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Staphylococcus aureus is the etiologic agent of many nosocomial infections, and its biofilm is frequently isolated from medical devices. Moreover, the dissemination of multidrug-resistant (MDR) strains from this pathogen, such as methicillin-resistant S. aureus (MRSA) strains, is a worldwide public health issue. The inhibition of biofilm formation can be used as a strategy to weaken bacterial resistance. Taking that into account, we analysed the ability of marine sponge-associated bacteria to produce antibiofilm molecules, and we found that marine Priestia sp., isolated from marine sponge Scopalina sp. collected on the Brazilian coast, secretes proteins that impair biofilm development from S. aureus. Partially purified proteins (PPP) secreted after 24 hours of bacterial growth promoted a 92% biofilm mass reduction and 4.0 µg/dL was the minimum concentration to significantly inhibit biofilm formation. This reduction was visually confirmed by light microscopy and Scanning Electron Microscopy (SEM). Furthermore, biochemical assays showed that the antibiofilm activity of PPP was reduced by ethylenediaminetetraacetic acid (EDTA) and 1,10 phenanthroline (PHEN), while it was stimulated by zinc ions, suggesting an active metallopeptidase in PPP. This result agrees with mass spectrometry (MS) identification, which indicated the presence of a metallopeptidase from the M28 family. Additionally, whole-genome sequencing analysis of Priestia sp. shows that gene ywad, a metallopeptidase-encoding gene, was present. Therefore, the results presented herein indicate that PPP secreted by the marine Priestia sp. can be explored as a potential antibiofilm agent and help to treat chronic infections.
Assuntos
Antibacterianos , Proteínas de Bactérias , Biofilmes , Staphylococcus aureus , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/fisiologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Antibacterianos/farmacologia , Animais , Testes de Sensibilidade Microbiana , Brasil , Poríferos/microbiologiaRESUMO
This study explores the potential of geranium essential oil as a natural solution for combating marine biofouling, addressing the environmental concerns associated with commercial antifouling coatings. Compounds with bactericidal activities were identified by 13Carbon nuclear magnetic resonance (13C NMR). Thermogravimetric analysis (TGA) revealed minimal impact on film thermal stability, maintaining suitability for antifouling applications. The addition of essential oil induced changes in the morphology of the film and Fourier transform infrared spectroscopy (FTIR) analysis indicated that oil remained within the film. Optical microscopy showed an increase in coating porosity after immersion in a marine environment. A total of 18 bacterial colonies were isolated, with Psychrobacter adeliensis and Shewanella algidipiscicola being the predominant biofilm-forming species. The geranium essential oil-based coating demonstrated the ability to reduce the formation of Psychrobacter adeliensis biofilms and effectively inhibit macrofouling adhesion for a duration of 11 months.
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Incrustação Biológica , Geranium , Óleos Voláteis , Psychrobacter , Biofilmes , Incrustação Biológica/prevenção & controle , Óleos Voláteis/farmacologia , Óleos de Silicone/farmacologia , SiliconesRESUMO
Protozoal infections cause significant morbidity and mortality in humans and animals. The use of several antiprotozoal drugs is associated with serious adverse effects and resistance development, and drugs that are more effective are urgently needed. Microorganisms, mammalian cells and fluids, insects, and reptiles are sources of antimicrobial peptides (AMPs) that act against pathogenic microorganisms; these AMPs have been widely studied as a promising alternative therapeutic option to conventional antibiotics, aiming to treat infections caused by multidrug-resistant pathogens. One advantage of AMP molecules is their adaptability, as they can be easily fine-tuned for broad-spectrum or targeted activity by changing the amino acid residues in their sequence. Consequently, these variations in structural and physicochemical properties can alter the antimicrobial activities of AMPs and decrease resistance development. This article presents an overview of peptide activities against amebiasis, giardiasis, trichomoniasis, Chagas disease, leishmaniasis, malaria, and toxoplasmosis. AMPs and their analogs demonstrate great potential as therapeutics, with potent and selective activity, when compared with commercially available drugs, and hold the potential to act as new scaffolds for the development of novel anti-protozoal drugs.
