Multipurpose Disinfecting Solution Research Articles

BT100, a three-in-one, multipurpose disinfecting, deodorizing, and air-cleaning solution with an effective, gradual, and continuous gaseous chlorine dioxide-releasing substance

Aerosols carrying viruses that are released from the oral cavity of infected individuals are the primary, if not the only, means of transmission during viral respiratory disease epidemics. This makes crowded rooms and tiny, enclosed public areas like bathrooms prime environments for the transmission of diseases. Volatile organic compounds (VOCs) and formaldehyde are two contaminants that pose serious threats to human health and well-being in indoor environments. The varied disinfectant properties of chlorine dioxide (ClO2) make it a key player in treating a range of air quality issues. To balance effectiveness and safety, however, the careful application of chlorine dioxide is essential to achieving the best results in air quality while preserving human health and well-being. This study explores the many functions of chlorine dioxide, including the prevention of the spread of viruses, the elimination of harmful gases like ammonia and hydrogen sulfide, and its effects on formaldehyde and total volatile organic compounds (TVOCs) in indoor environments using BT100. The results indicate a reduction of 98.5%, 81.01%, 62.22%, 46.5%, and 63.84% in minimizing aerosolized viruses, ammonia, and hydrogen sulfide gas in addition to formaldehyde and total volatile organic compounds.

Polyhexamethylene Biguanide Multipurpose Solutions on Bacterial Disinfection: A Comparison Study of Effectiveness in a Developing Country.

The aim of this study was to compare the antimicrobial action of commercially available multipurpose disinfection solutions (MPDS) with and without hydrogel contact lens for disinfection of isolated corneal bacteria. Five commercially available MPDS in Brazil (BioSoak, Clear Lens, OPTI-FREE, Renu, and UltraSept) were tested against Pseudomonas aeruginosa , Staphylococcus aureus , and Staphylococcus epidermidis . All five MPDS were also tested on P. aeruginosa and S. aureus biofilm in a Hioxifilcon A lens. OPTI-FREE and Renu were effective against all bacterial isolates without contact lenses. BioSoak was effective in inhibiting P. aeruginosa and S. epidermidis but not against S. aureus . UltraSept was effective for inhibiting S. epidermidis and S. aureus but not against P. aeruginosa . Clear Lens was effective in inhibiting only S. epidermidis but not P. aeruginosa and S. aureus . In contact lens bacterial biofilms, OPTI-FREE was the only MPDS to demonstrate significantly higher disinfection. MPDS containing dual biocides polyquaternium-1 and myristamidopropyl dimethylamine possess the highest disinfection action against multiple ocular pathogens with and without contact lenses when compared with other MPDS. Current single-action polyhexamethylene biguanide solutions are not entirely effective and should not be recommended.

Susceptibility of Ocular Staphylococcus aureus to Antibiotics and Multipurpose Disinfecting Solutions.

