Contact Lens Disinfection Research Articles

Resistance and growth of Fusarium spp. in contact lens disinfectant solutions

Purpose: Fusarium spp. can cause fungal keratitis in contact lens wearers and an outbreak of infection was associated with use of a multipurpose disinfectant solution (MPS). Here, the efficacy of contact lens care solutions against Fusarium strains was investigated.

Optifree puremoist contact lens disinfecting solution vs blister pack: objective and subjective evaluation

Optifree puremoist contact lens disinfecting solution vs blister pack: objective and subjective evaluation

Cytotoxic and inflammatory effects of contact lens multipurpose solutions on human corneal epithelial cells

Purpose: Clinical data show that contact lens (CL) multipurpose solutions (MPS) may cause damage to the ocular surface. This study examined the cytotoxic and inflammatory effects of CL MPS and hydrogen peroxide CL disinfection systems (HPCLDS) on cultured human corneal epithelial (HCE) cells.

Systemic allergic dermatitis of the lips resulting from allergy to an antimicrobial agent in a contact lens disinfecting solution

Systemic allergic dermatitis of the lips resulting from allergy to an antimicrobial agent in a contact lens disinfecting solution

Acanthamoeba keratitis: The Persistence of Cases Following a Multistate Outbreak

Purpose: To describe the trend of Acanthamoeba keratitis case reports following an outbreak and the recall of a multipurpose contact lens disinfection solution. Acanthamoeba keratitis is a serious eye infection caused by the free-living amoeba Acanthamoeba that primarily affects contact lens users.Methods: A convenience sample of 13 ophthalmology centers and laboratories in the USA, provided annual numbers of Acanthamoeba keratitis cases diagnosed between 1999–2009 and monthly numbers of cases diagnosed between 2007–2009. Data on ophthalmic preparations of anti-Acanthamoeba therapies were collected from a national compounding pharmacy.Results: Data from sentinel site ophthalmology centers and laboratories revealed that the yearly number of cases gradually increased from 22 in 1999 to 43 in 2003, with a marked increase beginning in 2004 (93 cases) that continued through 2007 (170 cases; p < 0.0001). The outbreak identified from these sentinel sites resulted in the recall of a contact lens disinfecting solution. There was a statistically significant (p ≤ 0.0001) decrease in monthly cases reported from 28 cases in June 2007 (following the recall) to seven cases in June 2008, followed by an increase (p = 0.0004) in reported cases thereafter; cases have remained higher than pre-outbreak levels. A similar trend was seen in prescriptions for Acanthamoeba keratitis chemotherapy. Cases were significantly more likely to be reported during summer than during other seasons.Conclusion: The persistently elevated number of reported cases supports the need to understand the risk factors and environmental exposures associated with Acanthamoeba keratitis. Further prevention efforts are needed to reduce the number of cases occurring among contact lens wearers.

Pan-Antimicrobial Failure of Alexidine as a Contact Lens Disinfectant When Heated in Bausch &amp; Lomb Plastic Containers

ReNu with MoistureLoc (ReNuML), containing the antimicrobial agent alexidine 0.00045%, was associated with the Fusarium keratitis epidemic of 2004 to 2006. Although a single-point source contamination was ruled out, only Fusarium organisms were reported during the outbreak. This study investigated whether the reported loss of antimicrobial effectiveness toward Fusarium of ReNuML after exposure to heat in high-density polyethylene (HDPE) plastic containers could also be demonstrated with other common fungal and bacterial agents of keratitis. A buffered solution of alexidine 0.00045% was incubated in glass and ReNu HDPE plastic containers at room temperature (RT) and 56°C for 4 weeks, serially diluted, and tested for its ability to inhibit the growth of 20 bacterial isolates, 12 non-Fusarium fungal isolates, and 7 Fusarium isolates originally involved in the keratitis epidemic. A statistically significant loss of antimicrobial capability was seen with all fungi, all gram-positive bacteria, and all isolates of Klebsiella when alexidine 0.00045% was incubated at 56°C in ReNu HDPE containers compared with RT or glass incubation (P≤0.0001). Heating of an alexidine solution in ReNu HDPE plastic (but not glass) containers results in the same loss of anti-Fusarium activity as reported when testing the original ReNuML solution. This loss of inhibitory activity is not specific to Fusarium and occurs with other fungi and bacteria that cause keratitis. The reasons for the lack of reports of bacterial and/or non-Fusarium fungal keratitis during the original Fusarium keratitis epidemic remain unclear at this time.

