Benzalkonium Research Articles

Bitot-like Spots and Congenital Aniridia: A Case Report

Background: Bitot’s spots, defined as white foamy triangular or round-shaped spots with the base located at the temporal limbus and the apex towards the lateral canthus, were initially associated with vitamin A deficiency (VAD). More recently, Bitot’s spots were also described in patients with normal vitamin A levels, associated with aniridia, dry-eye syndrome and post-thermal or chemical injury, as well as the usage of benzalkonium chloride (BAK) eyedrops. The aim of this article is to present the management of Bitot-like spots in a patient with congenital aniridia. Methods: An 8-year-old female patient with type 1 congenital aniridia, glaucoma, cataract, strabismus, congenital nistagmus and aniridia-associated keratopathy presented with changes in conjunctival appearance. The ophthalmological examination revealed Bitot-like spots with a foamy appearance, triangular shape, temporal location and proximity to the limbus. Further investigations were required in order to identify the cause of Bitot-like spots. Vitamin D deficiency, dry-eye syndrome, birch and Phleum genus pollen allergy were diagnosed. The patient underwent oral medication with vitamin D and topical treatment with steroids eye solution, preservative-free artificial tears and vitamin A ointment. Results: After three months of treatment, we observed the disappearance of the Bitot-like spots. Conclusions: Congenital aniridia, but also its complications such as glaucoma, dry-eye syndrome and the use of benzalkonium chloride topical medication, increases the risk of Bitot-like spots.

Integrated Purification Systems for the Removal of Disinfectants from Wastewater

The efficiency of integrated treatment systems for wastewater generated during the washing of disinfectant production lines was investigated. The high organic load (COD 2000 mg/L, TOC 850 mg/L) and 300 mg/L of toxic benzalkonium chloride (BAC) make wastewater an environmental hazard that requires advanced treatment. Initial tests on model BAC solutions (in concentrations corresponding to those found in wastewater), using nanofiltration and ultrafiltration membranes, resulted in up to 70% retention of BAC. To enhance purification, ion exchange and adsorption were introduced as post-membrane treatment steps. In the second part of the investigation, membrane modules characterized by the best separation properties were integrated together with macroporous cation-exchange resin and activated carbon into the purification system to treat wastewater. The research carried out showed that the purification of multicomponent wastewater is a complex task. Significantly lower BAC removal (30%) was achieved in membrane processes compared to the model solutions treatment. In integrated systems, the BAC concentration was reduced to 100 mg/L, TOC to 200 mg/L, and COD to 120 mg/L.

Granular parakeratosis associated with benzalkonium chloride exposure.

Granular parakeratosis associated with benzalkonium chloride exposure.

Degradation of N-methylbenzylamine and N,N-dimethylbenzylamine in anaerobic biological reactors and formation of N-nitrosomethylbenzylamine and N-nitrosodimethylamine during subsequent chloramination.

As water reuse demand increases, wastewater treatment plants must manage byproducts effectively while ensuring safety. The excessive use of benzalkonium chloride disinfectants can lead to the accumulation of benzylamines, such as N-methylbenzylamine (MBA) and N,N-dimethylbenzylamine (DMBA). Biological anaerobic treatment is becoming more popular due to concerns over energy consumption and carbon emissions. Our study examined the biodegradation of MBA and DMBA during anaerobic treatment and their effects on toxic byproduct formation during subsequent chloramination, as well as their impact on bioreactor performance, degradation pathways, and microbial communities. Our results showed that anaerobic bioreactors had minimal impact on overall treatment performance despite the presence of MBA and DMBA. MBA proved resistant to biodegradation, whereas DMBA underwent significant biodegradation. Notably, during chloramination, MBA effluent formed nitroso-MBA with a 1 % molar yield, whereas DMBA effluent had significant N-nitrosodimethylamine formation, with molar yields reaching 10 ± 1 % and 97 ± 7 % of the influent and residual DMBA concentrations. We observed significant differences in microbial communities between the DMBA reactor and the MBA and control reactors. Proposed degradation pathways and the involvement of specific microbial communities were detailed. These findings highlight the importance of thoroughly evaluating biologically treated effluent to manage the risks of toxic byproducts in water reuse.

