UNASSIGNED: The emergence of disinfectant resistance has become a severe threat due to reduced effectiveness. This study was undertaken to determine how bacteria adapt to survive exposure to disinfectants in the busiest section of a tertiary care hospital in Varanasi, India.
UNASSIGNED: Four isolates (two Klebsiella pneumoniae, Kp1 and Kp2; two Pseudomonas aeruginosa, Pa1 and Pa2) were obtained from chlorhexidine (CHX)-based handwash during microbiological surveillance of \"in-use disinfectants\" in hospital. Six disinfectants [4% CHX, 2% glutaraldehyde, 7.5% hydrogen peroxide, 1% sodium hypochlorite and 0.1% benzalkonium chloride (BAC), and 70% ethyl alcohol] were tested against these four isolates to determine minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Antibiotic profile, change in MIC on exposure to disinfectants and biofilm formation in the presence and absence of disinfectants was studied. Whole genome sequencing (WGS) was done to identify the resistance mechanisms.
UNASSIGNED: The isolates showed the highest MBC/MIC ratio (4) against glutaraldehyde. Exposure to supra-inhibitory concentration of BAC for 21 days resulted in doubling of MIC/MBC. The majority (75%) of the isolates were multidrug resistant. All the isolates were strong biofilm producers. The reduction rate of biofilm formation decreased with an increase in the concentration of disinfectants (p = 0.05 for BAC). WGS revealed multiple AMR genes including bla DIM-1, disinfectant-resistant gene and efflux pump genes.
UNASSIGNED: The study emphasized the various adaptation strategies of these isolates for survival in disinfectant environment, thus posing a huge challenge for their control in the hospital environment.

Dry eye disease (DED) is an ophthalmic disease associated with poor quality and quantity of tears, and the number of patients is steadily increasing. The aim of this study was to determine plasma and urine metabolites obtained from DED scopolamine animal model where dry eye conditions (DRY) are induced. It was also of interest to examine whether DED (scopolamine) rat model was exacerbated by treatment with benzalkonium chloride (BAC). Subsequently, plasma and urine metabolites were analyzed using liquid chromatography (LC) and gas chromatography (GC)-mass spectrometry (MS), respectively. Data demonstrated that DED indicators such as tear volume, tear breakup time (TBUT), and corneal damage in the DED groups (DRY and BAC group) differed from those of control (CON). Similar results were noted in inflammatory factors such as interleukin (IL-1β), IL-6, and tumor necrosis factor (TNF)-α. In the partial least squares-discriminant analysis (PLS-DA) score plots, the three groups were distinctly separated from each other. In addition, the related metabolites were also associated with these distinct separations as evidenced by 9 and 14 in plasma and urine, respectively. Almost all of the selected metabolites were decreased in the DRY group compared to CON, and the BAC group was lower than the DRY. In plasma and urine, lysophosphatidylcholine/lysophosphatidylethanolamine, organic acids, amino acids, and sugars varied between three groups, and these metabolites were related to inflammation and oxidative stress. Data suggest that treatment with scopolamine with/without BAC-induced DED and affected the level of systemic metabolites involved in inflammation and oxidative stress.

Benzalkonium chloride (BAC) is a broad-spectrum antibacterial agent that possesses cleaning and bactericidal properties, but impact of BAC on wellbeing of aquatic organisms remains uncertain. Consequently, in this current study, we have examined the immunotoxic potential of BAC in zebrafish embryos, thus marking it as the pioneering effort in this field. According to the findings, zebrafish embryos exposed to BAC exhibited a decline in yolk area that varied with the concentration, along with a significant decrease in the count of neutrophils, macrophages, red blood cells, and thymus T-cells. We observed significantly up-regulated expression of immune-related signaling genes such as cxcl-c1c, il-8, tir4 and inf-γ, but expression of nf-κb was downregulated. In addition, we observed a marked reduction in the number of hematopoietic stem cells in zebrafish larvae after BAC exposure, which could be the result of oxidative stress-mediated apoptosis. We found that compared with the control group, the number of red blood cells in juvenile zebrafish in BAC-exposure group was significantly down-regulated, which could be attributed to hematopoietic stem cell defect. Astaxanthin restored immune cells and hematopoietic stem cells after BAC exposure, whereas Inhibitor of Wnt Response-1(IWR-1) restored neutrophils after BAC exposure. The research findings demonstrated that exposure to BAC displayed harmful effects on the development and immune system of zebrafish embryos. These effects might be associated with alterations in reactive oxygen species(ROS) levels and activation of the Wnt signaling pathway caused by BAC.