Staphylococcus aureus is a frequent cause of ocular surface infections worldwide. Of these surface infections, those involving the cornea (microbial keratitis) are most sight-threatening. S. aureus can also cause conjunctivitis and contact lens-related non-infectious corneal infiltrative events (niCIE). The aim of this study was to determine the rates of resistance of S. aureus isolates to antibiotics and disinfecting solutions from these different ocular surface conditions. In total, 63 S. aureus strains from the USA and Australia were evaluated; 14 were from niCIE, 26 from conjunctivitis, and 23 from microbial keratitis (MK). The minimum inhibitory (MIC) and minimum bactericidal concentrations (MBC) of all the strains to ciprofloxacin, ceftazidime, oxacillin, gentamicin, vancomycin, chloramphenicol, azithromycin, and polymyxin B were determined. The MIC and MBC of the niCIE strains to contact lens multipurpose disinfectant solutions (MPDSs) was determined. All isolates were susceptible to vancomycin (100%). The susceptibility to other antibiotics decreased in the following order: gentamicin (98%), chloramphenicol (76%), oxacillin (74%), ciprofloxacin (46%), ceftazidime (11%), azithromycin (8%), and polymyxin B (8%). In total, 87% of all the isolates were multidrug resistant and 17% of the isolates from microbial keratitis were extensively drug resistant. The microbial keratitis strains from Australia were usually susceptible to ciprofloxacin (57% vs. 11%; p = 0.04) and oxacillin (93% vs. 11%; p = 0.02) compared to microbial keratitis isolates from the USA. Microbial keratitis isolates from the USA were less susceptible (55%) to chloramphenicol compared to conjunctivitis strains (95%; p = 0.01). Similarly, 75% of conjunctivitis strains from Australia were susceptible to chloramphenicol compared to 14% of microbial keratitis strains (p = 0.04). Most (93%) strains isolated from contact lens wearers were killed in 100% MPDS, except S. aureus 27. OPTI-FREE PureMoist was the most active MPDS against all strains with 35% of strains having an MIC ≤ 11.36%. There was a significant difference in susceptibility between OPTI-FREE PureMoist and Biotrue (p = 0.02). S. aureus non-infectious CIE strains were more susceptible to antibiotics than conjunctivitis strains and conjunctivitis strains were more susceptible than microbial keratitis strains. Microbial keratitis strains from Australia (isolated between 2006 and 2018) were more susceptible to antibiotics in comparison with microbial keratitis strains from the USA (isolated in 2004). Most of the strains were multidrug-resistant. There was variability in the susceptibility of contact lens isolates to MPDSs with one S. aureus strain, S. aureus 27, isolated from niCIE, in Australia in 1997 being highly resistant to all four MPDSs and three different types of antibiotics. Knowledge of the rates of resistance to antibiotics in different conditions and regions could help guide treatment of these diseases.

Influence of Contact Lens Materials and Cleaning Procedures on Bacterial Adhesion and Biofilm Formation.

PurposeThe present study aimed to compare the existing soft contact lens (CL) materials regarding their influence on bacterial biofilm formation and adhesion susceptibility. Then, the study was designed to investigate the effectiveness of various disinfecting solutions and evaluate the ability of cleaning regimens in terms of anti-bacterial adhesion and biofilm removal on different soft CL materials.MethodsBacterial biofilm formation on CLs was evaluated by biomass assay. Adhesion assay and standard plate count were carried out at time-interval periods within 24 h. Various CL disinfecting procedures were assessed for their efficacy to remove biofilm and reduce bacterial adhesion. Scanning electron microscopy (SEM) was performed for the morphological assessment of bacterial biofilm.ResultsPrinted hydroxyethyl methacrylate (HEMA) CLs significantly demonstrated more biofilm staining and bacterial attachment when compared with non-printed HEMA CLs, while the Filcon II 3 and Nesofilcon A CLs possessed less biofilm biomass and adherent cells. Staphylococcus aureus and Pseudomonas aeruginosa represented the highest biofilm producing bacteria on HEMA-based materials in this study. The disinfecting regimen with the highest efficacy was the two-step system, first using multipurpose disinfecting solution containing edetate disodium and sorbic acid (MPDS+EDSA), followed by soaking in multipurpose solution (MPS). The regimen demonstrated the greatest effect against the pre-formed biofilm and the adhesion activity of S. aureus and P. aeruginosa on the soft CLs. The SEM micrographs confirmed the morphological changes of bacterial biofilm after disinfecting and revealed that the two-step system treated CLs displayed less adherent bacteria.ConclusionHEMA-based soft CLs may facilitate bacterial biofilm formation and adhesion capability. The two-step system was the most effective regimen for biofilm removal, where the soaking period in the disinfecting solution of the no-rub regimen should last more than 6 h to remove pre-formed biofilm.

Effect of Hygiene Procedures on Lens Case Contamination with Povidone-Iodine or Multipurpose Disinfecting Solutions.