Solvent Effect on Antimicrobial Hydrophilic Xerogel Coating of Medicinal Leathers in Simulated Industrial Finishing Process.

The hydrophilic character and the protection against pathogen proliferation are the most pivotal characteristics of leathers intended for medical purposes. To achieve these goals, dispersions of TiO2 particles incorporating three different formulations of biomimetically synthesized silica xerogels were tested. Emphasis has been given to the role of single and dual solvents employed. Microbiocide capability was induced by benzalkonium chloride along with silver nanoparticles. Particular emphasis should be given to hyperbranched poly(ethylene imine) multifunctional roles. Spontaneous mineralization of silver ions is realized in the dendritic cavities. In parallel The same polymer acts as a matrix that interacts with the hydrogen bonding network of orthosilicic acid directing and facilitating gel formation. Furthermore, it contributes to both hydrophilicity and antimicrobial properties. Gel formation and subsequent drying occur in the pores of the impregnated TiO2 substrate. The resistance of the leathers to fungal and bacterial infections and biofilm formation was assessed against Klebsiella Pneumoniae,Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis,Staphylococcus aureus, and Candida albicans. The affinity to water was proved by the contact angle method. The proposed treatment is a prospective environmentally friendly replacement to the standard finishing process of medical leathers.

The Influence of the Temperature on Effectiveness of Selected Disinfectants Against African Swine Fever Virus (ASFV)

African swine fever (ASF) is one of the most economically significant diseases of pigs caused by African swine fever virus (ASFV). Due to the lack of effective and safe vaccines, one of the crucial measures to protect farms from the introduction of the ASFV is to apply a strict regime of biosecurity and disinfection. However, in field conditions, the activity of disinfectants may be influenced by temperature, resulting in reduced activity or biodegradation (i.e., freezing or evaporating). The aim of this study was to evaluate the effect of a wide range of temperatures on the virucidal activity of selected active substances commonly used against ASFV. Eight active substances were tested, namely: sodium hypochlorite (1.0%), glutaraldehyde (0.1%), potassium peroxysulfate (0.5%), caustic soda (1.0%), phenol (1.0%), acetic acid (3.0%), benzalkonium chloride (1.0%), and formaldehyde (0.4%). The virucidal activity of each compound was tested at different temperatures (21, −10, and −20 °C for 30 min) and compared to the initial virus titer under the same temperature conditions. Exposure to a range of temperatures did not significantly affect the virucidal efficacy of tested active substances against ASFV. Most of the evaluated substances had reduced virus titers ≥ 4 log10, regardless of the temperature. However, two of them (benzalkonium chloride and acetic acid) were sensitive to sub-zero temperatures, showing a lack of the required 4 log10 virus titer reduction. The conducted study showed that temperature could hamper the virucidal effect of selected substances (i.e., benzalkonium chloride and acetic acid), showing their moderate efficacy against ASFV −10 °C and −20 °C. The results suggest that extreme caution should be taken while applying these substances at sub-zero temperatures. The other substances had no significant sensitivity to the temperature range. Nevertheless, in the case of freezing the agent, insufficient penetration of the disinfected surface may occur, which may result in an ineffective disinfection process.

Formation of a nitrobenzoxadiazole-based yellow fluorophore for the selective spectrofluorimetric determination of the antifungal drug pimaricin in ophthalmic pharmaceutical formulations

