In vitro assessment of antibacterial and antiviral activity of three copper products after 200 rounds of simulated use.

Copper has well-documented antibacterial effects but few have evaluated it after prolonged use and against bacteria and viruses. Coupons from three copper formulations (solid, thermal coating, and decal applications) and carbon steel controls were subjected to 200 rounds simulated cleaning using a Wiperator™ and either an accelerated hydrogen peroxide, quaternary ammonium, or artificial sweat products. Antibacterial activity against S. aureus and P. aeruginosa was then evaluated using a modified Environmental Protection Agency protocol. Antiviral activity against coronavirus (229E) and norovirus (MNV-1) surrogates was assessed using the TCID50 method. Results were compared to untreated control coupons. One hour after inoculation, S. aureus exhibited a difference in log kill of 1.16 to 4.87 and P. aeruginosa a log kill difference of 3.39-5.23 (dependent upon copper product and disinfectant) compared to carbon steel. MNV-1 demonstrated an 87-99% reduction on each copper surfaces at 1 h and 99% reduction at 2 h compared to carbon steel. Similarly, coronavirus 229E exhibited a 97-99% reduction after 1 h and 90-99% after 2 h. Simulated use with artificial sweat did not hinder the antiviral nor the antibacterial activity of Cu surfaces. Self-sanitizing copper surfaces maintained antibacterial and antiviral activity after 200 rounds of simulated cleaning.

Targeting SARS-CoV-2 Non-Structural Proteins.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an enveloped respiratory ß coronavirus that causes coronavirus disease (COVID-19), leading to a deadly pandemic that has claimed millions of lives worldwide. Like other coronaviruses, the SARS-CoV-2 genome also codes for non-structural proteins (NSPs). These NSPs are found within open reading frame 1a (ORF1a) and open reading frame 1ab (ORF1ab) of the SARS-CoV-2 genome and encode NSP1 to NSP11 and NSP12 to NSP16, respectively. This study aimed to collect the available literature regarding NSP inhibitors. In addition, we searched the natural product database looking for similar structures. The results showed that similar structures could be tested as potential inhibitors of the NSPs.

The Tumor Immune Microenvironment in Clear Cell Renal Cell Carcinoma.

Clear cell renal cell carcinoma (ccRCC) is a type of kidney cancer that arises from the cells lining the tubes of the kidney. The tumor immune microenvironment (TIME) of ccRCC is a complex interplay of various immune cells, cytokines, and signaling pathways. One of the critical features of the ccRCC TIME is the presence of infiltrating immune cells, including T cells, B cells, natural killer cells, dendritic cells, and myeloid-derived suppressor cells. Among these cells, CD8+ T cells are particularly important in controlling tumor growth by recognizing and killing cancer cells. However, the TIME of ccRCC is also characterized by an immunosuppressive environment that hinders the function of immune cells. Several mechanisms contribute to the immunosuppressive nature of the ccRCC TIME. For instance, ccRCC cells produce cytokines such as interleukin-10 (IL-10) and transforming growth factor-beta (TGF-ß), which suppress immune cell activation and promote the differentiation of regulatory T cells (Tregs). Tregs, in turn, dampen the activity of effector T cells and promote tumor growth. In addition, ccRCC cells can express programmed death-ligand 1 (PD-L1), which interacts with the programmed cell death protein 1 (PD-1) receptor on T cells to inhibit their function. In addition, other immune checkpoint proteins, such as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and lymphocyte activation gene 3 (LAG-3), also contribute to the immunosuppressive milieu of the ccRCC TIME. Finally, the hypoxic and nutrient-poor microenvironment of ccRCC can stimulate the production of immunosuppressive metabolites, such as adenosine and kynurenine, which further impair the function of immune cells. Understanding the complex interplay between tumor cells and the immune system in the ccRCC TIME is crucial for developing effective immunotherapies to treat this disease.

Neutralizing antibody responses to the Delta variant of SARS-CoV-2 following vaccination with Ad5-nCoV (CanSino) in the Mexican population.