A multipurpose disinfecting solution (MPDS), which contains povidone-iodine (PI) as a disinfectant, has high disinfecting efficacy not only on planktonic bacterium but also on the case biofilms. The addition of case hygiene practice removed more bacteria from cases than MPDS alone. This study compared the ability of two MPDSs, one containing PI and another containing polyaminopropyl biguanide and polyquaternium, to reduce bacterial numbers in solution or adhered to the cases following case hygiene procedures. Bacterial strains (Delftia acidovorans, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Serratia marcescens, Staphylococcus aureus, and Staphylococcus epidermidis) were exposed to the MPDSs for the recommended disinfection times, and the viable number evaluated according to ISO 14729. Cases were inoculated with bacterial strains and incubated for 24 hours to allow for biofilm formation. Cases were disinfected with both disinfecting solutions for 4 hours and rinsed, followed by recapping or air-drying, or tissue-wiping and air-drying for 18 hours. The number of survivors was counted using standard culture techniques. Both products exceeded the recommended 3-log reduction against planktonic bacteria. Regarding biofilm, after rinsing and recapping wet, the numbers of D. acidovorans (mean difference [95% confidence interval] log10 colony-forming units per case, -2.9 [0.8 to -4.6], P < .01), P. aeruginosa (-2.0 [0.5 to -3.1], P < .01), S. marcescens (-1.7 [0.8 to -3.5], P < .05), and S. epidermidis (-2.1 [0.6 to -3.5], P < .05) in PI cases were significantly lower than in the dual-disinfectant MPDS storage cases. After air-drying, the PI storage cases had significantly lower numbers of S. maltophilia (-2.6 [0.6 to -4.0], P < .01), D. acidovorans (-1.6 [0.7 to -3.3], P < .05), and S. aureus (-1.6 [0.7 to -3.1], P < .05). The addition of tissue-wiping reduced the bacterial numbers in the MPDS storage cases to levels in the PI storage cases. Contact lens users should be recommended to tissue-wipe and air-dry their lens storage cases after disinfection with regular MPDS.

In vitro effects of multi-purpose contact lens disinfecting solutions towards survivability of Acanthamoeba genotype T4 in Malaysia.

The incidence of Acanthamoeba keratitis has been increasing since the previous decades, especially among contact lens users. This infection is majorly caused by the use of ineffective contact lens disinfecting solution. Thus, this study was conducted to evaluate the in vitro effects of multi-purpose disinfecting solutions (MPDS) against Acanthamoeba trophozoites and cysts. Acanthamoeba genotype T4 isolated from contact lens paraphernalia and an environmental strains were propagated for trophozoite or cyst-containing culture and adjusted in final concentration of 1 × 105 cells/ml. Amoebicidal and cysticidal assays were conducted by incubating trophozoites and cysts with OPTI-FREE® Express®, ReNu® Fresh™, Complete® Multi-Purpose Solution and AVIZOR Unica® Sensitive according to the manufacturer’s minimum recommended disinfectant time (MMRDT) for up to 12 h at 30 ⁰C. Trypan blue hemocytometer-based microscopic counts determined amoebicidal and cysticidal effects. The viability of Acanthamoeba trophozoites and cysts was confirmed by re-inoculated them in the 1.5% non-nutrient agar plates. It was found that none of the MPDS showed amoebicidal and cysticidal effects during the MMRDT. However, OPTI-FREE® Express® demonstrated a significant differences in average cell reduction for both stages within MMRDT. When subjected to 12 h exposure, both OPTI-FREE® Express® and ReNu® Fresh™ led to significant reduction in the number of trophozoite and cyst cells. Notably, Complete® Multi-Purpose Solution and AVIZOR Unica® Sensitive did appreciably improve the solution effectiveness towards trophozoite cells when incubated for 12 h. All MPDS were largely ineffective, with 100% survival of all isolates at MMRDT, while OPTI-FREE® Express® showed limited amoebicidal activity against the contact lens paraphernalia isolate, however, it was more against the environmental strains after 12 h incubation time. The commercially available MPDS employed in this research offered minimal effectiveness against the protozoa despite the contact time. Improvement or development of new solution should consider the adjustment of the appropriate disinfectant concentration, adequate exposure time or the incorporation of novel chemical elements, which are effective against Acanthamoeba for accelerated disinfecting and more reduction of potential exposure of contact lens users to Acanthamoeba keratitis.