Pimaricin (PMR) is a polyene antifungal drug commonly used as the primary medicine for treating fungal keratitis. In this study, a selective and novel spectrofluorimetric method was designed, optimized, and validated to determine pimaricin in its ophthalmic preparations. The method based on the formation of a nitrobenzoxadiazole-based yellow fluorophore upon the reaction of pimaricin with 4-chloro-7-nitro-1,2,3-benzoxadiazole (NBD-Cl). The fluorescence intensity of the fluorophore was measured at the emission wavelength of 538.5 nm (excitation = 473.5 nm). The factors affecting the reaction (reagent volume, alkalinity, reaction temperature, heating time, volume and type of buffer solution, and the dilution solvent) were investigated and optimized. The calculated linear range was 0.25–1.5 µg/mL, and the limits of detection and quantitation for the method were 0.047 and 0.143 µg/mL, respectively. The selectivity of the method for PMR in the presence of the pharmaceutical additive benzalkonium chloride was proved. The established method was successfully applied to determine PMR in its pharmaceutical ophthalmic preparation (Natamycin® ophthalmic drops) with an accuracy of 103.79 ± 1.83%. The proposed method is practical and valuable for its routine application in quality control laboratories for analysis of PMR in its ophthalmic pharmaceutical preparation.

Integrative assessment of mixture toxicity of household chemicals using the toxic unit approach and mode of action.

Household chemicals used daily are often combined, leading to inhalation exposure to mixtures. However, methods for assessing their toxic effects are limited. This study proposes an in vitro assay strategy for evaluating household chemical mixtures using benzalkonium chloride (BKC) and didecyldimethylammonium chloride (DDAC), a common disinfectant. Our approach utilizes the mode of action (MOA) of chemicals by applying toxicity units (TU) to assess the key events related to lung disease, such as reactive oxygen species (ROS) production and cell death. The TU (EC50) values for BKC and DDAC were 3.97 µg/mL and 1.89 µg/mL, respectively, from cytotoxicity results. The TU value of the mixture (5:5 ratio of BKC to DDAC) was calculated as 2.56 µg/mL. Using the OpenMRA platform, the TU values were predicted as 2.37 µg/mL with the concentration addition (CA) model and 11.26 µg/mL with the independent action (IA) model, indicating that the mixture effects were additive and closer to that predicted using the CA model. Both BKC and DDAC induced apoptosis and ROS production in human epithelial cells in a dose-dependent manner, suggesting similar modes of action in promoting cell death. Our results suggested that BKC and DDAC exhibited additive toxicity when combined. Our results demonstrate the utility of the TU-based approach, which combines cytotoxicity, ROS induction, and apoptosis measurements to evaluate mixture toxicity. This approach may be beneficial for assessing early key events relevant to lung diseases and offers a practical strategy for evaluating the inhalation toxicity of household chemical mixtures.

Resorcinol-based Bolaamphiphilic Quaternary Ammonium Compounds.

Quaternary ammonium compounds (QACs) play crucial disinfectant roles in healthcare, industry, and domestic settings. Most commercially utilized QACs like benzalkonium chloride have a common architectural theme, leading to a rise in bacterial resistance and urgent need for novel structural classes. Some potent QACs such as chlorhexidine (CHX) and octenidine (OCT) feature a bolaamphiphilic architecture, comprised of two cationic centers at the molecular periphery and a non-polar region connecting them; these compounds show promise to elude bacterial resistance mechanisms. Inspired by such structures, we synthesized a series of 43 biscationic amphiphilic compounds focused on a resorcinol core, featuring flexibility of linker lengths, alkyl tails, and relative substituent positioning, to study their structure activity relationships (SARs). Antibacterial activity evaluation against a panel of gram-positive and gram-negative strains, including ESKAPE pathogens (A. baumannii,P. aeruginosa), were encouraging, with minimum inhibitory concentrations (MICs) of 0.5-4 μM against all tested strains for select compounds. Ten prepared compounds bearing either 17 or 18 total side chain carbons demonstrated uniformly strong antibacterial activity againstP. aeruginosa(MIC 4-16 μM) and 6 other strains (MIC ≤4 μM), irrespective of cationic spacing.These findings promise to further extend the application of bolaamphiphilic QACs as a novel class of disinfectants.

