Antifungal activity of poly(lactic acid) nanofibers containing the essential oil from Corymbia citriodora Hook or the monoterpenes ß-citronellol and citronellal against mycotoxigenic fungi.

Food contamination by mycotoxigenic fungi is one of the principal factors that cause food loss and economic losses in the food industry. The objective of this work was to incorporate the essential oil from Corymbia citriodora Hook and its constituents citronellal and ß-citronellol into poly(lactic acid) nanofibers; to characterize the nanofibers by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy and differential scanning calorimetry; to evaluate the antifungal activity by the fumigation method; to evaluate the antimycotoxigenic activity against Aspergillus carbonarius, Aspergillus ochraceus, Aspergillus westerdijkiae, Aspergillus flavus, and Aspergillus parasiticus; and to evaluate the morphology of these microorganisms. All the nanofibers had a regular, smooth, and continuous morphology. FTIR analyses confirmed that the active ingredients were incorporated into the polymer matrix. All samples exhibited antifungal and ochratoxigenic inhibitory activities of up to 100% and 99%, respectively, with the best results observed for (PLA + 30 wt% ß-citronellol) nanofibers and (PLA + 30 wt% citronellal) nanofibers. However, 100% inhibition of the production of aflatoxin B1 and B2 was not observed. The images obtained by SEM indicated that the nanofibers caused damage to the hyphae, caused a decrease in the production of spores, and caused deformation, rupture, and non-formation of the conid head, might be an alternative for the control of mycotoxigenic fungi.

Invasive candidiasis in a pediatric tertiary hospital: Epidemiology, antifungal susceptibility, and mortality rates.

Invasive infections caused by non-albicans Candida are increasing worldwide. However, there is still a lack of information on invasive candidiasis (IC) in the pediatric setting, including susceptibility profiles and clonal studies. We investigated the clinical, epidemiologic, and laboratory characteristics of IC, possible changes in antifungal susceptibility profiles over time, and the occurrence of clonality in our tertiary children's hospital. We analyzed 123 non-duplicate Candida isolates from sterile sites of pediatric patients in a tertiary hospital in southern Brazil, between 2016 and 2021. Data on demographics, comorbidities, and clinical outcomes were collected. Candida species distribution, antifungal susceptibility profiles, biofilm production, and molecular epidemiology of isolates were assessed using reference methods. The range of IC incidence was 0.88-1.55 cases/1000 hospitalized patients/year, and the IC-related mortality rate was 20.3%. Of the total IC cases, 42.3% were in patients aged < 13 months. Mechanical ventilation, parenteral nutrition, and intensive care unit (ICU) admission were common in this group. In addition, ICU admission was identified as a risk factor for IC-related mortality. The main site of Candida spp. isolation was blood, and non-albicans Candida species were predominant (70.8%). No significant clonal spread was observed among isolates of the three most commonly isolated species, and 99.1% of all isolates were biofilm producers. Non-albicans Candida species were predominant in this study. Notably, clonal expansion and emergence of antifungal drug resistance were not observed in our pediatric setting.

The epidemiology of invasive candidiasis has changed over time and there is still a lack of information in the pediatric setting. Non-albicans Candida species predominated in this study, clonal expansion and emergence of antifungal drug resistance were not observed in our pediatric setting.

Essential oils from Cuminum cyminum and Laurus nobilis and their principal constituents: evaluation of antifungal and antimycotoxigenic potential in Aspergillus species.

The antifungal and antimycotoxigenic activities of the essential oils (EO) from Cuminum cyminum and Laurus nobilis, and their respective principal compounds, cuminaldehyde and 1,8-cineole, were evaluated against fungi of the genus Aspergillus: A. carbonarius, A. niger, A. ochraceus, and A. westerdijkiae. The antifungal activity was determined by the contact method and the mycelial growth of the fungi was evaluated. Scanning electron microscopic (SEM) images were obtained to suggest modes of action of the compounds analysed. The antimycotoxigenic activity was determined by high-performance liquid chromatograph. Aspergillus carbonarius was completely inhibited by cumin EO (500 µl l-1), by laurel EO and by cuminaldehyde (5000 µl l-1). The cumin EO (500 µl l-1) completely inhibited the growth of A. niger. All the samples inhibited the mycelial growth of A. ochraceus, especially cumin EO and cuminaldehyde (250 µl l-1). Aspergillus westerdijkiae was completely inhibited by cumin EO and cuminaldehyde (1000 µl l-1), by laurel EO and 1,8-cineole (10 000 µl l-1). A decrease in the production of ochratoxin A (OTA) was observed post-treatment, except in A. ochraceus, only inhibited by laurel EO. SEM images showed morphological changes in fungal structures and spore inhibition post-treatment. The results confirmed the antifungal and antimycotoxigenic effect of EO and their principal constituents on fungi evaluated.

