Comparison Between Moxifloxacin and Chloramphenicol for the Treatment of Bacterial Eye Infections.

Background: Moxifloxacin is a bactericidal methoxyquinolone used for the treatment of conjunctivitis and prophylactic therapy in cataract and refractive surgeries. Chloramphenicol is a bacteriostatic organochlorine introduced into clinical practice in 1948 and used mainly in topical preparations because of its known toxicity. Objectives: The study aimed to evaluate the in vitro antibacterial effect and the ocular cytotoxicity of these broad-spectrum antibiotics. Methods: Antimicrobic activity was tested on 4 bacteria strains (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis), and determined through calculation of MIC and half inhibitory concentration for each microorganism. Antibacterial activity was determined by microdilution method after 24 hours' incubation with 2-fold serial dilutions (2.5 mg/mL to 4.883 µg/mL) of moxifloxacin and chloramphenicol. Disk diffusion test were performed according to European Committee on Antimicrobial Susceptibility Testing methodology. Biofilm formation inhibition and biofilm eradication concentration assay were conducted for P aeruginosa and S epidermidis using the microdilution method. Cytotoxicity of antibiotics was evaluated by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) colorimetric assay on human corneal cell. Results: Cytotoxicity of antibiotics was evaluated on human epithelial corneal cells after 4 hours treatment by viability assay. Results showed that corneal cell viability was significantly higher after moxifloxacin treatment compared with chloramphenicol (P < 0.01). Moxifloxacin is characterized by a significantly lower MIC and half inhibitory concentration values and a larger inhibition zone for all the strain tested, with high performance in controlling gram-negative growth, compared with chloramphenicol. Moreover, moxifloxacin showed higher activity compared with chloramphenicol in the inhibition of biofilm formation and in the disruption of biofilm, especially against S epidermidis biofilm. Conclusions: The lower corneal cell toxicity and the broader spectrum of antibacterial activity observed with moxifloxacin suggests its use in ophthalmic solution for the treatment of bacterial eye infections.

Ozonated Oil in Liposome Eyedrops Reduces the Formation of Biofilm, Selection of Antibiotic-Resistant Bacteria, and Adhesion of Bacteria to Human Corneal Cells.

The recent attention to the risk of potential permanent eye damage triggered by ocular infections has been leading to a deeper investigation of the current antimicrobials. An antimicrobial agent used in ophthalmology should possess the following characteristics: a broad antimicrobial spectrum, prompt action even in the presence of organic matter, and nontoxicity. The objective of this study is to compare the antimicrobial efficacy of widely used ophthalmic antiseptics containing povidone-iodine, chlorhexidine, and liposomes containing ozonated sunflower oil. We determined the minimum inhibitory concentration (MIC) on various microbial strains: Staphylococcus aureus (ATCC 6538), methicillin-resistant Staphylococcus aureus (ATCC 33591), Staphylococcus epidermidis (ATCC 12228), Pseudomonas aeruginosa (ATCC 9027), and Escherichia coli (ATCC 873). Furthermore, we assessed its efficacy in controlling antibiotic resistance, biofilm formation, and bacterial adhesion. All three antiseptic ophthalmic preparations showed significant anti-microbicidal and anti-biofilm activity, with the liposomes containing ozonated sunflower oil with the highest ability to control antibiotic resistance and bacteria adhesion to human corneal cells.

Non-classical HLA class I molecules and their potential role in viral infections.

Human Leukocyte Antigens (HLA) are classified in three different classes I, II and III, and represent the key mediators of immune responses, self-tolerance development and pathogen recognition. Among them, non-classical subtypes (HLA-Ib), e.g. HLA-E and HLA-G, are characterize by tolerogenic functions that are often exploited by viruses to evade the host immune responses. In this perspective, we will review the main current data referred to HLA-G and HLA-E and viral infections, as well as the impact on immune response. Data were selected following eligibility criteria accordingly to the reviewed topic. We used a set of electronic databases (Medline/PubMed, Scopus, Web of Sciences (WOS), Cochrane library) for a systematic search until November 2022 using MeSH keywords/terms (i.e. HLA, HLA-G, HLA-E, viral infection, SARS-CoV-2, etc.…). Recent studies support the involvement of non-classical molecules, such as HLA-E and HLA-G, in the control of viral infection. On one side, viruses exploit HLA-G and HLA-E molecule to control host immune activation. On the other side, the expression of these molecules might control the inflammatory condition generated by viral infections. Hence, this review has the aim to summarize the state of art of literature about the modulation of these non-classical HLA-I molecules, to provide a general overview of the new strategies of viral immune system regulation to counteract immune defenses.

Evaluation of the microbiological and chemical aspects of autochthonous wild snails in Sardinia.

This study was conducted to acquire knowledge on the epidemiology and ecology of some zoonotic agents in snails. Chemical and microbiological analysis was carried out on 46 samples of snails belonging to the species of Helix aspersa and Helix (Eobania) vermiculata. The association between heavy metals and wild snails, a native consumer product in the Region of Sardinia, was determined. The molecular characterisation of Listeria monocytogenes virulence genes has shown a genetic profile that deserves more attention for the improvement of surveillance and risk prevention. Specimens of H. vermiculata showed higher concentrations of cadmium (M=0.80±0.56 mg/kg) than H. aspersa (M=0.61±0.17 mg /kg). A further objective was to determine whether the samples showed significant differences from the point of view of secretion characterisation, in terms of protein content, and to identify species-specific correlations and possible relationships with the environment. The presence of Salmonella enterica sub.sp houtenae (6,14: z4, z23) and Salmonella enterica subsp diarizonae (47: k: e, n, z15) (1 sample), Listeria monocytogenes (2 samples) with Molecular characterization of virulence genes together with the measurement of heavy metals in samples of wild snails has shown a health and hygiene profile that would deserve greater attention for the improvement of the surveillance and prevention of microbiological and chemical risk in such products which currently show a tendency towards increase in consumption.