Antifungal efficacy of soft contact lens disinfecting solutions against Fusarium solani and Candida albicans

Purpose: The aim was to evaluate the disinfection properties of six multi‐purpose contact lens disinfection solutions (MPDS) available in Iran against Fusarium solani and Candida albicans, based on the International Organization for Standardization (ISO) 14729 guidelines.Methods: Three lots each of six multi‐purpose solutions, namely, Renu MultiPlus, Solo Care Aqua, All‐Clean soft, Contact All In One Advanced, Hippia, Ginza Multi‐Purpose Solution and 0.9% normal saline solution were inoculated with standard strains of Fusarium solani (ATCC 36031) and Candida albicans (ATCC 10231). Surviving fungi were determined by counting colony‐forming units on recovery plates at specified times. The mean log reduction in fungal numbers at the manufacturer's minimum recommended disinfection time was determined and compared with the criteria for stand‐alone disinfection products for each MPDS against each fungal strain.Results: Renu MultiPlus, Contact All In One Advanced and All‐Clean Soft were effective in achieving the mean 1.0 log reduction in fungal numbers, based on ISO 14729 stand‐alone primary acceptance criteria. Solo Care Aqua failed to achieve the ISO 14729 stand‐alone primary acceptance criteria for Candida albicans. The other solutions were not effective against test microorganisms after the specified times.Conclusions: There were differences in the rates of disinfection efficacy. Generally, Renu MultiPlus, Contact All In One Advanced and All‐Clean Soft exceeded the primary acceptance criteria of the ISO 14729 guidelines for stand‐alone contact lens solutions.

Real-time In-situ Detection of Microbes

Currently, no methods exist for the real-time detection and quantification of microbes in the environment or for the detection and identification of pathogenic organisms in clinical specimens. We have developed technologies which overcome these limitations and provide detection limits as low as a ten microbial cells per cm2 on abiotic surfaces, and per mL in fluids. The detection and quantification of microbes [total microbial load] is based on the intrinsic fluorescence of microbial metabolites and protein cofactors, and provides an estimate of the total microbial load as well as the relative distribution of live cells, dead cells, and endospores. Unlike existing methods, no additional reagents or sample contact is needed. This technology has been applied to the in-situ measurements of two sub-glacial microbial communities at sites in the Svalbard Archipelago, Norway, and to the efficacy of disinfection of contact lenses. In the rapid spread of a life-threatening infection, early diagnosis is of great importance. In such situations, pathogen counts will be very low, which also presents a significant challenge to diagnostic methods. We have developed a point of care disposable diagnostic based on the en masse capture of blood-borne microbes from 1 mL of fresh whole blood with surface-tethered, small molecule ligands. Quantification is based on the intrinsic fluorescence of captured cells.

A New Method for Evaluation of Compatibility of Contact Lenses and Lens Cases With Contact Lens Disinfecting Solutions

The purpose of this article is to describe new methodology, antimicrobial efficacy endpoint methodology to determine compatibility of contact lens solutions, lens cases and hydrogel lenses for disinfection (AEEMC), to evaluate the effect of a contact lens and a lens case on disinfection efficacy, and to present the ring test used to justify the use of the method in multiple laboratories. A prototype solution containing chlorhexidine as the disinfecting agent and four representative lens types (group I and IV hydrogels and two silicone hydrogels) were used in these ring tests. Five laboratories participated in the chemical and microbiologic analyses. The residual chlorhexidine in lens cases containing the contact lenses was determined using high-performance liquid chromatography; uptake by the lenses was then determined by extrapolation. For the microbiologic part of the study, a contact lens was placed in the well of the lens case, inoculated at 10 to 10 cfu (colony forming units) per lens with microorganisms in 10% organic soil. The microorganisms, Pseudomonas aeruginosa, Serratia marcescens, Staphylococcus aureus, Candida albicans, and Fusarium solani, were prepared as in International Organization for Standardization (ISO) 14729. After a 3- to 10-min exposure time, the prototype solution was dispensed into each well. Aliquots of the inoculated solutions were removed at 4 and 24 hrs and 7 and 30 days and cultured in neutralizing media for determination of survivors; lenses were also cultured for survivors. Chemical uptake data confirmed the differences observed in kill of the challenge organisms according to lens type. It was observed that the culturing of the solution provided adequate data to show the effect of a lens on disinfection efficacy of a lens care product. The findings of the ring test indicated that the separate culturing of the contact lenses is not necessary for routine assessment. The methodology in the November 12, 2008, draft standard (AEEMC), meets the stated objective of demonstrating the effect of a contact lens on the disinfection efficacy of a simulated lens care product. This method, used in combination with the methodology in ISO 14729, should provide for a more robust evaluation of applicable contact lens care disinfecting products.