Antimicrobial and antibiofilm effect of promethazine on bacterial isolates from canine otitis externa: an in vitro study.

Otitis externa is an inflammatory disease of the external ear canal of complex and multifactorial etiology associated with recurrent bacterial infection. This study aimed to assess the antimicrobial and antibiofilm activity of promethazine against bacterial isolates from dogs with otitis externa, as well as the effect of this compound on the dynamics of biofilm formation over 120 h. Planktonic bacterial susceptibility to promethazine was evaluated to determine the minimum inhibitory concentrations (MIC). The minimum biofilm eradication concentration (MBEC) was also determined by broth microdilution. To evaluate the effect on biofilm growth, promethazine was tested at three concentrations MIC, MIC/2 and MIC/8, with daily readings at 48, 72, 96 and 120 h. The MICs of promethazine ranged from 48.83 to 781.25 µg mL-1. Promethazine significantly (P < 0.05) reduced mature biofilm biomass, with MBECs ranging from 48.8 to 6250 µg mL-1 and reduced (P < 0.01) biofilm formation for up to the 120-h, at concentrations corresponding to the MIC obtained against each isolate. Promethazine was effective against microorganisms associated with canine otitis externa. The data suggest that promethazine presents antimicrobial and antibiofilm activity and is a potential alternative to treat and prevent recurrent bacterial otitis in dogs. These results emphasize the importance of drug repurposing in veterinary otology as an alternative to reduce antimicrobial resistance.

Marine Bacillus pumilus substances exhibit antimicrobial effect on multidrug-resistant Staphylococcus aureus.

AIMS: This study aimed to assess the antimicrobial potential of Bp1-AdE, produced by Bacillus pumilus 64-1, and to investigate its mode of action against Staphylococcus aureus and methicillin-resistant S. aureus (MRSA). METHODS AND RESULTS: Bp-1AdE, derived from sponge-associated B. pumilus, exhibited bactericidal activity at 1 550 µg ml-1 against S. aureus ATCC29213 and MRSA strains. Light and fluorescence microscopy revealed drastic cell lysis of S. aureus treated with Bp-1AdE. Scanning and transmission electron microscopy suggested that Bp-1AdE disrupts the cytoplasmic membrane. Toxicity assays showed that Bp-1AdE was non-toxic to Tenebrio molitor larvae. Liquid chromatography-mass spectrometry and Global Natural Product Social spectral libraries identified four substances within Bp-1AdE, including aliphatic alcohols [3,4-dipentylhexane-2,5-diol and 1,1'-(4,5-dibutyl-3,6-dimethylcyclohexane-1,2-diyl)bis(ethan-1-one)] and terpenoids (cholic acid and canrenone). CONCLUSIONS: Bp-1AdE demonstrated selective toxicity and bactericidal activity, highlighting its potential for controlling infections caused by multidrug-resistant S. aureus strains.

Nanocomposites: silver nanoparticles and bacteriocins obtained from lactic acid bacteria against multidrug-resistant Escherichia coli and Staphylococcus aureus.

