Publications by authors named "Sergio H Seabra"

Introduction: This study assessed a new antimicrobial paste formulation containing nitrofurantoin for regenerative endodontics against multispecies biofilms.

Methods: Four groups of 11 single-root teeth each were tested: Negative control group (brain-heart infusion broth + micro-organisms); Hoshino 1 conventional tri-antibiotic paste group (1:1:1 ratio); Hoshino 5 group (5:5:5 ratio); Experimental group with nitrofurantoin, ciprofloxacin, and metronidazole. Minimum inhibitory concentrations of each antimicrobial were determined.

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Leishmaniasis encompasses a group of neglected diseases caused by flagellated protozoa belonging to the genus, associated with high morbidity and mortality. The search for compounds with anti- activity that exhibit lower toxicity and can overcome the emergence of resistant strains remains a significant goal. In this context, the calpain inhibitor MDL28170 has previously demonstrated deleterious effects against promastigote forms of , which led us to investigate its role on axenic amastigote forms.

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There is a growing imperative for research into alternative compounds for the treatment of the fungal infections. Thus, many studies have focused on the analysis of antifungal proteins and peptides from different plant sources. Among these molecules are protease inhibitors (PIs).

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The objective of this work was to evaluate the combination of synthetic peptides based on the γ-core motif of defensin PvD1 with amphotericin B (AmB) at different concentrations against Candida albicans. We applied the checkerboard assay using different concentrations of the commercial drug AmB and the synthetic peptides γ31-45PvD1++ and γ33-41PvD1++ against C. albicans, aiming to find combinations with synergistic interactions.

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In the present study, we identified and characterized two defensin-like peptides in an antifungal fraction obtained from Capsicum chinense pepper fruits and inhibited the growth of Colletotrichum scovillei, which causes anthracnose. AMPs were extracted from the pericarp of C. chinense peppers and subjected to ion exchange, molecular exclusion, and reversed-phase in a high-performance liquid chromatography system.

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Malaria is caused by apicomplexan parasites of the genus. is an excellent animal model for the study of human malaria caused by . Merozoites invade erythrocytes but are also found in other host cells including macrophages from the spleen and liver.

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Article Synopsis
  • The study reports the creation and characterization of two new cobalt(II) coordination compounds, investigating their effects on Leishmania amazonensis, a parasite that causes leishmaniasis.
  • Complex (1) showed no toxicity to mammalian cells and had moderate antiproliferative activity against the promastigote form of the parasite, while complex (2) was cytotoxic to mammalian cells but was also effective against the parasite.
  • Mechanistic studies revealed that complex (1) induces mitochondrial dysfunction and apoptosis-like cell death in the parasites, with promising molecular docking results suggesting a potential interaction with crucial proteins, warranting further research.
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The necessity of drug combinations to treat leishmaniasis came to the surface mainly because of the toxicity of current treatments and the emergence of resistant strains. The calpain inhibitor MDL28170 has previously shown anti- activity, therefore its use in association with standard drugs could provide a new alternative for the treatment strategy against leishmaniasis. In this study, we analyzed the potential of the combination of MDL28170 and the antileishmanial drug amphotericin B against and .

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Chagas disease is a neglected tropical disease caused by the protozoan pathogen . The disease is a major public health problem affecting about 6 to 7 million people worldwide, mostly in Latin America. The available therapy for this disease is based on two drugs, nifurtimox and benznidazole, which exhibit severe side effects, including resistance, severe cytotoxicity, variable efficacy and inefficiency in the chronic phase.

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Background: Toxoplasma gondii causes toxoplasmosis and is controlled by activated macrophages. However, infection of macrophages by tachyzoites induces TGF-β signaling (TGF-s) inhibiting nitric oxide (NO) production. NO inhibition may be a general escape mechanism of distinct T.

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Article Synopsis
  • Melatonin shows potential as a treatment for toxoplasmosis by reducing parasite proliferation in infected monkey kidney cells (LLC-MK2), without affecting host cell viability.
  • The study demonstrated that melatonin treatment led to observable changes in parasite morphology and signs of cell death in Toxoplasma gondii.
  • These findings support the idea that melatonin could be developed into new therapies with fewer side effects for treating toxoplasmosis.
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causes several fungal human diseases, mainly chromoblastomycosis, which is extremely difficult to treat. Several studies have shown that human immunodeficiency virus peptidase inhibitors (HIV-PIs) are attractive candidates for antifungal therapies. This work focused on studying the action of HIV-PIs on peptidase activity secreted by and their effects on fungal proliferation and macrophage interaction.