During the COVID-19 pandemic, the Ad5-nCoV vaccine was applied to the Mexican population before the WHO approved it. In a transversal study, we compare the CanSino vaccine efficacy and a natural SARS-CoV-2 infection in eliciting neutralizing antibodies against the SARS-CoV-2 Delta variant in Guadalajara, Mexico. Participants between 30-60 years were included in the study and classified into three groups: 1) Natural immunity (unvaccinated), 2) Vaccine-induced immunity (vaccinated individuals without a COVID-19 history), and 3) Natural immunity + vaccine-induced immunity. These groups were matched by age and gender. We assessed the ability of individuals' serum to neutralize the Delta variant and compared the results of the different groups using a neutralization test followed by plaque-forming units. Results showed that 39% of individuals' serum with a history of COVID-19 (natural immunity, Group 1) could not neutralize the Delta variant, compared to 33% in vaccinated individuals without COVID-19 (vaccine immunity, Group 2). In contrast, only 7% of vaccinated individuals with a history of COVID-19 (natural + vaccine immunities) could not neutralize the Delta variant. We concluded that the effectiveness of the Ad5-nCoV vaccine to induce neutralizing antibodies against the Delta variant is comparable to that of natural infection (61% vs. 67%). However, in individuals with both forms of immunity (Group 3), it increased to 93%. Based on these results, despite the Ad5-nCoV vaccine originally being designed as a single-dose regimen, it could be recommended that even those who have recovered from COVID-19 should consider vaccination to boost their immunity against this variant.

Use of niosomes for the treatment of intracellular pathogens infecting the lungs.

The delivery of drugs in an encapsulated environment is designed to precisely target specific tissues, avoiding a systemic circulation of the drug. Lungs are organs exposed to the environment with multiple defense barriers. However, many pathogens can still colonize and infect the airways bypassing the hostile environment of the lungs. In more complicated situations, some pathogens have developed strategies to multiply and survive within macrophages, one of the first immune cell responses to clearing infections in mammals. Niosomes are artificial vesicles that can be loaded with drugs, offering an alternative strategy to treat intracellular pathogens as nanocarriers. Members of the mycobacteria genus are intracellular pathogens that have evolved to escape the immunological response, specifically in macrophages, the white cells responsible for the clearance of pathogens. This review analyzed the state-of-the-art niosome synthesis aimed at tackling the problem of intracellular pathogen therapy. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

Advanced biomaterial agent from chitosan/poloxamer 407-based thermosensitive hydrogen containing biosynthesized silver nanoparticles using Eucalyptus camaldulensis leaf extract.

CONTEXT: The emergence of multidrug-resistant (MDR) pathogens poses a significant challenge for global public health systems, increasing hospital morbidity and mortality and prolonged hospitalization. OBJECTIVE: We evaluated the antimicrobial activity of a thermosensitive hydrogel containing bio-synthesized silver nanoparticles (bio-AgNPs) based on chitosan/poloxamer 407 using a leaf extract of Eucalyptus calmadulensis. RESULTS: The thermosensitive hydrogel was prepared by a cold method after mixing the ingredients and left at 4°C overnight to ensure the complete solubilization of poloxamer 407. The stability of the hydrogel formulation was evaluated at room temperature for 3 months, and the absorption peak (420 nm) of the NPs remained unchanged. The hydrogel formulation demonstrated rapid gelation under physiological conditions, excellent water retention (85%), and broad-spectrum antimicrobial activity against MDR clinical isolates and ATCC strains. In this regard, minimum inhibitory concentration and minimum microbial concentration values of the bio-AgNPs ranged from 2-8 µg/mL to 8-128 µg/mL, respectively. Formulation at concentrations <64 µg/mL showed no cytotoxic effect on human-derived macrophages (THP-1 cells) with no induction of inflammation. CONCLUSIONS: The formulated hydrogel could be used in biomedical applications as it possesses a broad antimicrobial spectrum and anti-inflammatory properties without toxic effects on human cells.

Antimicrobial Activity of Filtered Far-UVC Light (222 nm) against Different Pathogens.