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Anti-Infecciosos , Animais , Humanos , Anti-Infecciosos/farmacologia , Anti-Infecciosos/uso terapêutico , Peptídeos Catiônicos Antimicrobianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/uso terapêutico , Peptídeos Antimicrobianos , Antibacterianos/uso terapêutico , MamíferosRESUMO
Thermophilic and alkaliphilic microorganisms are unique organisms that possess remarkable survival strategies, enabling them to thrive on a diverse range of substrates. Anoxybacillus, a genus of thermophilic and alkaliphilic bacteria, encompasses 24 species and 2 subspecies. In recent years, extensive research has unveiled the diverse array of thermostable enzymes within this relatively new genus, holding significant potential for industrial and environmental applications. The biomass of Anoxybacillus has demonstrated promising results in bioremediation techniques, while the recently discovered metabolites have exhibited potential in medicinal experiments. This review aims to provide an overview of the key experimental findings related to the biotechnological applications utilizing bacteria from the Anoxybacillus genus.
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Anoxybacillus , Biotecnologia , BiomassaRESUMO
Although Metarhizium anisopliae is one of the most studied fungal biocontrol agents, its infection mechanism is far from being completely understood. Using multidimensional protein identification technology (MudPIT), we evaluated the differential secretome of M. anisopliae E6 induced by the host Rhipicephalus microplus cuticle. The proteomic result showed changes in the expression of 194 proteins after exposure to host cuticle, such as proteins involved in adhesion, penetration, stress and fungal defense. Further, we performed a comparative genomic distribution of differentially expressed proteins of the M. anisopliae secretome against another arthropod pathogen, using the Beauveria bassiana ARSEF2860 protein repertory. Among 47 analyzed protein families, thirty were overexpressed in the M. anisopliae E6 predicted genome compared to B. bassiana. An in vivo toxicity assay using a Galleria mellonella model confirmed that the M. anisopliae E6 secretome was more toxic in cattle tick infections compared to other secretomes, including B. bassiana with cattle ticks and M. anisopliae E6 with the insect Dysdereus peruvianus, which our proteomic results had also suggested. These results help explain molecular aspects associated with host infection specificity due to genetic differences and gene expression control at the protein level in arthropod-pathogenic fungi.
Assuntos
Beauveria , Metarhizium , Rhipicephalus , Animais , Metarhizium/genética , Secretoma , Especificidade de Hospedeiro , Proteômica , Controle Biológico de Vetores/métodos , Rhipicephalus/genética , Rhipicephalus/microbiologiaRESUMO
Abstract Objectives: To evaluate the bacterial microbiome found in tracheostomy cannulas of a group of children diagnosed with glossoptosis secondary to Robin Sequence (RS), and its clinical implications. Methods: Pediatric patients were enrolled in the study at the time of the cannula change in the hospital. During this procedure, the removed cannula was collected and stored for amplicon sequencing of 16s rRNA. DNA extraction was performed using DNeasy PowerBiofilm Kit (QIAGEN® - Cat nº 24000-50) while sequencing was performed with the S5 (Ion S5™ System, Thermo Fisher Scientific), following Brazilian Microbiome Project (BMP) protocol. Results: All 12 patients included in the study were using tracheostomy uncuffed cannulas of the same brand, had tracheostomy performed for over 1-year and had used the removed cannula for approximately 3-months. Most abundant genera found were Aggregatibacter, Pseudomonas, Haemophilus, Neisseria, Staphylococcus, Fusobacterium, Moraxella, Streptococcus, Alloiococcus, and Capnocytophaga. Individual microbiome of each individual was highly variable, not correlating to any particular clinical characteristic. Conclusion: The microbiome of tracheostomy cannulas is highly variable, even among patients with similar clinical characteristics, making it challenging to determine a standard for normality. © 2022 Associa¸c˜ao Brasileira de Otorrinolaringologia e Cirurgia C´ervico-Facial. Published by Elsevier Editora Ltda. This is an open access article under the CC BY license (https://creativecommons.org/licenses/by/4.0/).