Adsorption Mechanisms, Ecotoxicity, and Feasibility of Fixed-Bed Application for Benzalkonium Chloride Treatment in Aqueous Matrices

Adsorption Mechanisms, Ecotoxicity, and Feasibility of Fixed-Bed Application for Benzalkonium Chloride Treatment in Aqueous Matrices

Bioequivalence of Preservative-free and Preserved Omidenepag Isopropyl (OMDI) 0.002% Ophthalmic Solutions in Patients with Primary Open-Angle Glaucoma or Ocular Hypertension: Results from the Phase 3 DAISY Study.

Preservative-free omidenepag isopropyl (OMDI) 0.002% ophthalmic solution and OMDI 0.002% ophthalmic solution preserved with benzalkonium chloride were bioequivalent in lowering intraocular pressure after 4 weeks' treatment in patients with primary open-angle glaucoma or ocular hypertension. Preservatives in ophthalmic solutions for lowering intraocular pressure (IOP) are associated with ocular surface disease. The DAISY study evaluated the bioequivalence of preservative-free omidenepag isopropyl (OMDI) 0.002% ophthalmic solution (DE-117B), with OMDI 0.002% preserved with benzalkonium chloride (BAK). DAISY was a phase 3, randomized, evaluator-masked, crossover study conducted in Japan. Patients with primary open-angle glaucoma (POAG) or ocular hypertension (OHT) were randomized 1:1 to DE-117B or OMDI 0.002% for 4 weeks (period 1) then crossed over for 4 weeks (period 2). A 4-week washout preceded both periods. The primary efficacy endpoint was mean diurnal (MD) IOP at Week 4 (combined periods 1 and 2). Bioequivalence between DE-117B and OMDI was defined as 95% confidence interval (CI) between -1.5 and 1.5 for least-squares (LS) mean between-group difference in MD IOP. Adverse events were monitored. Of 74 patients enrolled, 38 were randomized to DE-117B then OMDI, and 36 were randomized to OMDI then DE-117B. DE-117B and OMDI demonstrated bioequivalence at Week 4 (MD IOP±standard deviation in summary statistics: 17.76±2.05mm Hg [DE-117B] vs. 17.71±2.01mm Hg [OMDI]; LS mean±standard error between-group difference in linear mixed effects model: -0.02±0.18mm Hg [95% CI -0.38 to 0.35]). DE-117B versus OMDI was associated with numerically lower overall ocular discomfort. Preservative-free DE-117B and BAK-containing OMDI were bioequivalent in lowering IOP after 4 weeks' treatment in Japanese patients with POAG or OHT. DE-117B was well tolerated with a similar safety profile to OMDI.

Enhancing Biocide Safety of Milk Using Biosensors Based on Cholinesterase Inhibition.

A sensitive and reliable electrochemical biosensor for the detection of benzalkonium chloride (BAC) and didecyldimethylammonium chloride (DDAC), the most commonly used disinfectant biocides in the agri-food industry, is described. Acetylcholinesterase from Drosophila melanogaster (DM AChE) and butyrylcholinesterase from horse serum (BChE) were immobilized by entrapment in a photocrosslinkable polymer on the surface of carbon screen-printed electrodes. Preliminary tests conducted in phosphate buffer showed limits of detection (LODs) of 0.26 µM for BAC using the BChE-based sensor and 0.04 µM for DDAC using the DM AChE sensor. These performances comply with the European regulation for dairy products, which sets a maximum allowable concentration of 0.28 µM for biocides. However, when tested directly in milk samples, a dramatic decrease in the sensitivity of both sensors towards BAC and DDAC biocides was reported. To overcome this problem, a simple liquid-liquid extraction was necessary prior to biosensor measurements, ensuring that the biosensors met European regulatory standards and provided an unbiased response.

