RESUMO

AIMS: We investigated the putative fungistatic and fungicidal activities of pomegranate sarcotesta lectin (PgTeL) against Cryptococcus neoformans B3501 (serotype D), specifically the ability of PgTeL to inhibit yeast capsule and biofilm formation in this strain. METHODS AND RESULTS: PgTeL showed a minimum inhibitory concentration of 172.0 µg ml-1, at which it did not exhibit a fungicidal effect. PgTeL concentrations of 4.0-256.0 µg ml-1 reduced biofilm biomass by 31.0%-64.0%. Furthermore, 32.0-256.0 µg ml-1 PgTeL decreased the metabolic activity of the biofilm by 32.0%-93.0%. Scanning electron microscopy images clearly revealed disruption of the biofilm matrix. Moreover, PgTeL disrupted preformed biofilms. At concentrations of 8.0-256.0 µg ml-1, PgTeL reduced metabolic activity in C. neoformans by 36.0%-92.0%. However, PgTeL did not inhibit the ability of B3501 cells to form capsules under stress conditions. CONCLUSIONS: PgTeL inhibited biofilm formation and disrupted preformed biofilms, demonstrating its potential for use as an anticryptococcal agent.

Assuntos

Criptococose , Cryptococcus neoformans , Punica granatum , Lectinas/farmacologia , Punica granatum/metabolismo , Plâncton/metabolismo , Biofilmes , Testes de Sensibilidade Microbiana , Antifúngicos/farmacologia , Antifúngicos/metabolismo

RESUMO

Fusariosis has presented a significant increase in their incidence in the last years. This epidemiological panorama probably is due to the increasing profile of refractory susceptibility of Fusarium spp. to available drugs, especially in immunocompromised individuals. Thus, the development of new compounds with effectiveness on these organisms is a necessity. This study evaluated the antifungal potential of a chloroacetamide derivative (4-BFCA) against resistant Fusarium strains. As a result, the compound was effective against all strains (MIC range 12.5-50 µg/mL). The time kill assay demonstrated that 4-BFCA presents a concentration-dependent fungicidal action. Although its action mechanism has not yet been elucidated, it was possible to observe its efficacy through damages and alterations provoked along the hyphae of Fusarium spp. 4-BFCA maintained a high survival rate of Tenebrio molitor larvae, suggesting that it does not cause acute systemic toxicity on this host at the concentration evaluated. In addition, 4-BFCA was 83.33% effective in combating a fungal infection in vivo on the chorioallantoid membrane of embryonated eggs. Our results are very promising and arouse interest to investigate the action of 4-BFCA on Fusarium strains since it acts as a possible candidate for the development of new therapies for the treatment of fusariosis.

Assuntos

Fusariose , Fusarium , Acetamidas/farmacologia , Acetamidas/uso terapêutico , Antifúngicos/farmacologia , Antifúngicos/uso terapêutico , Fusariose/tratamento farmacológico , Fusariose/epidemiologia , Fusariose/microbiologia , Humanos

RESUMO

We present the structural modification of a commercially available glass ionomer cement by inserting the imidazolium salt 1-n-hexadecyl-3-methylimidazolium chloride (C16MImCl), composing a new biomaterial with antifungal biofilm activity. Test specimens were prepared using a commercial glass ionomer cement to which 10 ppm of cetylpyridinium chloride (reference ionic antifungal agent) or C16MImCl were added. The feasibility and hypoallergenicity of the new biomaterial were assessed by microhardness plastic deformation and chorioallantoic membrane assays. Colony counting and scanning electron microscopy were used to evaluate the modified specimens' antibiofilm activity against three multidrug-resistant Candida species. The modified glass ionomer cement presented a strong antibiofilm activity against Candida spp., without losing its original micromechanical and hypoallergenic properties, rendering it a promising candidate for further application in dentistry.

Assuntos

Antifúngicos , Materiais Biocompatíveis , Cimentos de Ionômeros de Vidro , Imidazóis/química , Antifúngicos/farmacologia , Biofilmes/efeitos dos fármacos , Candida/efeitos dos fármacos , Cimentos de Ionômeros de Vidro/farmacologia , Microscopia Eletrônica de Varredura , Propriedades de Superfície