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Metabolomics strategies are important tools to get holistic chemical information from a system, but they are scarcely applied to endophytic fungi to understand their chemical profiles of biosynthesized metabolites. Here Penicillium sp. was cultured using One Strain Many Compounds (OSMAC) conditions as a model system to demonstrate how this strategy can help in understanding metabolic profiles and determining bioactive metabolites with the application of metabolomics and statistical analyses, as well as molecular networking. Penicillium sp. was fermented in different culture media and the crude extracts from mycelial biomass (CEm) and broth (CEb) were obtained, evaluated against bacterial strains (Staphylococcus aureus and Pseudomonas aeruginosa), and the metabolomic profiles by LC-DAD-MS were obtained and chemometrics statistical analyses were applied. The CEm and CEb extracts presented different chemical profiles and antibacterial activities; the highest activities observed were against S. aureus from CEm (MIC = 16, 64, and 128 µg/mL). The antibacterial properties from the extracts were impacted for culture media from which the strain was fermented. From the Volcano plot analysis, it was possible to determine statistically the most relevant features for the antibacterial activity, which were also confirmed from biplots of PCA as strong features for the bioactive extracts. These compounds included 75 (13-oxoverruculogen isomer), 78 (austalide P acid), 87 (austalide L or W), 88 (helvamide), 92 (viridicatumtoxin A), 96 (austalide P), 101 (dihydroaustalide K), 106 (austalide k), 110 (spirohexaline), and 112 (pre-viridicatumtoxin). Thus, these features included diketopiperazines, meroterpenoids, and polyketides, such as indole alkaloids, austalides, and viridicatumtoxin A, a rare tetracycline.
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Biofouling is responsible for structural and economic damage to man-made surfaces. Antifouling paints with biocides have been applied to structures to avoid organism adhesion; however, they have high toxicity and are not able to prevent all biofouling processes, necessitating the periodic mechanical removal of organisms and paint reapplication. Thus, there is an urgent demand for novel, effective, and environmentally friendly antifouling alternatives. As isonitrosoacetanilide is the precursor for many compounds with antibacterial activity, we believe that it could have antifouling activity against microfouling and, consequently, against macrofouling. The aim of this work was to investigate the antifouling potential of six isonitrosoacetanilide compounds and their toxicity. The compounds were employed at different concentrations (0.625-1.25-2.5-5-10 µg mL-1) in this study. The biofilm and planktonic bacteria inhibition and biofilm eradication potential were evaluated by crystal violet assay, while Amphibalus amphitrite barnacle settlement was evaluated by cyprid settlement assay. Toxicity evaluation (LC50 and EC50) was performed with A. amphitrite nauplii II and cyprid larvae. At least one of the tested concentrations of 4-Br-INA, 4-CH3-INA, and 2-Br-INA compounds showed nontoxic antifouling activity against microfouling (antibiofilm) and macrofouling (antisettlement). However, only 4-CH3-INA and 2-Br-INA also showed biofilm eradication potential. These compounds with antibiofilm activity and nontoxic effects could be combined with acrylic base paint resin or added directly into commercial paints in place of toxicant biocides to cover artificial structures as friendly antifouling agents.