Ultraviolet (UV) light is an effective disinfection technology, able to inactivate a wide range of microorganisms, including bacteria and fungi. A safer UV wavelength of 222 nm, also known as far-UVC, has been proposed to minimize these harmful effects while retaining the light's disinfection capability. This study is aimed at exploring the antimicrobial activity of filtered far-UVC (222 nm) on a panel of pathogens commonly found in nosocomial installations. A panel of Gram-positive and Gram-negative bacteria and yeast pathogens was tested. Microorganisms were deposited on a plastic surface, allowing them to dry before exposure to the far-UVC light at a distance of 50 cm. Results showed that far-UVC light successfully inhibits the growth of the tested pathogens, although at different exposure times. In conclusion, the results of this study provide fundamental information to achieve reliable disinfection performance with far-UVC lamps with potential applications in healthcare facilities like hospitals and long-term care homes.

Biological Activities and Chemical Profiles of Kalanchoe fedtschenkoi Extracts.

In this study, the leaves of Kalanchoe fedtschenkoi were consecutively macerated with hexane, chloroform, and methanol. These extracts were used to assess the bioactivities of the plant. The antimicrobial activity was tested against a panel of Gram-positive and -negative pathogenic bacterial and fungal strains using the microdilution method. The cytotoxicity of K. fedtschenkoi extracts was investigated using human-derived macrophage THP-1 cells through the MTT assay. Finally, the anti-inflammatory activity of extracts was studied using the same cell line by measuring the secretion of IL-10 and IL-6. The phytoconstituents of hexane and chloroform extracts were evaluated using gas chromatography-mass spectrometry (GC/MS). In addition, high-performance liquid chromatography (HPLC) was used to study the phytochemical content of methanol extract. The total flavonoid content (TFC) of methanol extract is also reported. The chemical composition of K. fedtschenkoi extracts was evaluated using Fourier-transform infrared spectroscopy (FTIR). Results revealed that the chloroform extract inhibited the growth of Pseudomonas aeruginosa at 150 µg/mL. At the same concentration, methanol extract inhibited the growth of methicillin-resistant Staphylococcus aureus (MRSA). Regarding their cytotoxicity, the three extracts were highly cytotoxic against the tested cell line at IC50 < 3 µg/mL. In addition, the chloroform extract significantly stimulated the secretion of IL-10 at 50 µg/mL (p < 0.01). GC/MS analyses revealed that hexane and chloroform extracts contain fatty acids, sterols, vitamin E, and triterpenes. The HPLC analysis demonstrated that methanol extract was constituted by quercetin and kaempferol derivatives. This is the first report in which the bioactivities and chemical profiles of K. fedtschenkoi are assessed for non-polar and polar extracts.

Use of a Cellulase from Trichoderma reesei as an Adjuvant for Enterococcus faecalis Biofilm Disruption in Combination with Antibiotics as an Alternative Treatment in Secondary Endodontic Infection.

Apical periodontitis is an inflammation leading to the injury and destruction of periradicular tissues. It is a sequence of events that starts from root canal infection, endodontic treatment, caries, or other dental interventions. Enterococcus faecalis is a ubiquitous oral pathogen that is challenging to eradicate because of biofilm formation during tooth infection. This study evaluated a hydrolase (CEL) from the fungus Trichoderma reesei combined with amoxicillin/clavulanic acid as a treatment against a clinical E. faecalis strain. Electron microscopy was used to visualize the structure modification of the extracellular polymeric substances. Biofilms were developed on human dental apices using standardized bioreactors to evaluate the antibiofilm activity of the treatment. Calcein and ethidium homodimer assays were used to evaluate the cytotoxic activity in human fibroblasts. In contrast, the human-derived monocytic cell line (THP-1) was used to evaluate the immunological response of CEL. In addition, the secretion of the pro-inflammatory cytokines IL-6 and TNF-α and the anti-inflammatory cytokine IL-10 were measured by ELISA. The results demonstrated that CEL did not induce the secretion of IL-6 and TNF-α when compared with lipopolysaccharide used as a positive control. Furthermore, the treatment combining CEL with amoxicillin/clavulanic acid showed excellent antibiofilm activity, with a 91.4% reduction in CFU on apical biofilms and a 97.6% reduction in the microcolonies. The results of this study could be used to develop a treatment to help eradicate persistent E. faecalis in apical periodontitis.