Multi-purpose Disinfecting Solutions only Partially Inhibit the Development of Ocular Microbes Biofilms in Contact Lens Storage Cases.

PURPOSE:Certain ocular resident or pathogenic microbes may remain viable in the presence of multi-purpose disinfectant solutions (MPDSs), subsequently developing biofilms inside contact lens storage cases (CLSCs) which pose a risk of infection to wearers. This study evaluated the formation of ocular microbiota biofilms exposed to three top selling MPDS.METHODS:Crystal violet assay was carried out for the verification of biofilm formation. The in vitro assays evaluated Pseudomonas aeruginosa UFPEDA 416 and Staphylococcus aureus UFPEDA 02 exposure of 48 h to MPDS, as well as the use of 40 KHz ultrasound at the beginning and with 24 h immersion in the MPDS. Subsequently, in vivo assays evaluated the formation of microbial biofilms on the CLSC walls containing silicone-hydrogel contact lenses immersed in MPDS from 15 healthy volunteer patients, who had been wearing the lenses for 7 days.RESULTS:Biofilms were inhibited by 26%–98% in the in vitro assays, with a statistically significant difference only for P. aeruginosa UFPEDA 416 exposed to diluted MPDS. Most inhibitions occurred moderately and weakly. In addition, adherent cells were detected in more than 90% of the tests. Biofilm was not inhibited in more than one third of the results, nor was it disturbed, especially with the ultrasound treatments. The average of obtained optical densities at 590 nm was between 0.6 and 0.8 in the in vivo assays. The results were similar between the CLSC right and left wells. There was a correlation between microbial biofilm formation and the type of MPDS tested, with statistical difference between the three treatments.CONCLUSION:MPDS promoted a partial inhibition of microbial biofilm formation but only one MPDS proved to be more effective in vitro and in vivo. This study, however, could not distinguish the effect of possible errors in the good hygiene practices of the users.

The Antimicrobial Activity of Multipurpose Disinfecting Solutions in the Presence of Different Organic Soils

During use, contact lens disinfecting solutions are exposed to tears and clinical microbial isolates. The current study was designed to test the performance of several disinfecting solution in the presence of organic soils or clinical isolates. Standard and clinical isolates were exposed to the disinfecting solutions in the presence or absence of different organic soils. The number of microbial cells killed during disinfection was established by growing cells after disinfection on agar plates. The disinfecting activity of the povidone-iodine or hydrogen peroxide solutions was not affected by the organic soils or clinical isolates. The presence of yeast organic soil did not affect the performance of the disinfecting solutions when tested with standard microbial strains, but the addition of a model tear organic soil significantly reduced the disinfecting activity of the solutions containing various combinations of polyhexamethylene biguanide, polyquaternium-1, alexidine, and myristamindopropyl dimethylamine especially when tested against the standard fungal strains (reducing the effectiveness by between 0.5-4 log10) or the clinical bacterial isolates (reducing the effectiveness by between 0.5-3.5 log10). One disinfecting solution that contained polyquaternium-1 and myristamindopropyl dimethylamine had very poor activity against the clinical bacterial isolates in the absence or presence of either organic soil. Povidone-iodine or hydrogen peroxide disinfecting solutions are not affected by organic soils and are very active against clinical bacterial isolates. Disinfecting solutions containing combinations of polyhexamethylene biguanide, polyquaternium-1, alexidine, and myristamindopropyl dimethylamine are affected by model tear organic soil and may have poor activity against clinical isolates.

In Vitro Antimicrobial Efficacy of Silver Lens Cases Used With a Multipurpose Disinfecting Solution.