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The emerging opportunistic pathogens comprising the Candida haemulonii complex (C. haemulonii [Ch], C. duobushaemulonii [Cd] and C.

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The current treatments for leishmaniasis bump into several obstacles, including low efficacy, high costs, long monitoring, and several/severe side effects. Consequently, the search for promising compounds is a tangible need. Recently, we reported the anti-Leishmania amazonensis action of asymmetric peptidomimetic compounds containing tartaric acid as core, especially the 157 derivative that contains valine/leucine substituents in its structure.

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Background: Corynebacterium striatum is an emerging multidrug-resistant (MDR) pathogen associated with immunocompromised and chronically ill patients, as well as nosocomial outbreaks. In this study, we characterized 23 MDR C. striatum isolated of bloodstream and catheter-related infections from a hospital of Rio de Janeiro.

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Candida parapsilosis sensu stricto (C. parapsilosis) has emerged as the second/third commonest Candida species isolated from hospitals worldwide. Candida spp.

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We have previously shown that metallocomplexes can control the growth of Toxoplasma gondii, the agent that causes toxoplasmosis. In order to develop new metallodrugs to treat this disease, we investigated the influence of the coordination of sulfadiazine (SDZ), a drug used to treat toxoplasmosis, on the biological activity of the iron(III) complex [Fe(HBPClNOL)Cl]·HO, 1, (HBPClNOL=N-(2-hydroxybenzyl)-N-(2-pyridylmethyl)(3-chloro)(2-hydroxy)-propylamine). The new complex [(Cl)(SDZ)Fe(III)(μ-BPClNOL)Fe(III)(SDZ)(Cl)]·2HO, 2, which was obtained by the reaction between complex 1 and SDZ, was characterized using a range of physico-chemical techniques.

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BACKGROUND Scedosporium/Lomentospora species are opportunistic mould pathogens, presenting notable antifungal resistance. OBJECTIVES/METHODS We analysed the conidia and germinated conidia of S. apiospermum (Sap), S.

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Acanthamoeba castellanii (Ac) are ubiquitously distributed in nature, and by contaminating medical devices such as heart valves and contact lenses, they cause a broad range of clinical presentations to humans. Although several molecules have been described to play a role in Ac pathogenesis, including parasite host-tissue invasion and escaping of host-defense, little information is available on their mechanisms of secretion. Herein, we describe the molecular components secreted by Ac, under different protein availability conditions to simulate host niches.

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Ethanol extracts obtained from Schinus terebinthifolius Raddi fruits and leaves were active against Escherichia coli with MIC of 78 μg mL for both extracts. Phytochemical analyses revealed a major presence of phenolic acids, tannins, fatty acids and acid triterpenes in the leaves and phenolic acids, fatty acids, acid triterpenes and biflavonoids in the fruits. Major compounds isolated from the plant, such as the acid triterpene schinol, the phenolic acid derivative ethyl gallate and the biflavonoids agathisflavone and tetrahydroamentoflavone, showed very little activity against E.

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Background: The association between Staphylococcus haemolyticus and severe nosocomial infections is increasing. However, the extent to which fomites contribute to the dissemination of this pathogen through patients and hospital wards remains unknown.

Objectives: In the present study, sphygmomanometers and thermometers were evaluated as potential fomites of oxacillin-resistant S.

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is a dematiaceous fungus able to cause chromoblastomycosis, phaeohyphomycosis and mycetoma. All these fungal diseases are extremely difficult to treat and often refractory to the current therapeutic approaches. Therefore, there is an urgent necessity to develop new antifungal agents to combat these mycoses.

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A pleiotropic response to the calpain inhibitor MDL28170 was detected in the tomato parasite Phytomonas serpens. Ultrastructural studies revealed that MDL28170 caused mitochondrial swelling, shortening of flagellum and disruption of trans Golgi network. This effect was correlated to the inhibition in processing of cruzipain-like molecules, which presented an increase in expression paralleled by decreased proteolytic activity.

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Candida spp. can adhere to and form biofilms over different surfaces, becoming less susceptible to antifungal treatment. Resistance of biofilms to antifungal agents is multifactorial and the extracellular matrix (ECM) appears to play an important role.

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