RESUMO

Introduction. Onychomycosis infections currently show a significant increase, affecting about 10 % of the world population. Trichophyton rubrum is the main agent responsible for about 80 % of the reported infections. The clinical cure for onychomycosis is extremely difficult and effective new antifungal therapy is needed.Hypothesis/Gap Statement. Ex vivo onychomycosis models using porcine hooves can be an excellent alternative for evaluating the efficacy of new anti-dermatophytic agents in a nail lacquer.Aim. Evaluation of the effectiveness of a nail lacquer containing a quinoline derivative on an ex vivo onychomycosis model using porcine hooves, as well as the proposal of a plausible antifungal mechanism of this derivative against dermatophytic strains.Methodology. The action mechanism of a quinoline derivative was evaluated through the sorbitol protection assay, exogenous ergosterol binding, and the determination of the dose-response curves by time-kill assay. Scanning electron microscopy evaluated the effect of the derivative in the fungal cells. The efficacy of a quinoline-derivative nail lacquer on an ex vivo onychomycosis model using porcine hooves was evaluated as well.Results. The quinoline derivative showed a time-dependent fungicidal effect, demonstrating reduction and damage in the morphology of dermatophytic hyphae. In addition, the ex vivo onychomycosis model was effective in the establishment of infection by T. rubrum.Conclusion. Treatment with the quinoline-derivative lacquer showed a significant inhibitory effect on T. rubrum strain in this infection model. Finally, the compound presents high potential for application in a formulation such as nail lacquer as a possible treatment for dermatophytic onychomycosis.

Assuntos

Antifúngicos/farmacologia , Arthrodermataceae/efeitos dos fármacos , Dermatoses do Pé/microbiologia , Casco e Garras/microbiologia , Onicomicose/tratamento farmacológico , Quinolinas/farmacologia , Administração Tópica , Animais , Modelos Animais de Doenças , Dermatoses do Pé/tratamento farmacológico , Humanos , Laca , Onicomicose/microbiologia , Suínos

RESUMO

Fungal infections that affect humans and plants have increased significantly in recent decades. However, these pathogens are still neglected when compared to other infectious agents. Due to the high prevalence of these infections, the need for new molecules with antifungal potential is recognized, as pathogenic species are developing resistance to the main drugs available. This work reports the design and synthesis of 1,2,3-triazole derivatives of 8-hydroxyquinoline, as well as the determination of their activities against a panel of fungal species: Candida spp., Trichosporon asahii, Magnusiomyces capitatus, Microsporum spp., Trichophyton spp. and Fusarium spp. The triazoles 5-(4-phenyl-1H-1,2,3-triazol-1-yl)quinolin-8-ol (12) and 5-(4-(cyclohex-1-en-1-yl)-1H-1,2,3-triazol-1-yl)quinolin-8-ol (16) were more promising, presenting minimum inhibitory concentration (MIC) values between 1-16 µg/ml for yeast and 2-4 µg/ml for dermatophytes. However, no relevant anti-Fusarium spp. activity was observed. In the time-kill assays with Microsporum canis, 12 and 16 presented time-dependent fungicide profile at 96 h and 120 h in all evaluated concentrations, respectively. For Candida guilliermondii, 12 was fungicidal at all concentrations at 6 h and 16 exhibited a predominantly fungistatic profile. Both 12 and 16 presented low leukocyte toxicity at 4 µg/ml and the cell viability was close to 100% after the treatment with 12 at all tested concentrations. The sorbitol assay combined with SEM suggest that damages on the fungal cell wall could be involved in the activity of these derivatives. Given the good results obtained with this series, scaffold 4-(cycloalkenyl or phenyl)-5-triazol-8-hydroxyquinoline appears to be a potential pharmacophore for exploration in the development of new antifungal agents.

Assuntos

Antifúngicos/farmacologia , Fungos/citologia , Fungos/efeitos dos fármacos , Oxiquinolina/química , Oxiquinolina/farmacologia , Triazóis/química , Triazóis/farmacologia , Basidiomycota/efeitos dos fármacos , Candida/efeitos dos fármacos , Sobrevivência Celular , Células Cultivadas , Fusarium/efeitos dos fármacos , Humanos , Leucócitos/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Varredura , Microsporum/efeitos dos fármacos , Oxiquinolina/análogos & derivados , Saccharomycetales/efeitos dos fármacos , Trichophyton/efeitos dos fármacos

RESUMO

In nature, microorganisms often exhibit competitive behavior for nutrients and limited space, allowing them to alter the virulence determinants of pathogens. The human pathogenic yeast Cryptococcus neoformans can be found organized in biofilms, a complex community composed of an extracellular matrix which confers protection against predation. The aim of this study was to evaluate and characterize antagonistic interactions between two cohabiting microorganisms: C. neoformans and the bacteria Serratia marcescens. The interaction of S. marcescens with C. neoformans expressed a negative effect on biofilm formation, polysaccharide capsule, production of urease, and melanization of the yeast. These findings evidence that competition in mixed communities can result in dominance by one species, with direct impact on the physiological modulation of virulence determinants. Such an approach is key for understating the response of communities to the presence of competitors and, ultimately, rationally designing communities to prevent and treat certain diseases.