PurposeWe evaluate the in vitro antibacterial activity of silver-copolymerized barrel cases compared to nonsilver barrel cases in combination with a multipurpose disinfecting solution (MPDS).MethodsThe ability of silver and nonsilver cases to reduce the number of adherent Gram-positive and Gram-negative bacteria was assessed. Additionally, the efficacy of silver cases along with MPDS was investigated in the presence of organic soil and contact lenses. Contact lens cases were challenged with 106 colony-forming units (CFU)/mL of five bacterial species. Adherent bacteria were dislodged from lens cases and surviving organisms enumerated.ResultsSignificantly lower numbers of microbes were recovered from silver cases compared to controls, for all bacterial strains (P < 0.005). The combination of silver case along with MPDS showed added efficacy against Gram-positive and -negative bacteria with a maximum reduction of 3.00 ± 0.5 Log10 CFU/mL, compared to the efficacy of silver cases alone (1.97 ± 0.4 Log10 CFU/mL). The addition of organic soil and a contact lens resulted in a significant (P < 0.005) decrease (a maximum of 1.68 ± 0.2 log10 CFU/mL) in disinfection efficacy when MPDS and either silver or control cases were used.ConclusionsSilver-copolymerized barrel cases work on conjunction with a hypochlorite producing MPDS in the presence of contact lenses and organic soil to reduce microbial contamination of lens cases.Transitional RelevanceSilver-copolymerized barrel contact lens cases show promising in vitro antibacterial activity against bacterial types commonly implicated in contact lens-related corneal infections. This intervention may limit storage case contamination during use and reduce the frequency of contact lens-related microbial disease.

Study of Disinfectant Resistance Genes in Ocular Isolates of Pseudomonas aeruginosa.

Background: The prevalence of disinfectant resistance in Pseudomonas aeruginosa is on the rise. P. aeruginosa is the most common bacteria isolated from cases of microbial keratitis. Many multi-purpose contact lens disinfectant solutions are available to decontaminate contact lenses before use and to help reduce the incidence of infections. However, with increasing disinfectant resistance, the effect of multi-purpose disinfectant solutions may diminish. The goal of this study was to examine genes associated with disinfectant resistance in ocular isolates of P. aeruginosa and understand the strain’s susceptibility to different multipurpose disinfectant solutions. Methods: Seven potential disinfectant resistance genes were used in BLASTn searches against the whole genomes of 13 eye isolates of P. aeruginosa. A microdilution broth method was used to examine susceptibility to four different multipurpose disinfectant solutions. Results: All strains possessed the sugE2, sugE3 and emrE (qacE) genes. The sugE1 and qacEdelta1 genes were present in 6/13 isolates. No strains contained the qacF or qacG genes. All tested disinfectant solutions had the ability to kill all test strains at 100% concentration, with some strains being susceptible at 1:8 dilutions of the disinfecting solutions. However, the presence of disinfectant resistance genes was not associated with susceptibility to multi-purpose disinfectants. Conclusion: All four tested contact lens disinfectant preparations are effective against P. aeruginosa isolates regardless of the presence of disinfectant resistance genes.

Chloroquine as a possible disinfection adjunct of disinfection solutions against Acanthamoeba

Acanthamoeba keratitis is commonly encountered by contact lens wearers. Contact lens solution plays an important role in the safe use of contact lenses. The most popular products for disinfecting lenses are multipurpose disinfecting solutions (MPDS). However, almost all MPDS retailed in Korea are ineffective in killing Acanthamoeba. The objective of this study was to determine the possibility of using autophagy inhibitor chloroquine as a disinfecting agent to improve the amoebicidal activity of MPDS against Acanthamoeba, especially the cyst. Amoebicidal effects of eight different MPDSs combined with chloroquine (CQ), an autophagy inhibitor, and their cytotoxicities to human corneal epithelium cells were determined. Almost all MPDS showed strong amoebicidal effect on trophozoites after 8 h of exposure. However, they showed inadequate amoebicidal effect on cysts even after 24 h of exposure. MPDSs combined with 100 μM CQ increased their amoebicidal effects on immature cyst by inhibiting formation of mature cysts. Incubation with 100 μM CQ for 30 min did not have cytotoxicity to human corneal epithelial cells.

