa biofilms. After 4 hours, both organisms were reduced by more than 3 logs after exposure to either BAK or PAPB. Confocal microscopy studies revealed that BAK was more effective at damaging A. xylosoxidans and P. aeruginosa cell membranes than PAPB at the concentrations used in ophthalmic products. Conclusions. Biofilms of the emerging pathogen A. xylosoxidans were more resistant to the disinfectants PAPB and BAK than biofilms of P. aeruginosa. Because of the emergence of A. xylosoxidans and the demonstrated greater resistance to the common ophthalmic preservatives BAK and PAPB than the standard Gram-negative organism P. aeruginosa, A. xylosoxidans biofilms should be assessed in antimicrobial challenge tests to assure the safety of multiuse ophthalmic products. Copyright © 2015 American Academy of Optometry.

2014

Gorbet,M., Peterson,R., McCanna,D., Woods,C., Jones,L., Fonn,D. Human corneal epithelial cell shedding and fluorescein staining in response to silicone hydrogel lenses and contact lens disinfecting solutions. Current eye research 2014;39,3:245-256. [ Show Abstract ]

Purpose: A pilot study was conducted to evaluate human corneal epithelial cell shedding in response to wearing a silicone hydrogel contact lens/solution combination inducing corneal staining. The nature of ex vivo collected cells staining with fluorescein was also examined. Methods: A contralateral eye study was conducted in which up to eight participants were unilaterally exposed to a multipurpose contact lens solution/silicone hydrogel lens combination previously shown to induce corneal staining (renu® fresh™ and balafilcon A; test eye), with the other eye using a combination of balafilcon A soaked in a hydrogen peroxide care system (Clear Care®; control eye). Lenses were worn for 2, 4 or 6 hours. Corneal staining was graded after lens removal. The Ocular Surface Cell Collection Apparatus was used to collect cells from the cornea and the contact lens. Results: In the test eye, maximum solution-induced corneal staining (SICS) was observed after 2 hours of lens wear (reducing significantly by 4 hours; p < 0.001). There were significantly more cells collected from the test eye after 4 hours of lens wear when compared to the control eye and the collection from the test eye after 2 hours (for both; n = 5; p < 0.001). The total cell yield at 4 hours was 813 ± 333 and 455 ± 218 for the test and control eyes, respectively (N = 5, triplicate, p = 0.003). A number of cells were observed to have taken up the fluorescein dye from the initial fluorescein instillation. Confocal microscopy of fluorescein-stained cells revealed that fluorescein was present throughout the cell cytoplasm and was retained in the cells for many hours after recovery from the corneal surface. Conclusion: This pilot study indicates that increased epithelial cell shedding was associated with a lens-solution combination which induces SICS. Our data provides insight into the transient nature of the SICS reaction and the nature of fluorescein staining observed in SICS. © 2014 Informa Healthcare USA, Inc.

Hall,B., McCanna,D., Jones,L. Identification of coagulase-negative staphylococci in daily disposable contact lens wearers. Letters in applied microbiology 2014;59,3:313-319. [ Show Abstract ]

This study aimed to identify and quantify the number of contaminating organisms on daily disposable (DD) soft contact lenses, which may be responsible for mild cases of keratitis that occur with this lens wear modality. Ten participants wore DD lenses, and 10 participants wore planned replacement (PR) lenses. Lenses were collected aseptically and analysed for microbial contamination. Colony-forming units (CFU) were recorded, and representative colonies were used for identification using the API identification system. The DD lenses evaluated in this study were contaminated with coagulase-negative staphylococcus (CNS), ranging from 1 to 653 CFU. PR lenses showed more diversity in the types of contaminating micro-organisms and consisted of CNS, Gram-negative bacteria (Pseudomonas), a yeast (Candida) and a mould (Aspergillus), ranging from 1 to 230 CFU. CNS was the only type of micro-organism found on DD contact lenses and therefore may be the cause of any form of keratitis observed in DD lens wearers. © 2014 The Society for Applied Microbiology.

2011

Youn,H. -Y, McCanna,D. J., Sivak,J. G., Jones,L. W. In vitro ultraviolet-induced damage in human corneal, lens, and retinal pigment epithelial cells. Molecular Vision 2011;17237-246.

Kao,E. C. Y., McCanna,D. J., Jones,L. W. Utilization of in vitro methods to determine the biocompatibility of intraocular lens materials. Toxicology in Vitro 2011;25,8:1906-1911.

Abstracts

2015

McCanna D, Oh S, Seo J, Subbaraman L, Coles-Brennan C, Fadli Z, Jones L. Effect of Denatured Lysozyme on Human Corneal Epithelial Cells. Invest Ophthalmol Vis Sci 2015;56: E-abstract 3511. [ PDF ]

Subbaraman L, McCanna D, Oh S, Ng A, Coles-Brennan C, Fadli Z, Jones L. Lysozyme activity on contact lenses and the impact of denatured lysozyme on human corneal epithelial cells. BCLA Clinical Conference and Exhibition, 2015. [ PDF ]

McCanna D, Oh S, Seo J, Coles_brennan C, Fadli Z, Subbaraman L. In vitro evaluation of the effect of lysozyme coated contact lenses on cell viability and inflammatory response. BCLA Clinical Conference and Exhibition, 2015. [ PDF ]

Subbaraman L, Heynen M, McCanna D, Omali N, Jansen M, Fadli Z, Toubouti Y, Coles-Brennan C, Jones L . Impact of pigment presence in etafilcon A on in vitro interaction of lysozyme and impact on inflammatory biomarker release. Optom Vis Sci 2015;92: E-abstract 150097.