Assuntos
Incrustação Biológica , Desinfetantes , Thoracica , Humanos , Animais , Incrustação Biológica/prevenção & controle , Biofilmes , Plâncton , Desinfetantes/farmacologiaRESUMO
OBJECTIVES: To evaluate the bacterial microbiome found in tracheostomy cannulas of a group of children diagnosed with glossoptosis secondary to Robin Sequence (RS), and its clinical implications. METHODS: Pediatric patients were enrolled in the study at the time of the cannula change in the hospital. During this procedure, the removed cannula was collected and stored for amplicon sequencing of 16s rRNA. DNA extraction was performed using DNeasy PowerBiofilm Kit (QIAGEN® â Cat nº 24000-50) while sequencing was performed with the S5 (Ion S5™ System, Thermo Fisher Scientific), following Brazilian Microbiome Project (BMP) protocol. RESULTS: All 12 patients included in the study were using tracheostomy uncuffed cannulas of the same brand, had tracheostomy performed for over 1-year and had used the removed cannula for approximately 3-months. Most abundant genera found were Aggregatibacter, Pseudomonas, Haemophilus, Neisseria, Staphylococcus, Fusobacterium, Moraxella, Streptococcus, Alloiococcus, and Capnocytophaga. Individual microbiome of each individual was highly variable, not correlating to any particular clinical characteristic. CONCLUSION: The microbiome of tracheostomy cannulas is highly variable, even among patients with similar clinical characteristics, making it challenging to determine a standard for normality.
Assuntos
Microbiota , Traqueostomia , RNA Ribossômico 16S/genética , Cânula , Microbiota/genética , BrasilRESUMO
Bacterial resistance has become one of the main motives in the worldwide race for undescribed antibacterial agents. The difficulties in the treatment of bacterial infections are a public health issue that increasingly highlights the need for antimicrobial agents. Endophytic microorganisms are a promising alternative in the search for drugs, due to the vast number of metabolites produced with unique characteristics and bioactive potential. This review highlights the importance of endophytic microorganisms as a source of secondary metabolites in the search for active molecules against bacteria of medical importance, with a special focus on gram-negative species. This fact is supported by the findings raised in this review, which brings an arsenal of 166 molecules with characterized chemical structures and their antibacterial activities. In addition, the low cost, ease of maintenance, and optimization-controlled fermentation conditions favor reproducibility in commercial scale. Given their importance, it is necessary to intensify the search for new molecules from endophytic microorganisms, and to increasingly invest in this very promising font.
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Trichomoniasis is the most common non-viral sexually transmitted infection (STI) in the world caused by Trichomonas vaginalis. Failures in the treatment with the 5-nitroimidazole class including parasite resistance to metronidazole elicit new alternatives. Marine natural products are sources of several relevant molecules, presenting a variety of metabolites with numerous biological activities. In this work, we evaluated the anti-T. vaginalis activity of fungi associated with marine invertebrates by mass spectrometry-based metabolomics approaches. After screening of six marine fungi, extract from Penicillium citrinum FMPV 15 has shown to be 100% active against T. vaginalis, and the gel permeation column on Sephadex LH-20® yielded twelve organic fractions which five showed to be active. Metabolomics and statistical analyses were performed with all the samples (extract and fractions), and several compounds were suggested to be related to the activity. These components include citrinin, dicitrinin C, citreoisocoumarin, dihydrocitrinone, decarboxycitrinin, penicitrinone C, and others. The minimum inhibitory concentration (MIC) value of anti-T. vaginalis activity of citrinin was 200 µM. The marine fungi metabolites show potential as new alternatives to overcome drug resistance in T. vaginalis infections.