Biocompatibility Evaluation of Contact Lens Multipurpose Solutions Through Novel Genotoxicity Assays

Abstract Introduction: Genotoxicity testing is necessary to address potential mutagenic characteristics of pharmaceutical candidates and medical devices depending on their intended use. Adapting such tests to contact lens multipurpose solutions (MPS) may be required due to their antimicrobial nature or to fulfill specific regulatory requirements. We describe a novel methodology for genotoxicity and biocompatibility evaluation of MPS in the context of traditional testing. Materials and Methods: Blink RevitaLens® Multipurpose Disinfecting Solution (MPDS) or contact lens (Acuvue® Advance and Acuvue® 2 brand) extracts were tested by Ames assay and Chromosome Aberration (ChrAb) Assays. A novel procedure for cycling contact lenses in MPDS was developed for testing. Before assays with the Blink RevitaLens MPDS disinfectant ingredient, Alexidine Dihydrochloride (ALX) was diluted for dose-range tests identifying TA100 or Chinese Hamster Ovary cytotoxicity levels to determine the amount of ALX appropriate for each ...

Effects of Lead Phytochemicals of Radix Scutellariae on Acanthamoeba.

Acanthamoeba keratitis (AK), which is associated with noncompliant use of contact lenses, remains difficult to treat due to delayed diagnosis and paucity of therapeutic agents. Although improvements in activity against Acanthamoeba infection have been achieved in disinfecting solutions for soft contact lenses, such modifications have not been extended to those for special rigid gas permeable (RGP) contact lenses, which are increasingly used for myopia control in children. Phytochemicals present in herbs used for traditional Chinese medicine may be effective as therapeutic or preventive agents. The purpose of this study was to investigate amoebicidal properties of lead phytochemicals of Radix scutellariae alone and in combination with multipurpose (disinfecting) solutions (MPS) for RGP lenses. Viability of Acanthamoeba castellani and A. polyphaga trophozoites was determined following exposure to four phytochemicals: baicalin, baicalein, wogonoside, and oroxylin A and both alone and in combination with four RGP MPS, using a modified stand-alone technique. As individual agents, wogonoside and oroxylin A showed highest activity against A. castellani and A. polyphaga trophozoites, respectively. For both organisms, the combination of baicalein and oroxylin A was superior. Effectiveness of MPS alone did not exceed 0.27 log reduction, but addition of combined baicalein and oroxylin A resulted in 0.92 and 0.64 log reductions of A. castellani and A. polyphaga, respectively. The combination of baicalein and oroxylin A enhanced the activity of MPS for RGP contact lenses against trophozoites of two pathogens, A. castellani, and A. polyphaga, and offers a potential therapeutic and/or preventative agent for AK.

Efficacy of Korean Multipurpose Contact Lens Disinfecting Solutions against Acanthamoeba castellanii.

Acanthamoeba keratitis has been increasing in recent years. Main risk factors are contact lens wear and their cleaning solutions. Most contact lens wearers use multipurpose disinfecting solutions (MPDS) for cleansing and disinfecting microorganisms because of its convenience. We determined amoebicidal effects of MPDS made in Korea and their cytotoxicity on human corneal epithelium cells. Fifteen commercial MPDS (A to O) were tested for their amoebicidal effects on Acanthamoeba castellanii trophozoites and cysts by using a most probable number (MPN) technique. Among them, 7 kinds of MPDS showed little or no amoebicidal effects for 24 hr exposure. Solutions A, B, G, H, L, and O showed positive amoebicidal effects, and solutions M and N killed almost all trophozoites and cysts after 24 hr exposure. However, 50%-N solution showed 56% cytotoxicity on human corneal epithelial cells within 4 hr exposure, and 50%-O solution also showed 62% cytotoxicity on human cells within 4 hr exposure. Solution A did not show any cytotoxicity on human cells. These results revealed that most MPDS made in Korea were ineffective to kill Acanthamoeba. The solutions having amoebicidal activity also showed high levels of cytotoxicity on human corneal epithelial cells. New formulations for improved MPDS that are amoebicidal but safe for host cells are needed to prevent Acanthamoeba keratitis.