This study aimed to investigate the toxic effects of benzalkonium chloride (BAC) on Oreochromis mossambicus, a freshwater fish species. Probit analysis was used to determine the lethal concentration (LC50) of BAC for different exposure periods (24, 48, 72, and 96 h). The viability of fish exposed to BAC was assessed using the general threshold survival models (GUTS) and confirmed with relevant datasets to evaluate model accuracy. Experimental groups of fish were exposed to BAC concentrations equivalent to 10% and 20% of the 96-h LC50 for 45 days. The study revealed significant alterations in various parameters during sublethal BAC exposure. These effects included decreased specific growth rate (SGR), red blood cell count (RBC), hemoglobin (Hb) concentration, hematocrit (Ht) value, plasma protein, and albumin levels, as well as acetylcholinesterase (AChE) activities in both gills and liver. Additionally, an increase in gastrosomatic index (GSI), feed conversion ratio (FCR), plasma glucose and creatinine concentrations, alanine aminotransferase (ALT), aspartate aminotransferase (AST) enzymatic activities, catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA) levels were observed in the exposed fish\'s gills and liver. Furthermore, the study found that glutathione S-transferase (GST) and glutathione peroxidase (GPx) levels initially increased and then decreased in both gills and liver after exposure to BAC. Correlation matrix analysis, multivariate multiple regression (MMR), canonical correspondence analysis (CCA), integrated biomarker response (IBR), and biomarker response index (BRI) were utilized to assess the impact of BAC on fish, highlighting significant effects on multiple biomarkers in O. mossambicus following surfactant exposure. Thus, the study provides valuable insights into the toxic effects of BAC on this fish species, emphasizing the importance of monitoring such pollutants in aquatic environments.

OBJECTIVE: Benzalkonium chloride (BAC) is commonly used as a preservative in ophthalmic medications, despite its potential to induce chemical injury. Extensive research has demonstrated that BAC can lead to adverse effects, including injuries to the ocular surface. Our study aimed to elucidate the underlying mechanism of necroptosis induced by BAC.
METHODS: Human corneal epithelial (HCE) cells and mouse corneas were subjected to chemical injury, and the necrostatin-1 (Nec1) group was compared to the dimethylsulfoxide (DMSO) group. The extent of damage to HCE cells was assessed using CCK-8 and flow cytometry. Hematoxylin and eosin staining, as well as fluorescein sodium staining, were used to detect and characterize corneal injury. The activation of inflammatory cytokines and necroptosis-related proteins and genes was evaluated using Western blotting, immunofluorescence staining, and quantitative RT‒PCR.
RESULTS: In our study, the induction of necroptosis by a hypertonic solution was not observed. However, necroptosis was observed in HCE cells exposed to NaOH and BAC, which activated the receptor-interacting protein kinase 1 (RIPK1) - receptor-interacting protein kinase 3 (RIPK3) - mixed lineage kinase domain-like protein (MLKL) signaling pathway. In mouse corneal tissues, BAC could induce necroptosis and inflammation. The administration of Nec1 mitigated the inflammatory response and ocular surface damage caused by BAC-induced necroptosis in our experimental models. Furthermore, our in vivo experiments revealed that the severity of necroptosis was greater in the 3-day group than in the 7-day group.
CONCLUSIONS: Necroptosis plays a role in the pathological development of ocular surface injury caused by exposure to BAC. Furthermore, our study demonstrated that the administration of Nec1 could mitigate the pathological effects of necroptosis induced by BAC in clinical settings.