Suppressive Mechanism of Benzalkonium Chloride-Bactericidal Activity in the Presence of Oil

Cleaning and sterilization are critical Prerequisite Programs in sanitation management based on HACCP. Most food factories clean and sanitize equipment daily after production using detergents containing benzalkonium chloride (BAC). However, in factories that produce oil and fat-rich foods, it has been discovered that microbes can persist on production equipment. Insufficient cleaning protocols may result in secondary contamination of the final products. Unfortunately, there are limited cleaning agents available that are effective in sterilizing microbes in the presence of oil. Moreover, there is a lack of research on the bactericidal mechanisms and bacterial dynamics in oily environments. In this study, we aimed to reduce bacterial contamination on equipment in such factories by hypothesizing that oil diminishes BAC's bactericidal activity. We conducted lab-scale experiments simulating actual factory conditions to examine the effects of oil on BAC's efficacy. Additionally, we investigated the effect of nonionic surfactants, which are known to enhance BAC's bactericidal activity in oil-free conditions, in the presence of oil. The results showed that BAC's bactericidal activity was significantly reduced in the presence of oil. However, the activity was restored by adding an appropriate amount of secondary alcohol ethoxylate (sec-AE). Microscopic observations revealed that bacteria tended to accumulate at the water/oil interface, suggesting that the oil interface might inhibit BAC from effectively attacking the bacteria. The addition of sec-AE appeared to disperse the bacteria into the water layer, thus restoring BAC's bactericidal activity in the presence of oil. These findings are crucial for improving daily cleaning and sterilization processes in food factories operating in high-oil environments to prevent secondary contamination and enhance food safety.

Research review and transcriptomic insights into Benzalkonium chloride inhalation and disease association.

The widespread use of disinfectants, particularly during the coronavirus disease (COVID-19) pandemic, has significantly increased human exposure to biocides, raising concerns about their potential health risks, especially when inhaled. Benzalkonium chloride (BKC), a quaternary ammonium compound commonly used as a disinfectant and preservative, is a notable example because it is frequently used in household products and medical settings. Despite its broad usage, limited research has been conducted on the respiratory and systemic toxicities of BKC. Here, we conducted a research review of the literature on the respiratory toxicity of BKC. This research review suggests that, while current studies imply that BKC may induce respiratory diseases, the evidence remains insufficient. We employed an aerosol exposure model using primary bronchial epithelial cells to simulate inhalation exposure to BKC in humans. Transcriptomic analysis was performed to identify differentially expressed genes (DEGs) associated with toxicological pathways, including endoplasmic reticulum (ER) stress, apoptosis, mitochondrial dysfunction, and epithelial-mesenchymal transition (EMT). The results were integrated with gene-disease association databases to explore the links between BKC exposure and respiratory diseases such as asthma, chronic obstructive pulmonary disease (COPD), and pulmonary fibrosis. Our study also examined the systemic effects of BKC by analysing the secreted proteins, suggesting possible cardiovascular implications. These findings highlight the need for further research on the health impacts of BKC, particularly its long-term effects, and underscore the importance of regulating its use to minimise the potential health risks associated with exposure via inhalation.

Benzalkonium chloride initiates proinflammatory responses via NLRP3 inflammasome activation

A representative surfactant, benzalkonium chloride (BAC) is used as a disinfectant, but sometimes causes serious side effects, including lung disorders such as interstitial pneumonia. However, its pathogenic mechanisms remain unexplained. In this study, we identified a novel mechanism by which BAC initiates inflammatory responses that may be responsible for its side effects. We firstly investigated whether BAC initiates inflammation, and found that BAC promotes the secretion of the pro-inflammatory cytokine interleukin-1β (IL-1β) but not tumor necrosis factor-α (TNF-α) in macrophages. Interestingly, the IL-1β secretion triggered by the surfactants was completely blocked by the K-ATP channel blocker glibenclamide or the calcium chelating agent 1,2-bis(2-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid (BAPTA)-AM. Moreover, genetic experiments revealed that BAC-dependent IL-1β secretion is mediated by the NLRP3 inflammasome. These results suggest that derangement of ion fluxes associated with the interfacial effects of BAC triggers NLRP3 inflammasome activation and subsequent inflammation. Thus, the NLRP3-dependent mechanisms triggered by BAC may explain the pathogenesis of surfactant-caused adverse effects.

Virucidal activity of olanexidine gluconate against SARS-CoV-2.