Assuntos
Produtos Biológicos , Citrinina , Trichomonas vaginalis , Fungos , Espectrometria de Massas , Metronidazol/farmacologia , Extratos VegetaisRESUMO
Trichomoniasis is the most common non-viral sexually transmitted infection worldwide and it may have serious consequences, especially for women. Currently, 5-nitroimidazole drugs are the treatment of choice for trichomoniasis, although presenting adverse effects and reported cases of drug resistance. Metabolites isolated from marine fungi have attracted considerable attention due to their unique chemical structures with diverse biological activities, including antiprotozoal activity. In this study, we showed the anti-Trichomonas vaginalis activity of fractions obtained from marine fungi and the chemical composition of the most active fraction was determined. Ethyl acetate fractions of the fungus Aspergillus niger (EAE03) and Trichoderma harzianum/Hypocrea lixii complex (EAE09) were active against T. vaginalis. These samples, EAE03 and EAE09, were also effective against the fresh clinical isolate metronidazole-resistant TV-LACM2R, presenting MIC values of 2.0 mg/mL and 1.0 mg/mL, respectively. The same MIC values were found against ATCC 30,236 T. vaginalis isolate. In vitro cytotoxicity revealed only the fraction named EAE03 with no cytotoxic effect; however, the active fractions did not promote a significant hemolytic effect after 1-h incubation. Already, the in vivo toxicity evaluation using Galleria mellonella larvae demonstrated that none of the tested samples caused a reduction in animal survival. The fraction EAE03 was followed for purification steps and analyzed by LC-DAD-MS. Eleven compounds were annotated, including butyrolactone, butanolide, and atromentin. Overall, the range of activities reported confirms the potential of marine fungi to produce bioactive molecules.
Assuntos
Antiprotozoários , Tricomoníase , Trichomonas vaginalis , Animais , Antiprotozoários/farmacologia , Antiprotozoários/uso terapêutico , Feminino , Fungos , Humanos , Metronidazol/farmacologia , Tricomoníase/tratamento farmacológicoRESUMO
Cholesterol is a known precursor of arthropod molecules such as the hormone 20-hydroxyecdysone and the antimicrobial boophiline, a component of tick egg wax coat. Because the cholesterol biosynthetic pathway is absent in ticks, it is necessarily obtained from the blood meal, in a still poorly understood process. In contrast, dietary cholesterol absorption is better studied in insects, and many proteins are involved in its metabolism, including Niemann-Pick C (NPC) transporter and acyl-CoA:cholesterol acyltransferase (ACAT), as well as enzymes to convert between free cholesterol and esterified cholesterol. The present work addresses the hypothesis that tick viability can be impaired by interfering with cholesterol metabolism, proposing this route as a target for novel tick control methods. Two drugs, ezetimibe (NPC inhibitor) and avasimibe (ACAT inhibitor) were added to calf blood and used to artificially feed Rhipicephalus microplus females. Results show that, after ingesting avasimibe, tick reproductive ability and egg development are impaired. Also, eggs laid by females fed with avasimibe did not hatch and were susceptible to Pseudomonas aeruginosa adhesion and biofilm formation in their surfaces. The immunoprotective potential of ACAT against ticks was also accessed using two selected ACAT peptides. Antibodies against these peptides were used to artificially feed female ticks, but no deleterious effects were observed. Taken together, data presented here support the hypothesis that enzymes and other proteins involved in cholesterol metabolism are suitable as targets for tick control methods.
Assuntos
Acetamidas , Anticolesterolemiantes , Colesterol na Dieta/metabolismo , Ezetimiba , Rhipicephalus , Sulfonamidas , Controle de Ácaros e Carrapatos , Absorção Fisiológica , Animais , Indutores do Citocromo P-450 CYP3A , Embrião não Mamífero , Feminino , Larva/crescimento & desenvolvimento , Rhipicephalus/crescimento & desenvolvimento , Controle de Ácaros e Carrapatos/métodosRESUMO
Staphylococcus aureus is an opportunistic pathogen involved in several human diseases and presents ability to produce many virulence factors and resistance to antibacterial agents. One of the current strategies to combat such multidrug resistant bacteria is the antibacterial combination therapy. Myricetin is a flavonoid capable of inhibiting several S. aureus virulence factors without influencing on bacterial growth. Therefore, the combination of antibacterials with the antivirulence compound myricetin may provide a positive interaction to control multidrug resistant-bacteria. This work aims to evaluate the effect of the combination of myricetin with oxacillin and vancomycin against methicillin resistant S. aureus (MRSA) and vancomycin intermediate resistant S. aureus (VISA) strains. Concentrations used in combination assays were determined according to the minimum inhibitory concentration (MIC) for antibacterials and to the biofilm minimum inhibitory concentration (BMIC) for myricetin. Checkerboard evaluations showed reduction in MIC for antibacterials in presence of myricetin and time-kill assays confirmed the synergism for these combinations, except for VISA strain when the flavonoid was combined with vancomycin. Importantly, when myricetin was combined with oxacillin, MRSA strain became susceptible to the antibacterial. Myricetin did not reduce staphyloxanthin production, indicating that the oxacillin susceptibility seems not to be related to this step of functional membrane microdomains. In vivo evaluations using Galleria mellonella confirmed the efficacy of oxacillin plus myricetin in treatment of MRSA infected-larvae when compared to the control groups, increasing in 20% host survival. The present work points out the potential of antibacterial and antivirulence compounds combinations as new alternative to control infections by multidrug resistant-bacteria.