Amoebicidal Effects of Contact Lens Disinfecting Solutions

To compare the traditional manual hemacytometer method and an automated counter (Vi-cell) to enumerate and distinguish between viable and non-viable amoeba, and to determine the efficacies of contact lens (CL) disinfecting solutions against three species of Acanthamoeba. The efficacies in the presence of a bacterial food source and bovine serum albumin (BSA) were investigated. Four brands of multipurpose solutions and a hydrogen peroxide disinfecting system (Oxysept) for soft CLs, and four disinfecting solutions for Rigid Gas Permeable (RGP) lenses were tested against three species of Acanthamoeba. Page's amoebic saline was included as a negative control and standard solutions of disinfecting agents, 6% hydrogen peroxide and 0.5% chlorhexidine, as positive controls. The effects of the presence of Pseudomonas aeruginosa and BSA on effectiveness were assessed. None of the CL solutions tested achieved a 1-log reduction in viability of all three Acanthamoeba species within the manufacturer's recommended disinfection times. The presence of P. aeruginosa did not significantly affect disinfecting capacity of multipurpose solution solutions but reduced activity of RGP solutions and the hydrogen peroxide system. BSA reduced trophozoicidal activity of all solutions. Bland and Altman analysis showed good agreement between Vi-cell and hemacytometer. The Vi-Cell analyzer offers a simple and effective method of determining amoebicidal activity. Our results show that the CL solutions tested could not satisfactorily kill Acanthamoeba.

56 Efficacy of contact lens care solutions against clinical microorganisms

Purpose: To evaluate the efficacy of a new contact lens disinfecting solution. Method: The efficacy of a new contact lens disinfecting solution with a dual disinfection system was assessed against standard challenge microorganisms and clinical isolates of Acanthamoeba castellanii, Acanthamoeba polyphaga, Staphylococcus aureus, Pseudomonas aeruginosa, Serratia marcescens, Candida albicans, and Fusarium solani using stand-alone microbiological test methodology. Additionally, the efficacy of recently marketed contact lens care solutions, including Revitalens and Biotrue, was tested against standard challenge microorganisms. The stand-alone test is a time kill study designed to qualify individual solutions with a suitable level of antimicrobial activity as contact lens disinfection products. Results: After six hours of disinfection time, the OPTI-FREE EverMoist showed ∼2 logs kill against cysts of A. castellanii ATCC30234 and A. polyphaga ATCC 30871. OPTI-Free EverMoist met the primary Stand-alone criteria with efficacies of more than 4 log reductions for each of the three standard bacteria and each standard yeast and mold. All tested marketed contact lens care solutions showed efficacy against standard challenge microorganisms. Clinical isolates of Staphylococcus aureus, Pseudomonas aeruginosa, Serratia marcescens, and Candida albicans were reduced by approximately 4 logs or greater after six hours of exposure to OPTI-FREE EverMoist. Conclusions: OPTI-FREE EverMoist MPDS provides broad spectrum antimicrobial activity against a variety of challenge ATCC and clinical microorganisms. OPTI-FREE EverMoist leverages the proven PolyQuad® and Aldox® dual disinfection system to provide excellent antimicrobial efficacy.