Antiseptics have been used for infection control against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Ethanol (EtOH) was found to be effective against SARS-CoV-2, while chlorhexidine gluconate (CHG) was less effective. Therefore, virucidal activity may differ between different classes of antiseptic agents. In this study, the efficacy of antiseptics against SARS-CoV-2 was evaluated, and effective agents for infection control were identified. The following antiseptics were used in this study: 1.5% olanexidine gluconate (OLG); 80% EtOH; 1% sodium hypochlorite (NaClO); 0.2% benzalkonium chloride (BKC); 1% povidone-iodine (PVP-I); 0.5%, 1% and 1.5% CHG; and 0.5% alkyldiaminoethylglycine hydrochloride (AEG). The virucidal activity was evaluated at 0, 0.5, 1, 2 and 3 min according to EN14476. After 0.5 min of exposure, 1.5% OLG, 80% EtOH, 1% NaClO, 0.2% BKC and 1% PVP-I inactivated SARS-CoV-2 below the detection limit. The virus survived in the presence of 0.5% CHG, 1% CHG or 0.5% AEG for 3 min. The virucidal activity of 1.5% CHG was insufficient after 0.5 min of exposure. The results showed that virucidal activity against SARS-CoV-2 differs depending on the class of antiseptic agents used under clean conditions. Despite belonging to the same class of biguanide antiseptics, OLG was more effective against SARS-CoV-2 than CHG.

Can the choice of artificial tears harm patients? A narrative review with learnings from the nordic guidelines

Purpose: To provide an overview of artificial tears marketed in the Nordic countries: Denmark, Sweden, Norway and Finland. Furthermore, this review aims to highlight the different preservatives and other constituents found in artificial tears of the Nordic market, focusing on adverse effects.Methods: Artificial tears appearing in the Nordic Guidelines of “Dry Eye Disease” 2022 edition were included and tables listing their components were created. Based on the preservatives and other constituents found in the artificial tears on the Nordic market, a literature search was conducted to investigate differences and potential adverse effects. Included articles were (i) studies performed on humans in vivo or in vitro human models, (ii) published between 2000‐2023 and (iii) studies focusing on effects, preservatives, toxicity, other constituents, and preservative‐free artificial tears.Results: A total of 66 artificial tears were found on the Nordic market based on the Nordic Guidelines. A large proportion (27 out of 66) of the artificial tears contains preservatives. Ten of these are preserved with benzalkonium chloride (BAK) or cetrimide. After a thorough systematic literature search, 87 articles met the inclusion criteria. A substantial amount of evidence has been found for the toxic effects of BAK and phosphate buffer solutions. There is no evidence of toxic effects of lubricants, osmoprotectants and lipids.Conclusions: The findings of this review highlight the paradoxical fact that many treatments for ocular surface diseases contain toxic preservatives contributing to a possible worse condition. In particular, long‐time toxic effects of BAK may contribute to disease progression.

Factors affecting mass inflow of quaternary ammonium compounds into Japanese sewage treatment plants.

Quaternary ammonium compounds (QACs), ecotoxic organic chemicals linked to multidrug resistance, are being used increasingly, for example to prevent the transmission of infections such as covid-19, in households, hospitals, and industry. To understand the locations, fluctuations, and fractions of QACs entering sewers, we monitored 14 QACs (benzalkonium chloride [BAC]-C8, C10, C12, C14, C16, and C18; dialkyldimethylammonium chloride [DDAC]-C8, C10, and C12; alkyltrimethylammonium chloride [ATAC]-C12, C16, and C18; benzethonium chloride; and cetylpyridinium chloride), and a disinfectant (chlorhexidine) in influent at four Japanese sewage treatment plants (STPs) five times throughout a year. Mass inflows were relatively stable throughout the year, indicating that the recent seasonal covid-19 epidemic did not greatly influence them. The differences in mass inflows among the STPs were normalized successfully by sewered residential population (most relative SDs were <30%), implying households to be the main source. Per-capita mass inflows accounted for 58%-73% of the per-capita consumption of BAC-C12+C14+C16, 28%-59% of that of DDAC-C10, 52%-70% of that of ATAC-C12, 86%-99% of that of ATAC-C16, and 64%-82% of that of ATAC-C18, indicating that a large proportion of their consumption entered sewers. The high contribution of ATAC-C16 agreed with its limited use in primary and secondary industries, little of whose wastewaters enter sewers, whereas the low contribution of DDAC-C10 is attributable to its substantial use in animal husbandry. Our first observation of fractions of QACs entering sewers will advance the management of environmental risks.