Antimicrobial Efficacy of Multipurpose Disinfecting Solutions in the Presence of Contact Lenses and Lens Cases.

Objective:The aim of this study was to use antimicrobial efficacy endpoint methodology to determine compatibility of multipurpose disinfecting solutions (MPSs), lens cases, and hydrogel lenses for disinfection (AEEMC) against International Organization for Standardization (ISO)–specified microorganisms and clinical ocular isolates of Stenotrophomonas maltophilia.Methods:Six MPSs (PQ/Aldox 1, 2, and 3; PQ/Alexidine; PQ/PHMB; and PHMB) were challenged against ISO-specified microorganisms and S. maltophilia using the AEEMC test. AEEMC tests were performed with and without balafilcon A, etafilcon A, and senofilcon A lenses in lens cases with organic soil. Exposure times included disinfection time (DT) and 24 hr. Additionally, all six MPSs were challenged with two strains of S. maltophilia, based on the ISO Stand-alone test.Results:The efficacy against bacteria for PQ/Aldox and PQ/Alexidine MPSs was not diminished by the presence of lenses. The efficacy of PQ/PHMB and PHMB MPSs against Serratia marcescens was significantly reduced compared with the no-lens control at DT for at least one lens type. The PHMB MPS with lenses present also demonstrated reduced efficacy against Staphylococcus aureus at DT versus the control. PQ/Aldox MPSs retained activity against Fusarium solani with lenses present; however, all other test MPSs demonstrated reduced F. solani efficacy at DT with lenses present. With lenses, all MPSs showed reduced efficacy against Candida albicans.Conclusions:AEEMC antimicrobial efficacy test results vary based on challenge microorganism, contact lenses, and MPS biocide systems. This study highlights the importance of evaluating MPSs for compatibility with lenses and lens cases.

Risk Factors for Contact Lens-Related Microbial Keratitis: A Case-Control Multicenter Study.

The most feared complication of contact lens (CL) wear is microbial keratitis (MK), even though its incidence remains low. This study aimed to identify the risk factors of CL-related MK in a large, prospective, multicenter case-control study. A multicenter case-control study was designed. The CL-related MK subpopulation (Case) was compared with healthy CL wearers (Control) using a 52-item anonymous questionnaire designed to determine subject demographics and lens wear history. Univariate and multivariate logistic regression analyses were performed to compare both groups. The study enrolled 499 cases and 508 controls. The risk factors associated with the greatest increased odds of CL-related MK were as follows: using disinfecting solution more than 3 months (odds ratio [OR]=1.94), cosmetic CL wear and use of multipurpose disinfection solution (1.37 each), overnight wear, and soft lens use (OR=1.24 each). The protective factors associated with the greatest reduction in OR were fitting by an ophthalmologist (OR=0.73) and hyperopia versus myopia (OR=0.75). The infectious determinants were linked to the type of lenses, hygiene routine, CL handling, disinfecting solution, and storage case. This study aimed to highlight the increasingly CL-related MK, which likely occurs because of lack of patient information regarding basic rules of hygiene and CL care and handling.

Effect of the osmolarity change in multipurpose solutions induced by an improper contact lens case cleaning procedure.

To determine whether variations in multipurpose disinfecting solution (MPDS) storage osmolarity from inappropriate contact lens (CL) case cleaning affect ocular surface integrity and wearer comfort. There were twenty contact lens cases (study CLCs) in the study group. Ten were filled with ReNu Multiplus(®) and 10 with SoloCare Aqua™ (MPDS-1 and -2, respectively) and kept closed for 8h; the cases were then emptied and kept open for air-drying for 16h. This procedure was carried out every day for two months. Storage solution osmolarity was measured on days 0, 15, 30, 45 and 60. Ten subjects were then fitted with both month-old lenses stored in the study CLCs and with new lenses stored in new cases with fresh solution for 24h (control CLCs). Symptoms, tear osmolarity and percentage of subjects whose conjunctival hyperaemia and ocular surface staining scores changed were determined after 1h of wear. Study CLC osmolarity increased in both solutions after two months (p<0.05). For MPDS-1 there were differences in stinging between study CLCs and control CLCs after 10min of CL wear (p=0.04), and in comfort after 10 (p=0.035) and 60min wear (p=0.042). Significant (p<0.05) differences between study CLC and control CLC groups were also found for MPDS-2 in limbal hyperaemia (study: 50% change; control: 0% change) and bulbar and corneal staining (study: 80% change; control: 20% change). The stored-MPDS osmolarity increase caused by air-drying the CLCs could affect the ocular surface. This increase might reduce lens wear comfort.