Drug-resistant bacteria such as Escherichia coli and Staphylococcus aureus represent a global health problem that requires priority attention. Due to the current situation, there is an urgent need to develop new, more effective and safe antimicrobial agents. Biotechnological approaches can provide a possible alternative control through the production of new generation antimicrobial agents, such as silver nanoparticles (AgNPs) and bacteriocins. AgNPs stand out for their antimicrobial potential by employing several mechanisms of action that can act simultaneously on the target cell such as the production of reactive oxygen species and cell wall rupture. On the other hand, bacteriocins are natural peptides synthesized ribosomally that have antimicrobial activity and are produced, among others, by lactic acid bacteria (LAB), whose main mechanism of action is to produce pores at the level of the cell membrane of bacterial cells. However, these agents have disadvantages. Nanoparticles also have limitations such as the tendency to form aggregates, which decreases their antibacterial activity and possible cytotoxic effects, and bacteriocins have a narrow spectrum of action, require high doses to be effective, and can be degraded by proteases. Given these limitations, nanoconjugates of these two agents have been developed that can act synergistically in the control of pathogenic bacteria resistant to antibiotics. This review focuses on knowing relevant aspects of the antibiotic resistance of E. coli and S. aureus, the characteristics of these new generation antibacterial agents, and their effect alone or forming nanoconjugates that are more effective against the multiresistant mentioned bacteria.

Occurrence, genetic diversity, and antimicrobial resistance of methicillin-resistant Staphylococcus spp. in hospitalized and non-hospitalized cats in Brazil.

Methicillin-resistant Staphylococci (MRS) cause infections at various sites and exhibit multidrug resistance. Despite their importance in veterinary medicine, only little is known about Staphylococcus spp. colonizing and infecting cats. Therefore, in this study, we aimed to isolate and identify Staphylococcus spp. colonizing hospitalized and non-hospitalized domestic cats and analyze their antimicrobial resistance profiles, genetic diversity, and risk factors associated with MRS colonization. A total of 218 oral and axillary swabs were obtained from 109 cats, including 77 non-hospitalized and 32 hospitalized cats. After plating on selective media, the isolates were identified via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and rpoB and 16S rRNA gene sequencing. Subsequently, antimicrobial sensitivity of the strains was assessed, and they were screened for mecA gene. Methicillin-resistant S. haemolyticus (MRSH) isolates were subjected to multilocus sequence typing, whereas methicillin-resistant S. pseudintermedius (MRSP) and S. felis isolates were subjected to whole genome sequencing. S. felis was most commonly isolated from non-hospitalized cats (28.1%), whereas S. pseudintermedius and MRS were commonly isolated from hospitalized cats (25%). MRSH isolates from hospitalized animals were classified as ST3. The identified MRSP strains belonged to two well-known sequence types, ST551 and ST71. Moreover, antimicrobial use (p = 0.0001), hospitalization (p = 0.0141), and comorbidities (p = 0.002) were associated with increased MRS prevalence in cats.

Alkaloids solenopsins from fire ants display in vitro and in vivo activity against the yeast Candida auris.

The urgency surrounding Candida auris as a public health threat is highlighted by both the Center for Disease Control (CDC) and World Health Organization (WHO) that categorized this species as a priority fungal pathogen. Given the current limitations of antifungal therapy for C. auris, particularly due to its multiple resistance to the current antifungals, the identification of new drugs is of paramount importance. Some alkaloids abundant in the venom of the red invasive fire ant (Solenopsis invicta), known as solenopsins, have garnered attention as potent inhibitors of bacterial biofilms, and there are no studies demonstrating such effects against fungal pathogens. Thus, we herein investigated the antibiotic efficacy of solenopsin alkaloids against C. auris biofilms and planktonic cells. Both natural and synthetic solenopsins inhibited the growth of C. auris strains from different clades, including fluconazole and amphotericin B-resistant isolates. Such alkaloids also inhibited matrix deposition and altered cellular metabolic activity of C. auris in biofilm conditions. Mechanistically, the alkaloids compromised membrane integrity as measured by propidium iodide uptake in exposed planktonic cells. Additionally, combining the alkaloids with AMB yielded an additive antifungal effect, even against AMB-resistant strains. Finally, both extracted solenopsins and the synthetic analogues demonstrated protective effect in vivo against C. auris infection in the invertebrate model Galleria mellonella. These findings underscore the potent antifungal activities of solenopsins against C. auris and suggest their inclusion in future drug development. Furthermore, exploring derivatives of solenopsins could reveal novel compounds with therapeutic promise.