Evaluating the Efficacy of Disinfectant Methods against Emydomyces testavorans, a Fungus Associated with Shell Disease in Freshwater Aquatic Turtles.

Emydomyces testavorans is an onygenalean fungus associated with shell and skin lesions in chelonians and is increasingly linked to morbidity and mortality. Effective disinfection methods are a critical component of biosecurity protocols to prevent and manage emydomycosis; however, disinfectant efficacy against E. testavorans is unknown. This study determined the in vitro efficacy of 13 disinfectants across a range of concentrations and exposure times used in veterinary, wildlife, and environmental settings against E. testavorans. Pure E. testavorans culture material was exposed to each disinfectant at manufacturer-recommended concentration and exposure times in triplicate. Disinfectant was removed via centrifugation and cultures were inoculated onto inhibitory media plates, maintained at room temperature (20-22 C), and examined weekly for fungal growth. After 6 wk of incubation, ethanol, Virkon S (active ingredient potassium peroxymonosulfate 21.41%), benzalkonium chloride, and desiccation proved ineffective at completely inhibiting fungal growth. All other agents, including bleach, chlorhexidine, and accelerated hydrogen peroxides, effectively inhibited fungal growth. These data suggest that several effective disinfection options are available for use against E. testavorans. These findings can be used in managed care and field settings to reduce transmission of E. testavorans between turtles through contaminated surfaces and equipment.

The physiochemical properties of artificial tears and their impact on human cultured conjunctival goblet cells

Aims/Purpose: To investigate the cell survival and mucin release (Muc5AC) of human conjunctival goblet cells (GCs) when incubated with preserved and preservative‐free (PF) artificial tears (AT), and to compare the physicochemical properties of these ATs. Ten different ATs were examined, five containing preservatives (benzalkonium chloride (BAK), PolyQuad, and cetrimide) and five preservative‐free.Methods: Primary cultures of human conjunctival GCs were cultivated from donor conjunctiva. After incubation with ATs diluted 1: 7 or 1: 3.5 in culture media for 2 hours, GC survival was analysed using a lactate dehydrogenase assay and compared to a negative control. Mucin release was evaluated after incubation with ATs (1: 7) for 4 hours using an ELISA assay. The pH values, osmolarity, and surface tension of the ATs were also measured.Results: AT (1: 7) preserved with 0.001% BAK and 0.01% cetrimide reduced cell survival by 26% (p &lt; 0.0001) and 19% (p = 0.0304), respectively, compared to a negative control. When diluted 1: 3.5, ATs preserved with 0.005% and 0.006% BAK also significantly decreased cell survival (p = 0.0014 and p &lt; 0.0001, respectively). Preservative‐free ATs did not significantly alter cell survival. Muc5AC release was increased by 0.01% BAK preserved AT (p = 0.0497). The pH values of all ATs varied significantly between different products and were all significantly different from the physiological pH of the tear film (pH = 7.4). None of the ATs were hyperosmolar. PF ATs had a higher surface tension compared to preserved ATs.Conclusions: BAK‐ and cetrimide‐preserved artificial tears induce goblet cell death in a concentration‐dependent manner, potentially exacerbating dry eye disease (DED). Additionally, BAK appears to increase Muc5AC release. Therefore, preservative‐free or PolyQuad‐preserved artificial tears may be more suitable for DED management. The physicochemical properties of these artificial tears vary which can influence their effectiveness.