55 Antimicrobial properties of a novel contactions disinfecting solution, OPTI-FREE EverMoist

Purpose: To evaluate the efficacy of a new contact lens disinfecting solution. Method: The efficacy of a new contact lens disinfecting solution with a dual disinfection system was assessed against standard challenge microorganisms and clinical isolates of Acanthamoeba castellanii, Acanthamoeba polyphaga, Staphylococcus aureus, Pseudomonas aeruginosa, Serratia marcescens, Candida albicans, and Fusarium solani using stand-alone microbiological test methodology. Additionally, the efficacy of recently marketed contact lens care solutions, including Revitalens and Biotrue, was tested against standard challenge microorganisms. The stand-alone test is a time kill study designed to qualify individual solutions with a suitable level of antimicrobial activity as contact lens disinfection products. Results: After six hours of disinfection time, the OPTI-FREE EverMoist showed ∼2 logs kill against cysts of A. castellanii ATCC30234 and A. polyphaga ATCC 30871. OPTI-Free EverMoist met the primary Stand-alone criteria with efficacies of more than 4 log reductions for each of the three standard bacteria and each standard yeast and mold. All tested marketed contact lens care solutions showed efficacy against standard challenge microorganisms. Clinical isolates of Staphylococcus aureus, Pseudomonas aeruginosa, Serratia marcescens, and Candida albicans were reduced by approximately 4 logs or greater after six hours of exposure to OPTI-FREE EverMoist. Conclusions: OPTI-FREE EverMoist MPDS provides broad spectrum antimicrobial activity against a variety of challenge ATCC and clinical microorganisms. OPTI-FREE EverMoist leverages the proven PolyQuad® and Aldox® dual disinfection system to provide excellent antimicrobial efficacy.

57 Relationship between disinfecting efficacy of multi-purpose contact lens care solutions and encystment rate of Acanthamoeba

Purpose: To evaluate the efficacy of a new contact lens disinfecting solution. Method: The efficacy of a new contact lens disinfecting solution with a dual disinfection system was assessed against standard challenge microorganisms and clinical isolates of Acanthamoeba castellanii, Acanthamoeba polyphaga, Staphylococcus aureus, Pseudomonas aeruginosa, Serratia marcescens, Candida albicans, and Fusarium solani using stand-alone microbiological test methodology. Additionally, the efficacy of recently marketed contact lens care solutions, including Revitalens and Biotrue, was tested against standard challenge microorganisms. The stand-alone test is a time kill study designed to qualify individual solutions with a suitable level of antimicrobial activity as contact lens disinfection products. Results: After six hours of disinfection time, the OPTI-FREE EverMoist showed ∼2 logs kill against cysts of A. castellanii ATCC30234 and A. polyphaga ATCC 30871. OPTI-Free EverMoist met the primary Stand-alone criteria with efficacies of more than 4 log reductions for each of the three standard bacteria and each standard yeast and mold. All tested marketed contact lens care solutions showed efficacy against standard challenge microorganisms. Clinical isolates of Staphylococcus aureus, Pseudomonas aeruginosa, Serratia marcescens, and Candida albicans were reduced by approximately 4 logs or greater after six hours of exposure to OPTI-FREE EverMoist. Conclusions: OPTI-FREE EverMoist MPDS provides broad spectrum antimicrobial activity against a variety of challenge ATCC and clinical microorganisms. OPTI-FREE EverMoist leverages the proven PolyQuad® and Aldox® dual disinfection system to provide excellent antimicrobial efficacy.

58 Biocidal efficacy of multipurpose contact lens disinfectant solutions against Acanthamoeba species

Purpose: To evaluate the efficacy of a new contact lens disinfecting solution. Method: The efficacy of a new contact lens disinfecting solution with a dual disinfection system was assessed against standard challenge microorganisms and clinical isolates of Acanthamoeba castellanii, Acanthamoeba polyphaga, Staphylococcus aureus, Pseudomonas aeruginosa, Serratia marcescens, Candida albicans, and Fusarium solani using stand-alone microbiological test methodology. Additionally, the efficacy of recently marketed contact lens care solutions, including Revitalens and Biotrue, was tested against standard challenge microorganisms. The stand-alone test is a time kill study designed to qualify individual solutions with a suitable level of antimicrobial activity as contact lens disinfection products. Results: After six hours of disinfection time, the OPTI-FREE EverMoist showed ∼2 logs kill against cysts of A. castellanii ATCC30234 and A. polyphaga ATCC 30871. OPTI-Free EverMoist met the primary Stand-alone criteria with efficacies of more than 4 log reductions for each of the three standard bacteria and each standard yeast and mold. All tested marketed contact lens care solutions showed efficacy against standard challenge microorganisms. Clinical isolates of Staphylococcus aureus, Pseudomonas aeruginosa, Serratia marcescens, and Candida albicans were reduced by approximately 4 logs or greater after six hours of exposure to OPTI-FREE EverMoist. Conclusions: OPTI-FREE EverMoist MPDS provides broad spectrum antimicrobial activity against a variety of challenge ATCC and clinical microorganisms. OPTI-FREE EverMoist leverages the proven PolyQuad® and Aldox® dual disinfection system to provide excellent antimicrobial efficacy.