Effect of Daily Contact Lens Cleaning on Ocular Adverse Events during Extended Wear.

The purpose of the study was to assess what effect daily cleaning of contact lenses with a multipurpose disinfection solution (MPDS), during 30 nights extended wear, would have on contact lens-related adverse events. This was a prospective, open-label, randomized, controlled, parallel-group, 3-month clinical study in which 193 participants were dispensed with lotrafilcon A silicone hydrogel lenses for a 30-day extended-wear schedule and with lenses replaced monthly. Participants were randomized to a control or test group. Test subjects were required to remove lenses daily after waking, clean them with the MPDS, and reinsert the lenses. Control subjects wore lenses without removal for 30 days extended wear. Handling-related lens contamination was assessed at the baseline visit. There was no significant difference between the test and control groups for the incidence of significant corneal infiltrative events (1.3 vs. 4.9%, p = 0.368), total corneal infiltrative events (2.6 vs. 4.9%, p = 0.682), or mechanical events (1.3 vs. 2.5%, p = 1.00). The test group had greater corneal staining (p < 0.047) and fewer mucin balls (p = 0.033). Handling-related lens contamination (unworn lenses) resulted in isolation of Gram-positive bacteria from 92.5% of test lenses compared with 87.5% of control lenses (p = 0.712). Gram-negative bacteria were isolated from 5% of test subjects compared with 2.5% of control subjects (p = 1.00). Fungus was isolated from 2.5% of subjects in both the test and control groups (p = 1.00). The intervention of daily morning cleaning of the lens surface with an MPDS during extended wear did not significantly influence the incidence of adverse events.

Disinfectant efficacy of soft contact lens care system containing povidone iodine

Disinfectant efficacy of soft contact lens care system containing povidone iodine

Susceptibility of Stenotrophomonas maltophilia clinical isolates to antibiotics and contact lens multipurpose disinfecting solutions.

To determine the susceptibility of Stenotrophomonas maltophilia to various antibiotics and contact lens multipurpose disinfecting solutions. Forty S. maltophilia strains from contact lens cases, contact lenses, or eye swabs of contact lens wearers including 27 asymptomatic wearers and 13 keratitis patients were examined for their susceptibility to different antibiotics, using a disc diffusion assay, and to multipurpose disinfecting solutions using a broth microdilution method. Certain strains were resistant to aztreonum (15%), imipenem (93%), chroramphenicol (13%), and cefepime (8%). Two of those strains were multidrug resistant. All strains were sensitive to trimethoprim-sulfamethoxazole, tigecycline, ceftazidime, and fluoroquinolones. Overall, the minimum inhibitory concentration (MIC) for all strains was significantly higher (P < 0.05) for AQuify (50% dilution) and OPTI-FREE RepleniSH (25%) than all other multipurpose contact lens disinfecting solutions (MPDS) (3%-14%, except RepleniSH versus MeniCare Soft [14%]). AQuify, OPTI-FREE RepleniSH, and MeniCare Soft had significantly higher minimum bactericidal concentrations (undiluted MPDS) than other disinfecting solutions (P < 0.05). The Australian ocular isolates of S. maltophilia remain susceptible to trimethoprim-sulfamethozole, tigecycline, and most fluoroquinolones. However, the isolates showed resistance to certain multipurpose disinfecting solutions.