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Staphylococcus aureus Resistente à Meticilina , Antibacterianos/farmacologia , Sinergismo Farmacológico , Flavonoides/farmacologia , Humanos , Testes de Sensibilidade Microbiana , Staphylococcus aureusRESUMO
Lycorine is an Amaryllidaceae alkaloid that presents anti-Trichomonas vaginalis activity. T. vaginalis causes trichomoniasis, the most common non-viral sexually transmitted infection. The modulation of T. vaginalis purinergic signaling through the ectonucleotidases, nucleoside triphosphate diphosphohydrolase (NTPDase), and ecto-5'-nucleotidase represents new targets for combating the parasite. With this knowledge, the aim of this study was to investigate whether NTPDase and ecto-5'-nucleotidase inhibition by lycorine could lead to extracellular ATP accumulation. Moreover, the lycorine effect on the reactive oxygen species (ROS) production by neutrophils and parasites was evaluated as well as the alkaloid toxicity. The metabolism of purines was assessed by HPLC. ROS production was measured by flow cytometry. Cytotoxicity against epithelial vaginal cells and fibroblasts was tested, as well as the hemolytic effect of lycorine and its in vivo toxicity in Galleria mellonella larvae. Our findings showed that lycorine caused ATP accumulation due to NTPDase inhibition. The alkaloid did not affect the ROS production by T. vaginalis; however, it increased ROS levels in neutrophils incubated with lycorine-treated trophozoites. Lycorine was cytotoxic against vaginal epithelial cells and fibroblasts; conversely, it was not hemolytic neither exhibited toxicity against the in vivo model of G. mellonella larvae. Overall, besides having anti-T. vaginalis activity, lycorine modulates ectonucleotidases and stimulates neutrophils to secrete ROS. This mechanism of action exerted by the alkaloid could enhance the susceptibility of T. vaginalis to host immune cell, contributing to protozoan clearance.
Assuntos
Alcaloides de Amaryllidaceae/farmacologia , Amaryllidaceae/química , Antiprotozoários/farmacologia , Neutrófilos/metabolismo , Nucleosídeo-Trifosfatase/antagonistas & inibidores , Fenantridinas/farmacologia , Extratos Vegetais/farmacologia , Proteínas de Protozoários/antagonistas & inibidores , Tricomoníase/metabolismo , Trichomonas vaginalis/enzimologia , 5'-Nucleotidase/antagonistas & inibidores , 5'-Nucleotidase/metabolismo , Humanos , Neutrófilos/efeitos dos fármacos , Nucleosídeo-Trifosfatase/metabolismo , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Tricomoníase/parasitologia , Trichomonas vaginalis/efeitos dos fármacos , Trichomonas vaginalis/crescimento & desenvolvimento , Trichomonas vaginalis/metabolismo , Trofozoítos/efeitos dos fármacos , Trofozoítos/enzimologia , Trofozoítos/crescimento & desenvolvimento , Trofozoítos/metabolismoRESUMO
Staphylococcus aureus and Staphylococcus epidermidis are the main agents involved with implant-related infections. Their ability to adhere to medical devices with subsequent biofilm formation is crucial to the development of these infections. Herein, we described the antibacterial and antibiofilm activities of a quinazoline-based compound, N4 -benzyl-N2 -phenylquinazoline-2,4-diamine, against both biofilm-forming pathogens. The minimum inhibitory concentrations (MIC) were determined as 25 µM for S. aureus and 15 µM for S. epidermidis. At sub-MIC concentrations (20 µM for S. aureus and 10 µM for S. epidermidis), the compound was able to inhibit biofilm formation without interfere with bacterial growth, confirmed by scanning electron microscopy. Moreover, surfaces coated with the quinazoline-based compound were able to prevent bacterial adherence. In addition, this compound presented no toxicity to human red blood cells at highest MIC 25 µM and in vivo toxicity assay using Galleria mellonella larvae resulted in 82% survival with a high dose of 500 mg/kg body weight. These features evidence quinazoline-based compound as interesting entities to promising applications in biomedical fields, such as antimicrobial and in anti-infective approaches.