60 Biocidal efficacy of multipurpose contact lens disinfectant solutions and antimicrobial storage cases against Stenotrophomonas and Delftia: resistance and re-growth

60 Biocidal efficacy of multipurpose contact lens disinfectant solutions and antimicrobial storage cases against Stenotrophomonas and Delftia: resistance and re-growth

Effects of Peroxide-Based Contact Lens–Disinfecting Systems on Human Corneal Epithelial Cells In Vitro

To evaluate the effects of residual hydrogen peroxide (H2O2) in neutralized H2O2-based contact lens-disinfecting solutions on morphology, viability, and barrier function of monolayer and stratified human corneal-limbal epithelial (HCLE) cells. Cells were exposed to contact lens formulations containing 0.01% H2O2 for 10, 20, or 60 minutes. The morphology of monolayer or stratified cells was observed by microscopy. Monolayer or stratified cell viability was determined using a live/dead assay, and monolayer cell viability was quantified using flow cytometry. Effects of formulations on barrier function of stratified HCLE cells were evaluated by measuring fluorescein permeability and transepithelial resistance of cultures grown on membrane inserts. To determine the sensitivity of the tests to peroxide damage, stratified cells were also exposed to 0.01% to 0.3% H2O2 in culture medium. All formulations caused swelling of monolayer cells. Formulations with or without H2O2 at pH 7.9 caused mild decreases in monolayer cell viability but did not affect viability or barrier function of stratified HCLE cells. H2O2 (≥0.1%) in culture medium caused damage without recovery to stratified HCLE cells. Although tests on stratified cells are capable of detecting damage caused by H2O2 in culture medium, residual H2O2 in neutralized ophthalmic formulations had no effect on stratified cells in vitro. These data suggest that H2O2, used appropriately, is a safe disinfectant. Data comparing monolayer and stratified cultures suggest that monolayers are more sensitive to peroxide damage and that the effects of neutralized formulations on stratified cells may better predict the intact corneal epithelial response.

Efficacy of commercial soft contact lens disinfectant solutions against Acanthamoeba

To investigate the relative efficacy of Japanese commercial soft contact lens disinfectant solutions against Acanthamoeba trophozoites and cysts. Eight types of multipurpose solution (MPS), two types of hydrogen peroxide solution, and one povidone-iodine solution were evaluated to determine their effect against Acanthamoeba trophozoites and cysts (ATCC 50514). Acanthamoeba cysts were cultured in encystment medium for either 1 or 2weeks (1 and 2-week-old cysts). The trophozoites and cysts were treated with each disinfectant solution for 0, 2, 4, 8, or 24h. After performing four tenfold serial dilutions of each test solution, dilutions were cultured for 10days. The number of surviving organisms was calculated using the trimmed Spearman-Karber method. Among the MPS tested, only four were effective against trophozoites after treatment for 4h, and none was effective against 2-week-old cysts. Hydrogen peroxide had a significant effect on trophozoites and 1-week-old cysts, but not on 2-week-old cysts. In contrast, povidone-iodine caused a 2.6 log reduction in 2-week-old cysts. MPS were found to have limited efficacy against trophozoites and no efficacy against 2-week-old cysts. Only povidone-iodine had any efficacy against 2-week-old cysts.