Ocular surface disease (OSD) is a complex condition that can cause a range of symptoms (e.g, dryness, irritation, and pain) and can significantly impact the quality of life of affected individuals. Iatrogenic OSD, a common finding in patients with glaucoma who receive chronic therapy with topical ocular antihypertensive drugs containing preservatives such as benzalkonium chloride (BAK), has been linked to damage to the ocular surface barrier, corneal epithelial cells, nerves, conjunctival goblet cells, and trabecular meshwork. Chronic BAK exposure activates inflammatory pathways and worsens symptoms, compromising the success of subsequent filtration surgery in an exposure-dependent manner. In eyes being treated for glaucoma, symptomatic treatment of OSD may provide some relief, but addressing the root cause of the OSD often necessitates reducing or, ideally, eliminating BAK toxicity. Strategies to decrease BAK exposure in patients with glaucoma encompass the use of preservative-free formulations or drugs with alternative and less toxic preservatives such as SofZia®, Polyquad, potassium sorbate, or Purite®. Though the benefits of these alternative preservatives are largely unproven, they might be considered when financial constraints prevent the use of preservative-free versions. For patients receiving multiple topical preserved drugs, the best practice is to switch to nonpreserved equivalents wherever feasible, regardless of OSD severity. Furthermore, nonpharmacological approaches, including laser or incisional procedures, should be considered. This review explores the effects of BAK on the ocular surface and reviews strategies for minimizing or eliminating BAK exposure in patients with glaucoma in order to significantly improve their quality of life and prevent complications associated with chronic exposure to BAK.

BACKGROUND: Primary open-angle glaucoma (POAG), often associated with increased intraocular pressure (IOP), can lead to permanent damage of the optic nerve, concomitant visual field loss, and blindness. Latanoprost, a prostaglandin F2α analogue, reduces IOP and is used to treat glaucoma. In this clinical trial, we evaluated the efficacy of Latanoprost Polpharma, a generic preservative-free latanoprost 0.05 mg/ml eye drops solution, in lowering IOP when compared to the originator Xalatan® (latanoprost 0.005% ophthalmic solution, Pfizer).
METHODS: This was a Phase III, multicentre, randomized, investigator-masked, cross-over, comparative, non-inferiority trial carried out in 5 sites in Hungary and Russia. The primary endpoint was to evaluate the non-inferiority of the test product when compared to the reference product with respect to the differences in the mean diurnal IOP on Day 1 (baseline) and Day 29. The secondary endpoints included efficacy, ocular tolerance, safety, and usability. We recruited adult patients (18-75 years) with open-angle glaucoma or ocular hypertension.
RESULTS: Forty-nine patients were randomised and received at least one dose of the test or reference product. A virtually identical reduction of the mean diurnal IOP of 7.04 ± 2.14 mmHg or 7.17 ± 2.11 mmHg was found after treatment with test or reference product, respectively (N = 44). In the intention to treat analysis, the reduction was 7.29 ± 2.53 mmHg (95% CI: 6.55-8.04) or 7.43 ± 2.78 mm Hg (95%CI: 6.61-8.24) after treatment with test or reference product, respectively (N = 47). There were no serious adverse events.
CONCLUSIONS: Latanoprost Polpharma was shown to be non-inferior to Xalatan®. Both investigational products were equally well tolerated and safe. The data show a trend in favour of the test product with regards to the severity of hyperaemia and to the velocity of remission of ocular discomfort. Latanoprost Polpharma, being preservative-free, also avoids the cytotoxicity of benzalkonium chloride, the side effects of which may affect patient compliance and lower the quality of life.
BACKGROUND: The study had the ethical and regulatory approval from the National Institute of Pharmacy and Nutrition (OGYEI, OGYEI/41,779- 11/2018) and the Ethics Committee for Clinical Pharmacology (KFEB) of Hungary and from the Ministry of Healthcare of the Russian Federation (MOH of Russia) prior to the beginning of the study (642/25.12.2018) (clinical trial identification number: 848,300,144/0103/1 - POP03; IND number/EudraCT number: 2018-001727-39).