Auranofin is active against Histoplasma capsulatum and reduces the expression of virulence-related genes.

BACKGROUND: Auranofin is an approved anti-rheumatic drug that has a broad-range inhibitory action against several microorganisms, including human pathogenic fungi. The auranofin activity against Histoplasma capsulatum, the dimorphic fungus that causes histoplasmosis, has not been properly addressed. Since there are few therapeutic options for this life-threatening systemic mycosis, this study evaluated the effects of auranofin on H. capsulatum growth and expression of virulence factors. METHODOLOGY/PRINCIPAL FINDINGS: Minimal inhibitory and fungicidal concentrations (MIC and MFC, respectively) of auranofin against 15 H. capsulatum strains with distinct genetic backgrounds were determined using the yeast form of the fungus and a microdilution protocol. Auranofin activity was also assessed on a macrophage model of infection and on a Tenebrio molitor invertebrate animal model. Expression of virulence-related genes was compared between auranofin treated and untreated H. capsulatum yeast cells using a quantitative PCR assay. Auranofin affected the growth of different strains of H. capsulatum, with MIC and MFC values ranging from 1.25 to 5.0 µM and from 2.5 to >10 µM, respectively. Auranofin was able to kill intracellular H. capsulatum yeast cells and conferred protection against the fungus in the experimental animal model of infection. Moreover, the expression of catalase A, HSP70, superoxide dismutase, thioredoxin reductase, serine proteinase, cytochrome C peroxidase, histone 2B, formamidase, metallopeptidase, Y20 and YPS3 proteins were reduced after six hours of auranofin treatment. CONCLUSIONS/SIGNIFICANCE: Auranofin is fungicidal against H. capsulatum and reduces the expression of several virulence-related genes, which makes this anti-rheumatic drug a good candidate for new medicines against histoplasmosis.

Exploring the Antibacterial and Antiparasitic Activity of Phenylaminonaphthoquinones-Green Synthesis, Biological Evaluation and Computational Study.

Organic compounds with antibacterial and antiparasitic properties are gaining significance for biomedical applications. This study focuses on the solvent-free synthesis (green synthesis) of 1,4-naphthoquinone or 2,3-dichloro-1,4-naphthoquinone with different phenylamines using silica gel as an acid solid support. The study also includes in silico PASS predictions and the discovery of antibacterial and antiparasitic properties of phenylaminonaphthoquinone derivatives 1-12, which can be further applied in drug discovery and development. These activities were discussed in terms of molecular descriptors such as hydrophobicity, molar refractivity, and half-wave potentials. The in vitro antimicrobial potential of the synthesized compounds 1-12 was evaluated against a panel of six bacterial strains (three Gram-positive: Staphylococcus aureus, Proteus mirabilis, and Enterococcus faecalis; and three Gram-negative bacteria: Escherichia coli, Salmonella typhimurium, and Klebsiella pneumoniae). Six compounds (1, 3, 5, 7, 10, and 11) showed better activity toward S. aureus with MIC values between 3.2 and 5.7 µg/mL compared to cefazolin (MIC = 4.2 µg/mL) and cefotaxime (MIC = 8.9 µg/mL), two cephalosporin antibiotics. Regarding in vitro antiplasmodial activity, compounds 1 and 3 were the most active against the Plasmodium falciparum strain 3D7 (chloroquine-sensitive), displaying IC50 values of 0.16 and 0.0049 µg/mL, respectively, compared to chloroquine (0.33 µg/mL). In strain FCR-3 (chloroquine-resistant), most of the compounds showed good activity, with compounds 3 (0.12 µg/mL) and 11 (0.55 µg/mL) being particularly noteworthy. Additionally, docking studies were used to better rationalize the action and prediction of the binding modes of these compounds. Finally, absorption, distribution, metabolism, excretion, and toxicity (ADMET) predictions were performed.

Gram-Negative Bacilli Blood Stream Infection in Patients with Severe Burns: Microbiological and Clinical Evidence from a 9-Year Cohort.