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Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Quinazolinas/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus epidermidis/efeitos dos fármacos , Hemólise/efeitos dos fármacos , Humanos , Testes de Sensibilidade MicrobianaRESUMO
Methicillin-resistant Staphylococcus aureus (MRSA) is a major public health concern representing about 60% of S. aureus isolated from hospitalized patients in countries such as USA and Brazil in the last years. Additionally, the ability to adhere to surfaces and the development of biofilms are important properties of pathogenic bacteria involved in medical device-associated infections, and staphylococci are recognized as the major etiologic agents in these situations. The aim of this study is to evaluate three Brosimum acutifolium flavonoids, 4'-hydroxy-7,8(2â³,2â³-dimethylpyran)flavan (1), brosimine b (2) and 4-hydroxy-lonchocarpin (3), regarding their antibiofilm, antibacterial and antioxidant activities. Flavonoids 1 and 2 were able to reduce S. aureus viability within preformed biofilms in 73% at 50 µM while 2 also reduced biofilm biomass in 48% at 100 µM. Flavonoid 3 was not able to reduce biofilm biomass at assessed concentrations. When tested against methicillin-resistant S. aureus (MRSA) strains, 2 (100 µM) reduced 70%-98% of viable bacteria within 24h-old biofilms. The minimum inhibitory concentration against the methicillin-sensitive Staphylococcus aureus ATCC 25904 was 50 µM for the three compounds. In preliminary assays to evaluate cytotoxicity, 1 was highly hemolytic at concentrations above 50 µM while 2 and 3 did not cause significant hemolysis at 100 µM. The antioxidant activity was observed only in the ethanolic extract and 2. In vivo toxicity evaluations using Galleria mellonella larvae as alternative host model resulted in 83.3% survival for treatment with 1, 76.7% for 2, and 100% for 3 at 500 mg/kg. This study highlights the potential of these flavonoids, especially 2, as antibiofilm agent to control preformed S. aureus biofilms.
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Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Flavonoides/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Animais , Antibacterianos/química , Flavonoides/química , Humanos , Staphylococcus aureus Resistente à Meticilina/fisiologia , Testes de Sensibilidade Microbiana , Mariposas/efeitos dos fármacos , Mariposas/crescimento & desenvolvimento , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimentoRESUMO
Galleria mellonella larvae is an invertebrate that has been extensively used as experimental model in the investigation of microbial virulence and efficacy of antimicrobial agents and can be used to provide faster and cheaper data than traditional test systems. Our objective was to propose the use of G. mellonella larvae as an In Vivo model to evaluate the toxicity of lipid-core nanocapsule (LNC) formulations having different surface coatings. Blank LNC formulations were coated with polysorbate 80 (LNC-1), lecithin and polysorbate 80 (LNC-2), and lecithin, chitosan and polysorbate 80 (LNC-3). Subsequently, the formulations were systemically administered to G. mellonella larvae at doses of 3.75×10-14, 3.75×10-13, 3.75×10-12, 3.75×10-11 and 3.75×10-10 mols of LNC per kg of larvae. The results demonstrated that those nanocapsules having neutral (LNC-1), negative (LNC-2) or positive (LNC-3) surface did not show acute toxicity effects in G. mellonella larvae. G. mellonella larvae is a viable and promising alternative for In Vivo nanotoxicological studies. We conclude that G. mellonella larvae can be used as an alternative model for the screening of the toxicity of polymeric nanocapsules functionalized with (i) polysorbate 80, (ii) lecithin and polysorbate 80, and (iii) lecithin, chitosan and polysorbate 80. Future studies can be now developed in order to evaluate their toxicity when loaded or functionalized with drugs.