Antimicrobial, Cytotoxic, and Anti-Inflammatory Activities of Tigridia vanhouttei Extracts.

In this work, bulb extracts of Tigridia vanhouttei were obtained by maceration with solvents of increasing polarity. The extracts were evaluated against a panel of pathogenic bacterial and fungal strains using the minimal inhibitory concentration (MIC) assay. The cytotoxicity of the extracts was tested against two cell lines (THP-1 and A549) using the MTT assay. The anti-inflammatory activity of the extracts was evaluated in THP-1 cells by measuring the secretion of pro-inflammatory (IL-6 and TNF-α) and anti-inflammatory (IL-10) cytokines by ELISA. The chemical composition of the extracts was recorded by FTIR spectroscopy, and their chemical profiles were evaluated using GC-MS. The results revealed that only hexane extract inhibited the growth of the clinical isolate of Pseudomonas aeruginosa at 200 µg/mL. Against THP-1 cells, hexane and chloroform extracts were moderately cytotoxic, as they exhibited LC50 values of 90.16, and 46.42 µg/mL, respectively. Treatment with methanol extract was weakly cytotoxic at LC50 443.12 µg/mL against the same cell line. Against the A549 cell line, hexane, chloroform, and methanol extracts were weakly cytotoxic because of their LC50 values: 294.77, 1472.37, and 843.12 µg/mL. The FTIR analysis suggested the presence of natural products were confirmed by carboxylic acids, ketones, hydroxyl groups, or esters. The GC-MS profile of extracts revealed the presence of phytosterols, tetracyclic triterpenes, multiple fatty acids, and sugars. This report confirms the antimicrobial, cytotoxic, and anti-inflammatory activities of T. vanhouttei.

Adherence of SARS-CoV-2 Delta variant to a surgical mask and N95 respirators.

The use of facial protection has been adopted globally due to the COVID-19 pandemic. We dissected four respirators and one surgical mask into layers to determine whether or not the virus adheres to them. These individual layers were contaminated with the SARS-CoV-2 Delta variant, and its release by vortexing was performed. Samples were used to infect Vero cells, and a plaque assay was used to evaluate the adherence of the virus to the layers. Results showed that a cumulative log reduction of the layers reduced the load of the virus by at least sixfold. Our study confirms the effectiveness of facial protection in reducing the transmission and/or infection of SARS-CoV-2.

Mycobacterium avium Subspecies paratuberculosis Infects and Replicates within Human Monocyte-Derived Dendritic Cells.

BACKGROUND: Mycobacterium avium subspecies paratuberculosis (MAP), a member of the mycobacteriaceae family, causes Johne's disease in ruminants, which resembles Crohn's disease (CD) in humans. MAP was proposed to be one of the causes of human CD, but the evidence remains elusive. Macrophages were reported to be the only cell where MAP proliferates in ruminants and humans and is likely the major producer of TNFα-associated inflammation. However, whether human dendritic cells (DCs), another major antigen-presenting cell (APC), have the ability to harbor MAP and disseminate infection, remains unknown. METHODS: Human monocyte-derived dendritic cells (moDCs) were infected with MAP and phagocytosis and intracellular survival were quantified by immunofluorescence (IF) and colony counts, respectively. MoDC cytokine expression was measured via ELISA and their activation state was measured via flow cytometry. RESULTS: We showed that MAP can infect and replicate in human moDCs as means to evade the immune system for successful infection, through inhibition of the phago-lysosome fusion via the secretion of protein tyrosine phosphatase PtpA. This mechanism initially led to a state of tolerance in moDCs and then subsequently caused a pro-inflammatory response as infection persisted, characterized by the upregulation of IL-6 and TNFα, and downregulation of IL-10. Moreover, we showed that moDCs have the ability to phagocytose up to 18% of MAP, when exposed at a multiplicity of infection of 1:1. CONCLUSION: Infection and subsequent proliferation of MAP within moDCs could provide a unique means for the dissemination of MAP to lymphoid tissue, while altering immune responses to facilitate the persistence of infection of host tissues in CD.