Bloodstream infection is one of the most important and increasing complications in patients with severe burns. Most of the species affecting this population are Gram-negative bacilli that exhibit antimicrobial resistance. We conducted this study to determine the antimicrobial susceptibility profile and resistance mechanisms of these bacterial infections and their clinical associations on morbidity and mortality. We analyzed a retrospective cohort of burn patients. All patients included in this study had monobacterial blood stream infections during their hospital stay. We performed phenotypic and genotypic tests to determine the antimicrobial resistance mechanism and profile of each strain. Univariate and multivariate logistic regression analysis was performed between variables. We found 109 patients with monobacterial bacteremia. Pseudomonas spp. (50.7%), A. baumannii (46.4%), and Klebsiella spp. (13.8%) were the most common causative microorganisms. The Pseudomonas spp. isolates showed resistance to imipenem (81.5%), mainly by class A and class B carbapenemases. The A. baumannii isolates conferred resistance to imipenem (56.2%), mainly by class D carbapenemases. One quarter of Klebsiella spp. showed resistance to 3rd generation cephalosporins. We also observed that a total body surface area greater than 40% and three or more different types of invasive procedures might be related to increased mortality. Multidrug resistance is highly present. The extent of the burned area and a high number of different types of invasive procedures had an impact in decreasing survivorship in burn patients with bacteremia.

Tissue response in a rat model of denture stomatitis treated with tissue conditioner containing antifungal complexed with ß-cyclodextrin.

Introduction. Tissue conditioners modified with antifungals are a potential alternative to denture stomatitis (DS) treatment.Gap Statement. Information on tissue response to this treatment before its clinical application is lacking.Aim. This study aimed to evaluate the tissue response of a tissue conditioner modified with antifungals in a rat model of DS.Methodology. After DS induction for 4 days under antibiotic therapy, Wistar rats had their intraoral devices (IODs) relined with the tissue conditioner Softone without (Soft) or with the MICs against Candida albicans of nystatin (Nys) or chlorhexidine (Chx) complexed or not with ß-cyclodextrin (Nys:ßCD and Chx:ßCD). Three controls were included: healthy rats [negative control (Nc)], rats using a sterile IOD [sterile device (Sd)] and rats with DS that did not receive treatment (DS). After 4 days of treatment, the palatal mucosa under the IODs underwent histological processing for morphohistopathological and histometric analyses, morphology of collagen fibres (birefringence), immunohistochemistry for the expression of cell proliferation (proliferating cell nuclear antigen) and cytokine (IL-1ß).Results. The Nc and Sd groups were similar (P>0.05), displaying epithelial and connective tissues without any discernible changes in the parameters assessed. The DS and Soft groups exhibited pronounced epithelial alterations, cell proliferation and expression of the cytokine IL-1ß. In groups treated with drug incorporation (Nys, Chx, Nys:ßCD and Chx:ßCD), all samples demonstrated a reduction in tissue inflammation or complete tissue recovery, with an epithelium compatible with health. For the immunohistochemical parameters, the Chx, Nys:ßCD and Chx:ßCD groups were comparable with Nc (P>0.05).Conclusion. The proposed treatment could be promising for DS, as it led to the tissue recovery of the palatal mucosa. Nevertheless, much lower concentrations of complexed antifungals were required to achieve a similar or higher degree of tissue response compared with uncomplexed drugs in a modified tissue conditioner formulation.

Essential Oil-Based Soap with Clove and Oregano: A Promising Antifungal and Antibacterial Alternative against Multidrug-Resistant Microorganisms.