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Quitosana , Nanocápsulas , Animais , Quitosana/toxicidade , Composição de Medicamentos , Larva , Lipídeos , Nanocápsulas/toxicidadeRESUMO
Previous studies have shown the effect of surface coatings on biofouling; however, they did not take into account the interaction of the micro and macrofouling communities, the effect of substrate orientation and the zooplankton-zoobenthic coupling together. Therefore, the aim of this study was to evaluate the effect of Zn- and Cu2O-based coatings on micro and macrofouling on steel surfaces, while also observing the role of substrate orientation and zooplankton supply. An experiment was carried out in the Patos Lagoon Estuary in southern Brazil for three months between spring and summer, where ASTM-36 steel plates represented different coatings (Zn- and/or Cu2O-based) and orientations (vertical and horizontal). To assess the zooplankton supply, sampling was carried out weekly using a 200⯵m plankton net. Zn-based coating positively affected microfouling density compared to uncoated surfaces. The same pattern was observed with macrofouling, associated with vagile fauna preference, which represented 70% of the settled macrofoulers. Cu2O-based antifouling painted surfaces showed the highest microfouling density inhibition, while Zn + Cu2O-based coating did not affect the bacteria adhesion but showed lower density compared to Zn-based coating alone. The coatings combination showed the highest invertebrate inhibition. In this way, the macrofouling community was more sensitive than microfouling was to the antifouling coatings tested. The substrate orientation only affected macrofouling, horizontal surfaces being more attractive than vertical. Meroplankton, tychoplankton and holoplankton were recorded on the surfaces, although their representation in plankton was not proportional to the recruits recorded on the substrates. This was probably due to fast dispersion, the interactions of other factors and/or ecological succession stage. Surface coating, substrate orientation, and zooplankton supply interacted with the biofouling process on steel in different ways depending on the organism evaluated. Therefore, copper oxide- and zinc-based coatings were not suitable as coatings to avoid the total biofouling establishment.
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Aderência Bacteriana/efeitos dos fármacos , Incrustação Biológica/prevenção & controle , Aço/análise , Zinco/farmacologia , Bactérias/efeitos dos fármacos , Fenômenos Fisiológicos Bacterianos/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Brasil , Cobre/química , Cobre/farmacologia , Pintura/análise , Zinco/químicaRESUMO
In vivo studies are crucial decision-maker step in order to translate in vitro data to an applied therapy. Considering this we describe a simple method that analyzes and quantifies biofilm formation inside the Galleria mellonella larvae. Toothbrush bristles were employed as an abiotic surface to mimic a medical device. A standardized inoculum of Staphylococcus aureus was systemically injected in the larvae together with the insertion of a bristle in the last proleg pair. After incubation adhered cells were detached from bristles and quantified by colony-forming units (CFU) counting using staphylococci-selective medium. About 3â¯×â¯106â¯CFU of S. aureus were recovered from bristles and scanning electron microscopy (SEM) images confirmed biofilm formation. Control group did not show adherent bacteria, as demonstrated by absence of CFU counting and SEM images, indicating that the insertion procedure is free of bacterial contamination. We present a feasible method to evaluate bacterial biofilm formation in vivo that in the near future can be used to evaluate antibiofilm compounds.