Antimicrobial tolerance is a significant concern in the food industry, as it poses risks to food safety and public health. To overcome this challenge, synergistic combinations of antimicrobials have emerged as a potential solution. In this study, the combinations of two essential oil constituents (EOCs), namely carvacrol (CAR) and eugenol (EUG), with the quaternary ammonium compounds (QACs) benzalkonium chloride (BAC) and didecyldimethylammonium chloride (DDAC) were evaluated for their antimicrobial effects against Escherichia coli and Bacillus cereus, two common foodborne bacteria. The checkerboard assay was employed to determine the fractional inhibitory concentration index (FICI) and the fractional bactericidal concentration index (FBCI), indicating the presence of bactericidal, but not bacteriostatic, synergy in all QAC-EOC combinations. Bactericidal synergism was clearly supported by Bliss independence analysis. The bactericidal activity of the promising synergistic combinations was further validated by time-kill curves, achieving a >4-log10 reduction of initial bacterial load, which is significant compared to typical industry standards. The combinations containing DDAC showed the highest efficiency, resulting in the eradication of bacterial population in less than 2-4 h. These findings emphasize the importance of considering both bacteriostatic and bactericidal effects when evaluating antimicrobial combinations and the potential of EOC-QAC combinations for sanitization and disinfection in the food industry.

Quaternary ammonium compounds have served as a first line of protection for human health as surface disinfectants and sanitizers for nearly a century. However, increasing levels of bacterial resistance have spurred the development of novel QAC architectures. In light of the observed reduction in eukaryotic cell toxicity when the alkyl chains on QACs are shorter in nature (≤10 C), we prepared 47 QAC architectures that bear multiple short alkyl chains appended to up to three cationic groups, thus rendering them \"bushy-tailed\" multiQACs. Antibacterial activity was strong (often ~1-4 μM) in a varied set of bushy-tailed architectures, though observed therapeutic indices were not significantly improved over QAC structures bearing fewer and longer alkyl chains.

A new method was established for the simultaneous analysis of four homologous benzalkonium chlorides (dodecyldimethylbenzyl ammonium chloride, tetradecyldimethylbenzyl ammonium chloride, hexadecyldimethylbenzyl ammonium chloride, and octadecyldimethylbenzyl ammonium chloride) in compound chemical disinfectants using non-aqueous capillary electrophoresis (CE) based on a micellar electrokinetic chromatography mode with direct ultraviolet detection. The separation was performed on an uncoated fused quartz capillary with a total length of 60.2 cm and a diameter of 25 μm. The separation buffer consisted of a mixture of methanol/acetonitrile (60:40, v/v) containing 70 mmol/L sodium acetate, 60 mmol/L trifluoroacetic acid and 20 mmol/L sodium dodecyl sulfate. The sample buffer was a methanol solution containing only 2 mmol/L trifluoroacetic acid. The separation voltage was set at 8 kV with a working current of approximately 2.3 μA. The detection wavelength was 214 nm. Under optimal conditions, the limit of detection and limit of quantification for these four benzalkonium chlorides (BACs) were 1.0 mg/L and 5.0 mg/L, respectively. Good linearities were observed in the concentration ranges from 5.0 to 100.0 mg/L, with correlation coefficients above 0.999 for all compounds. The recoveries of these four BACs ranged from 92.5 % to 109.1 % with relative standard deviations below 4.7 %. With the new method, all four BACs could be analyzed in a single injection. In contrast, the aqueous CE method in the National Standard GB/T 26369-2020 only allowed for the simultaneous analysis of the first three homologous. The new method demonstrated the improved peak shape compared to the aqueous CE method and then was successfully applied to the analysis of 19 commercially available samples, such as object table disinfectants, hand sanitizers, and disinfectant wipes, which claimed to contain quaternary ammonium compound. The results obtained using the new method were compared with those of the aqueous CE of the National Standard Method, and no statistically significant differences were observed. The new method is simple in pre-treatment and provides accurate results, making it highly suitable for routine analysis.