The transmission of microorganisms via hands is a critical factor in healthcare-associated infections (HAIs), underscoring the importance of rigorous hand hygiene. The rise of antimicrobial-resistant microorganisms, driven in part by the overuse of antibiotics in clinical medicine, presents a significant global health challenge. Antimicrobial soaps, although commonly used, may exacerbate bacterial resistance and disrupt skin microbiota, posing additional health risks and environmental hazards. Essential oils, with their broad-spectrum antimicrobial properties, offer a promising alternative. This study evaluates the antimicrobial activity of essential oils against various bacterial and fungal strains, including multidrug-resistant isolates. Using a range of in vitro and in vivo antimicrobial assays, including minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), and minimal fungicidal concentration (MFC), the essential oils were tested against a broad spectrum of pathogens. Additionally, the chemical composition of the oils was analyzed in detail using gas chromatography-mass spectrometry (CG-MS). Clove, oregano, and thyme oils demonstrated potent inhibition of all tested ATCC bacterial strains, with MIC values ranging from 3.125 to 50 µL/mL. These oils also showed significant activity against multidrug-resistant Escherichia coli and Pseudomonas aeruginosa strains. Notably, clove oil exhibited remarkable efficacy against fungal strains such as Aspergillus fumigatus and Trichophyton rubrum, with MIC values as low as 1.56 µL/mL. Synergy tests revealed that combinations of clove, oregano, and thyme oils yielded significantly lower MIC values than individual oils, indicating additive or synergistic effects. The formulation of a soap incorporating clove and oregano oils demonstrated efficacy comparable to synthetic antiseptics in vivo. These findings highlight the exceptional antimicrobial potential of essential oils, mainly clove and oregano, against resistant microorganisms, offering a viable alternative to conventional antimicrobial agents.

Synthesis, Physicochemical Characterization, and Antimicrobial Evaluation of Halogen-Substituted Non-Metal Pyridine Schiff Bases.

Four synthetic Schiff bases (PSB1 [(E)-2-(((4-aminopyridin-3-yl)imino)methyl)-4,6-dibromophenol], PSB2 [(E)-2-(((4-aminopyridin-3-yl)imino)methyl)-4,6-diiodophenol], PSB3 [(E)-2-(((4-aminopyridin-3-yl)imino)methyl)-4-iodophenol], and PSB4 [(E)-2-(((4-aminopyridin-3-yl)imino)methyl)-4-chloro-6-iodophenol]) were fully characterized. These compounds exhibit an intramolecular hydrogen bond between the hydroxyl group of the phenolic ring and the nitrogen of the azomethine group, contributing to their stability. Their antimicrobial activity was evaluated against various Gram-negative and Gram-positive bacteria, and it was found that the synthetic pyridine Schiff bases, as well as their precursors, showed no discernible antimicrobial effect on Gram-negative bacteria, including Salmonella Typhi (and mutant derivatives), Salmonella Typhimurium, Escherichia coli, and Morganella morganii. In contrast, a more pronounced biocidal effect against Gram-positive bacteria was found, including Bacillus subtilis, Streptococcus agalactiae, Streptococcus pyogenes, Enterococcus faecalis, Staphylococcus aureus, and Staphylococcus haemolyticus. Among the tested compounds, PSB1 and PSB2 were identified as the most effective against Gram-positive bacteria, with PSB2 showing the most potent biocidal effects. Although the presence of reactive oxygen species (ROS) was noted after treatment with PSB2, the primary mode of action for PSB2 does not appear to involve ROS generation. This conclusion is supported by the observation that antioxidant treatment with vitamin C only partially mitigated bacterial inhibition, indicating an alternative biocidal mechanism.

Integrating whole genome sequencing and machine learning for predicting antimicrobial resistance in critical pathogens: a systematic review of antimicrobial susceptibility tests.

Background: Infections caused by antibiotic-resistant bacteria pose a major challenge to modern healthcare. This systematic review evaluates the efficacy of machine learning (ML) approaches in predicting antimicrobial resistance (AMR) in critical pathogens (CP), considering Whole Genome Sequencing (WGS) and antimicrobial susceptibility testing (AST). Methods: The search covered databases including PubMed/MEDLINE, EMBASE, Web of Science, SCOPUS, and SCIELO, from their inception until June 2024. The review protocol was officially registered on PROSPERO (CRD42024543099). Results: The review included 26 papers, analyzing data from 104,141 microbial samples. Random Forest (RF), XGBoost, and logistic regression (LR) emerged as the top-performing models, with mean Area Under the Receiver Operating Characteristic (AUC) values of 0.89, 0.87, and 0.87, respectively. RF showed superior performance with AUC values ranging from 0.66 to 0.97, while XGBoost and LR showed similar performance with AUC values ranging from 0.83 to 0.91 and 0.76 to 0.96, respectively. Most studies indicate that integrating WGS and AST data into ML models enhances predictive performance, improves antibiotic stewardship, and provides valuable clinical decision support. ML shows significant promise for predicting AMR by integrating WGS and AST data in CP. Standardized guidelines are needed to ensure consistency in future research.