Comparative efficacies of contact lens disinfecting solutions against Pseudomonas aeruginosa

Purpose: The aim of the present study was to evaluate the disinfection properties of multipurpose contact lens disinfection solutions, based on the International Organization for Standardization (ISO) 14729 guidelines.Methods: Three lots of each of six multi‐purpose solutions were tested as follows: Renu MultiPlus, Solo Care Aqua, All‐Clean Soft, Contact All‐in one Advanced, Hippia, Ginza multi‐purpose solution and 0.9% normal saline solution were inoculated with the standard strain of Pseudomonas aeruginosa (ATCC 9027). The surviving bacteria were quantified at specified times. An average logarithm reduction in bacterial numbers at the manufacturer's minimum recommended disinfection time was determined and compared with the criteria for stand‐alone disinfection products for each multi‐purpose disinfection solution against each bacterial strain.Results: Renu MultiPlus, Solo Care, All‐Clean Soft and Contact All‐in one Advanced were effective in achieving a four logarithmic units reduction in the bacterial count; however, Renu MultiPlus and Solo Care Aqua resulted in the greatest reduction in bacterial numbers. The other solutions were not effective against Pseudomonas aeruginosa after specified times.Conclusions: Generally, Renu MultiPlus, Solo Care Aqua, All‐Clean Soft and Contact All‐in one Advanced meet the ISO 14729 guidelines for stand‐alone contact lens solutions.

In Vitro Interactions ofFusariumandAcanthamoebawith Drying Residues of Multipurpose Contact Lens Solutions

To examine in vitro effects of evaporation and drying of multipurpose contact lens solutions on survival of Fusarium and Acanthamoeba. Conidia of representative Fusarium from the 2004-2006 keratitis outbreak and trophozoites of Acanthamoeba castellanii were inoculated into commercially available multipurpose contact lens care solutions. These solutions were inoculated with 10(2)-10(6) microbial propagules/mL and were evaporated for at least 24 hours. After drying, nutrient media for recovery of surviving organisms were added to the residues formed in the lids of 38 mm polystyrene Petri dishes. General morphologic patterns of the solution residuals and the distribution and morphologies of the microorganisms were recorded with microscopic imaging. Various multipurpose contact lens disinfection solutions formed distinctive dried residual patterns. Both Fusarium and Acanthamoeba at concentrations tested above 10(3) per mL of disinfection solution were recovered from dried films with replicate testing. Mature cysts of Acanthamoeba not evident in the inocula were observed in sparse numbers in all dried solutions except one (Complete Moisture Plus; Advanced Medical Optics) and control salines where precysts and mature cysts were common. Both fusaria and amoeba tended to be observed in discrete regions of the dried residues. Regions of drying films of multipurpose contact lens disinfection solutions on contact lens cases may induce and harbor dormant-resistant stages of Fusarium and Acanthamoeba. It is hypothesized that the evaporation and drying of multipurpose contact lens disinfection solutions may have been an added risk factor for case contamination among Fusarium and Acanthamoeba keratitis patients. The need for frequent replacement of contact lens cases is enforced.

Antimicrobial efficacy of multi-purpose contact lens disinfectant solutions following evaporation

Non-compliance is a significant factor in contact lens related microbial keratitis and includes solution reuse and failure to recap the lens storage case resulting in evaporation effects. To address this, impact of partial evaporation on the antimicrobial efficacy of multipurpose contact lens care solutions was investigated. Solutions were evaporated under a stream of air to 2× and 4× concentration and challenged with Fusarium solani (ATCC 36031), Candida albicans (ATCC 10231) and Acanthamoeba castellanii (ATCC 50370). The level of organism kill at 6h was compared to the non-evaporated product. ReNu with MoistureLoc(®) (RML) lost 90-100% of biocidal activity against C. albicans on evaporation, 75-99% for F. solani and 29-33% with A. castellanii at 2× or 4× concentration, respectively. OPTI-FREE(®) RepleniSH(®) lost 72-90% efficacy against C. albicans and F. solani, and 61% at 2× and 10% at 4× concentration with A. castellanii. ReNu(®) MultiPlus, AQuify(®) Multi-Purpose and Biotrue™ showed only loss in efficacy with C. albicans at 4× concentration giving 79%, 34.5% and 48% reduction, respectively. No loss in biocidal activity on evaporation was obtained with Complete(®) Revitalens for all organisms. Partial evaporation can affect biocidal efficacy of multi-purpose solutions and may have been a significant factor in an outbreak of Fusarium keratitis cases associated with RML. Evaporation results in increased binding of cationic disinfectants to counter-ions in the formulation, reducing ability to attach and rupture anionic microbial cell walls. Interaction may also occur between the biocidal ingredient and other components, such as surfactants, resulting in sequestration of activity through micelle formation.