2014

McCanna D,Liu L, Seo J, Subbaraman L, Jones L. Assessment of the growth of Stenotrophomonas maltophilia, Elizabethkingia meningoseptica and Delftia acidovorans in contact lens cases and on recovery media. Invest Ophthalmol Vis Sci 2014;55: E-abstract 6051.

Dantam, McCanna D, Subbaraman L, Lakkis C, Morgan P, Nichols J, Jones L. 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: E-abstract 4675. [ PDF ]

Subbaraman L, McCanna D, Lorentz H, Soong F, Salapatek A, Jones L. Tear Cytokines in Non-Dry Eye and Dry Eye Participants After Exposure to a Low Humidity Environmental Exposure Chamber. Invest Ophthalmol Vis Sci 2014;55: E-abstract 3682.

Jones L, Dantam J, McCanna D, Subbaraman L, Morgan P, Nichols J, Lakkis C. Impact of different contact lens care solutions and lens materials on contact lens storage case contamination. BCLA Clinical Conference and Exhibition, 2014. [ PDF ]

Lorentz H, McCanna D, Subbaraman L, Jones L, Salapatek A, Soong F. Changes in cytokine expression for dry eye and non dry eye subjects exposed to a low humidity environmental exposure chamber. Optom Vis Sci 2014;91: E-abstract 140106.

2013

McCanna D, Jones L. The effect of contact lens solutions on membrane permeability of Staphylococcus aureus aggregates. Contact Lens & Anterior Eye 2013;36,S2:e40-e41.

McCanna D, Chang J, Subbaraman L, Jones L. Efficacy of contact lens solutions against Achromobacter xylosoxidans biofilms using confocal microscopy. Canadian Optometry Schools Research Conference, Waterloo, Canada, 2013.

McCanna D, Jones L. Membrane permeability of staphylococcus aureus aggregates exposed to contact lens care solutions. Canadian Optometry Schools Research Conference, Waterloo, Canada, 2013.

Subbaraman L, Thangavelu M, McCanna D, Jones L. Tear film cytokine analyses using a novel electrochemiluminescent array technique. Canadian Optometry Schools Research Conference, Waterloo, Canada, 2013.

Subbaraman L, Thangavelu M, McCanna D, Jones L. Quantification of lipocalin-1 in tears and contact lens deposits using a sandwich elisa technique. Canadian Optometry Schools Research Conference, Waterloo, Canada, 2013.

Subbaraman L, Thangavelu M, McCanna D, Jones L. Quantifying tear film inflammatory markers using a novel, multiplex electrochemiluminescent technique. Tear Film & Ocular Surface International Conference, Sicily, Italy, 2013.

McCanna D, Jones L. Membrane permeability of staphylococcus aureus aggregates exposed to contact lens care solutions. Tear Film & Ocular Surface International Conference, Sicily, Italy, 2013.

McCanna D, Chang J, Subbaraman L, Jones L. Efficacy of contact lens solutions against Achromobacter xylosoxidans biofilms using confocal microscopy. Tear Film & Ocular Surface International Conference, Sicily, Italy, 2013.

McCanna D, Chang J, Subbaraman L, Jones L. Efficacy of contact lens solutions against Achromobacter xylosoxidans biofilms using confocal microscopy. Invest Ophthalmol Vis Sci 2013;54: EAbstract 523.

Subbaraman L, Thangavelu M, McCanna D, Jones L. Tear film cytokine analyses using a novel electrochemiluminescent array technique. Invest Ophthalmol Vis Sci 2013;54: E-Abstract 4325.

2012

McCanna D, Jones L. Membrane Permeability Of Staphylococcus Aureus Aggregates Exposed To Contact Lens Care Solutions. Invest Ophthalmol Vis Sci 2012;53:ARVO E-Abstract 6089.

Situ P, McCanna D, Gorbet M, Jones L. Confocal Imaging Of Hyper-reflective Corneal Epithelial Cells During And After Contact Lens Wear . Invest Ophthalmol Vis Sci 2012;53:ARVO E-Abstract 4698.

2011

Kao E, McCanna D, Jones L. In vitro model for determining the viability and strength of adhesion of human lens epithelial cells to silicone. NSERC 2020 Network Meeting (Orllia, Ontario), 2011.

McCanna D, Mikkelsen S, Rahimi M, So F, Zhou Y, Sivak J, Jones L. Determining toxicity thresholds in ocular in vitro test batteries using benzalkonium chloride. International Society for Contact Lens Research (Napa Valley, California), 2011.

Professional Publications

2015

McCanna D. Being “SunSmart”: Finding the right life-light balance. ContactLensUpdate.com 2015.

2012

McCanna D. How safe is your lens case?. ContactLensUpdate.com 2012.