Anti-staphylococcal, antibiofilm and trypanocidal activities of CrataBL encapsulated into liposomes: Lectin with potential against infectious diseases.

The present study aimed to evaluate the anti-staphylococcal, antibiofilm, cytotoxicity and trypanocidal activity, mechanisms of parasite death and immunomodulatory effect of CrataBL encapsulated into liposomes (CrataBL-Lipo). CrataBL-Lipo were prepared by the freeze-thaw technique and characterized. Anti-staphylococcal and antibiofilm activities of CrataBL and CrataBL-Lipo were evaluated against standard and clinical strains of Staphylococcus aureus susceptible and resistant. Thus, broth microdilution method was performed to determine the Minimum Inhibitory Concentration (MIC). Antibiofilm activity at subinhibitory concentrations was evaluated using the crystal violet staining method. Cytotoxicity of CrataBL-Lipo was verified in L929 fibroblasts and J774A.1 macrophages by determining the inhibitory concentration necessary to kill 50 % of cells (IC50). Trypanocidal activities of CrataBL-Lipo was evaluated in Trypanosoma cruzi and the efficacy was expressed as the concentration necessary to kill 50 % of parasites (EC50). The mechanisms of parasite death and immunomodulatory effect of CrataBL-Lipo were evaluated using flow cytometry analysis. CrataBL-Lipo presented Ø of 101.9 ± 1.3 nm (PDI = 0.245), ζ of +33.8 ± 1.3 mV and %EE = 80 ± 0.84 %. CrataBL-Lipo presented anti-staphylococcal activity (MIC = 0.56 mg/mL to 0.72 mg/mL). CrataBL-Lipo inhibited 45.4 %-75.6 % of biofilm formation. No cytotoxicity of CrataBL-Lipo was found (IC50 > 100 mg/L). CrataBL-Lipo presented EC50 of 1.1 mg/L, presenting autophagy, apoptosis and necrosis as death profile. In addition, CrataBL-Lipo reduced the production of IL-10 and TNF-α levels, causing an immunomodulatory effect. CrataBL-Lipo has a therapeutic potential for the treatment of staphylococcal infections and Chagas disease exhibiting a high degree of selectivity for the microorganism, and immunomodulatory properties.

Plant phytochemicals-mediated synthesis of zinc oxide nanoparticles with antimicrobial, pharmacological, and environmental applications.

Nanotechnology is a fast-growing field with large number of applications. Therefore, the current study, was designed to prepare Zinc Oxide nanoparticles (ZnO NPs) from A. modesta leaves extract through a cost-effective method. The prepared NPs were characterized through UV-Vis Spectroscopy (UV-Vis), Dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), scanning electron microscope (SEM), and energy dispersive X-ray (EDX). The XRD and DLS analysis revealed the hexagonal nanocrystalline nature of ZnO NPs. The FTIR results displayed multiple fictional groups and UV results confirmed its optical properties. The average size of the NPs was 68.3 nm with a band gap of 2.71 eV. The SEM images divulge a clover leaf shape of ZnO NPs. The EDX spectrum revealed the presence of zinc and oxygen. The prepared NPs showed excellent biomedical application. The highest antileishmanial activity was 68%, anti-inflammatory activity was 78%, total antioxidant capacity (TAC) was 79.1%, antibacterial potential (ZOI) 22.1 mm, and highest growth inhibition of 85 ± 2.1% against A. rabiei. The adsorption efficiency of 85.3% within 120 min was obtained. Conclusively ZnO NPs have shown potential biomedical and environmental applications and ought to be the more investigated to enhance their practical use.

Bioactive peptides from Tenebrio molitor: physicochemical and antioxidant properties and antimicrobial capacity.