GlicoPro, Novel Standardized and Sterile Snail Mucus Extract for Multi-Modulative Ocular Formulations: New Perspective in Dry Eye Disease Management.

This study aimed to evaluate the mucoadhesive and regenerative properties of a novel lubricating multimolecular ophthalmic solution (GlicoPro®) extracted from snail mucus and its potential anti-inflammatory and analgesic role in the management of dry eye disease (DED). GlicoPro bio-adhesive efficacy was assessed using a lectin-based assay, and its regenerative properties were studied in a human corneal epithelial cell line. In vitro DED was induced in human corneal tissues; the histology and mRNA expression of selected genes of inflammatory and corneal damage biomarkers were analyzed in DED tissues treated with GlicoPro. A higher percentage of bio-adhesivity was observed in corneal cells treated with GlicoPro than with sodium hyaluronate-based compounds. In the scratch test GlicoPro improved in vitro corneal wound healing. Histo-morphological analysis revealed restoration of cellular organization of the corneal epithelium, microvilli, and mucin network in DED corneal tissues treated with GlicoPro. A significant reduction in inflammatory and ocular damage biomarkers was observed. High-performance liquid chromatography-mass spectrometry analysis identified an endogenous opioid, opiorphin, in the peptide fraction of GlicoPro. In conclusion, GlicoPro induced regeneration and bio-adhesivity in corneal cells; moreover, considering its anti-inflammatory and analgesic properties, this novel ophthalmic lubricating solution may be an innovative approach for the management of DED.

Design of Liposomes Carrying HelixComplex Snail Mucus: Preliminary Studies.

In recent decades liposomes have been used in different field thanks to their ability to act as a vehicle for a wide range of biomolecules, their great versatility and their easy production. The aim of this study was to evaluate liposomes as a vehicle for the actives present in the HelixComplex (HC) snail mucus for topical delivery. Liposomes composed of a mixture of phosphatidylcholine, cholesterol and octadecylamine were prepared with and without HC (empty liposomes) and their biological efficacy was tested by evaluating cell viability and migration. HC-loaded liposomes (LHC) were stable throughout 60 days of observation, and showed interesting effects on wound healing reconstitution. In particular, we observed that 25 µg/mL LHC were already able to induce a higher cell monolayer reconstitution in comparison to the untreated samples and HC treated samples after only 4 h (28% versus 10% and 7%, p = 0.03 and p= 0.003, respectively). The effect was more evident at 24 h in comparison with the untreated control (54% versus 21.2% and 41.6%, p = 0.006 and p = NS, respectively). These results represent a preliminary, but promising, novelty in the delivery strategy of the actives present in the HelixComplex mucus.

HelixComplex snail mucus as a potential technology against O3 induced skin damage.

Mucus form H. aspersa muller has been reported to have several therapeutic proprieties, such as antimicrobial activity, skin protection and wound repair. In this study, we have analyzed H. aspersa mucus (Helixcomplex) bio-adhesive efficacy and its defensive properties against the ozone (O3) (0.5 ppm for 2 hours) exposure in human keratinocytes and reconstructed human epidermis models. Cytotoxicity, tissue morphology and cytokine levels were determined. We confirmed HelixComplex regenerative and bio-adhesive properties, the latter possibly via the characteristic mucopolysaccharide composition. In addition, HelixComplex was able to protect from O3 exposure by preventing oxidative damage and the consequent pro-inflammatory response in both 2D and 3D models. Based on this study, it is possible to suggest HelixComplex as a potentially new protective technology against pollution induced skin damage.

Author Correction: HelixComplex snail mucus exhibits pro-survival, proliferative and pro-migration effects on mammalian fibroblasts.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

HelixComplex snail mucus exhibits pro-survival, proliferative and pro-migration effects on mammalian fibroblasts.

Snail mucus is a mixture of active substances commonly thought to have healthy properties for the treatment of skin disorders. Although snail mucus is an ingredient of several cosmetic and para-pharmaceutic products, a comprehensive characterization of chemical composition and biological effects is still missing. Crude purified extracts from Helix aspersa muller mucus (HelixComplex) were prepared and, after chemical characterization, tested on in vitro experimental models. Differently from what expected, HelixComplex was characterized by the presence of small amounts of glycolic acid and allantoin. By using different in vitro assays on fibroblast cultures, we found that HelixComplex lacked of cytotoxicity, protected cells from apoptosis (p < 0.05) and, importantly, was able to significantly induce cell proliferation and migration through direct and indirect mechanisms. These effects were associated to morphological changes, cytoskeleton re-organization and release of cytokines. In conclusion, our findings suggest that snail mucus biological effects are attributable to cell proliferation and migration, and pave the way for further investigating snail mucus potential as therapeutic agent.