Recent research has demonstrated the increasing interest in using insects for the extraction of bioactive compounds, particularly peptides. These compounds offer a spectrum of beneficial physiological effects. The aim of this study was to standardize a methodology for obtaining bioactive peptides from Tenebrio molitor and evaluate its physicochemical characterization, antioxidant, and antimicrobial potential. Six assays were carried out to hydrolyse larvae protein, with variations in Alcalase concentration (0.04 to 0.08%) and reaction time (3 to 8 h). The results indicated that the process applied to defatted mealworm flour was effective in reducing lipids by 82.5%. Consequently, it was an observed increase of 38.4% in protein content. Additionally, an increase in glycogen content was found in defatted mealworm flour (177 µmol glucose g-1 sample) and peptides (152.81 µmol glucose g-1 sample). The degree of hydrolysis was higher in assays with longer hydrolysis durations (8.14 - 8.38%). The antioxidant capacity was 12 to 14% lower in assays with an incubation time of 8h. In this sense, the methodology proposed in the present study proved to be efficient in obtaining bioactive peptides from T. molitor.

Antimicrobial and antibiofilm activities of Inga cylindrica trypsin inhibitor.

Inga cylindrica, a tropical fruit tree of the Fabaceae family (subfamily Mimosoideae), is native to South America. The seeds from this family are an essential source of trypsin inhibitors, which display promising bioactivity for increasing host defense against pathogens. The aim of the present study was to characterize the antimicrobial and antibiofilm activities of the trypsin inhibitor extracted from I. cylindrica seeds, ICTI. ICTI demonstrated antifungal activity with a minimum inhibitory concentration (MIC) of 32.11 µmol.L-1, and a minimum fungicidal concentration (MFC) of 32.1 µmol.L-1, against Cryptococcus gattii, Candida albicans, Candida glabrata and Candida guilliermondii. Combining ICTI with Amphotericin B had a significant synergistic effect, reducing the concentration of the antibiotic by 75% for C. albicans and 94% for C. gatti. The significant increase (16 x) in activity observed with ergosterol (1.01 mol.L-1) for C. albicans and C. gatti, and the lack of activity against bacterial strains, suggests that ICTI interferes with the integrity of the fungal cell membrane. Treatment with ICTI at 10 x MIC resulted in a 51% reduction in biofilm formation and a 56% decrease in mature biofilm colonies for C. albicans. Finally, ICTI displayed no toxicity in the in vivo Galleria mellonella model. Given its antifungal and antibiofilm properties, ICTI could be a promising candidate for the development of new antimicrobial drug prototypes.

Bioactive potential of Eugenia luschnathiana essential oil and extract: antifungal activity against Candida species isolated from oncological patients.

Immunosuppressed individuals, including those undergoing cancer treatment, are more vulnerable to fungal infections, such as oral candidiasis, impacting their quality of life. Given the limitations of current therapies, the discovery of new antifungal agents, including those of natural origin, is crucial for the proper managing of these infections. We investigated the phytochemical profile and antifungal activity of both the essential oil and crude ethanolic extract (CEE) obtained from Eugenia luschnathiana against reference strains and clinical isolates of Candida from oncology patients. Toxicological characterization was also conducted. Gas chromatography coupled to mass spectrometry (GC-MS) and 1H Nuclear Magnetic Resonance (NMR) were used for phytochemical analysis. Antifungal evaluation was conducted to determine the Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC); evaluation of potential mechanisms of action; activity on a fungal biofilm; evaluation of the cytotoxic effect on human keratinocytes of the HaCat lineage by the MTT method; determination of lethality for Artemia salina larvae. GC-MS identified a predominance of sesquiterpenes in the essential oil, notably (E)-Caryophyllene. The 1H NMR spectrum identified aliphatic, osidic, and aromatic compounds in the crude ethanolic extract. The essential oil showed no antifungal activity. However, the CEE exhibited fungicidal activity, with MIC and MFC ranging from 1.95 µg/mL to 3.90 µg/mL. The antifungal effect was affected by sorbitol, indicating a possible mechanism targeting fungal cell wall structures. At low concentration (19.5 µg/mL), the CEE inhibited 62,78% of C. albicans biofilm. The CEE demonstrated a promising toxicity profile, with an LC50 of 142.4 µg/mL against Artemia salina. In conclusion, the CEE from Eugenia luschnathiana exhibited potent antifungal activity, likely through cell wall disruption, biofilm inhibition, and a favorable toxicity profile for further exploration.