Assuntos

Biofilmes , Cryptococcus neoformans , Interações Microbianas , Serratia marcescens , Cryptococcus neoformans/patogenicidade , Cryptococcus neoformans/fisiologia , Interações Microbianas/fisiologia , Serratia marcescens/patogenicidade , Serratia marcescens/fisiologia , Fatores de Virulência/metabolismo

RESUMO

Phenotypic heterogeneity is an important trait for the development and survival of many microorganisms including the yeast Cryptococcus spp., a deadly pathogen spread worldwide. Here, we have applied scanning electron microscopy (SEM) to define four Cryptococcus spp. capsule morphotypes, namely Regular, Spiky, Bald, and Phantom. These morphotypes were persistently observed in varying proportions among yeast isolates. To assess the distribution of such morphotypes we implemented an automated pipeline capable of (1) identifying potentially cell-associated objects in the SEM-derived images; (2) computing object-level features; and (3) classifying these objects into their corresponding classes. The machine learning approach used a Random Forest (RF) classifier whose overall accuracy reached 85% on the test dataset, with per-class specificity above 90%, and sensitivity between 66 and 94%. Additionally, the RF model indicates that structural and texture features, e.g., object area, eccentricity, and contrast, are most relevant for classification. The RF results agree with the observed variation in these features, consistently also with visual inspection of SEM images. Finally, our work introduces morphological variants of Cryptococcus spp. capsule. These can be promptly identified and characterized using computational models so that future work may unveil morphological associations with yeast virulence.

Assuntos

Variação Anatômica , Cryptococcus/ultraestrutura , Cápsulas Fúngicas/ultraestrutura , Aprendizado de Máquina , Microscopia Eletrônica de Varredura/métodos , Cryptococcus/genética , Fenótipo

RESUMO

BACKGROUND: Fungal infections are highly prevalent and are responsible for high rates of morbidity and mortality. In this context, the search for new treatment alternatives is very relevant. OBJECTIVES: Analyse chemical compounds for antifungal potential against dermatomycosis fungi. METHODS: The antifungal activity of 121 compounds, intermediates or derivatives of 1,3-bis(aryloxy)propane substituted at C-2 (111 compounds) and isothiouronium derivatives (10 compounds) was investigated through susceptibility tests, mechanism of action, toxicity and hydrogel incorporation. RESULTS: The compound 1,3-bis(3,4-dichlorophenoxy)propan-2-aminium chloride (2j) was the most active fungicide against dermatophytes and Candida spp., at very low concentrations (0.39-3.12 µg/mL), including action on resistant and multidrug-resistant clinical strains. Compound 2j has presented a promising toxicity profile, showing selectivity index >10, relative to human lymphocytes. The compound was classified as non-irritant by the HET-CAM test and did not cause histopathological alterations in pig ear skin, thus presenting an excellent perspective for topical application. 2j targets the fungal cell wall, which was confirmed by scanning electron microscopy, which also indicated the additional ability of 2j to inhibit the Candida albicans pseudohyphae formation and biofilm of Microsporum canis. Compound 2j was incorporated in a hydrogel with bioadhesive potential. The results of the human skin permeation showed that 2j remained significantly in the epidermis, ideally for the dermatomycosis treatment. CONCLUSIONS: Therefore, the compound 2j demonstrated the potential for antifungal drug development, with a action mechanism elucidated and already applied in a semisolid formulation as a new therapeutic option for fungal skin infections.

Assuntos

Antifúngicos/farmacologia , Arthrodermataceae/efeitos dos fármacos , Candida/efeitos dos fármacos , Linfócitos/efeitos dos fármacos , Propano/análogos & derivados , Animais , Antifúngicos/química , Sobrevivência Celular , Células Cultivadas , Galinhas , Membrana Corioalantoide/efeitos dos fármacos , Orelha Externa/efeitos dos fármacos , Epiderme/efeitos dos fármacos , Ergosterol/metabolismo , Feminino , Citometria de Fluxo , Humanos , Hidrogéis , Concentração de Íons de Hidrogênio , Concentração Inibidora 50 , Masculino , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Varredura , Propano/química , Propano/farmacologia , Reologia , Relação Estrutura-Atividade , Suínos

RESUMO

Cryptococcus neoformans is an encapsulated yeast responsible for more than 180,000 deaths per year. The standard therapeutic approach against cryptococcosis is a combination of amphotericin B with flucytosine. In countries where cryptococcosis is most prevalent, 5-fluorocytosine is rarely available, and amphotericin B requires intravenous administration. C. neoformans biofilm formation is related to increased drug resistance, which is an important outcome for hospitalized patients. Here, we describe new molecules with anti-cryptococcal activity. A collection of 66 semisynthetic derivatives of ursolic acid and betulinic acid was tested against mature biofilms of C. neoformans at 25 µM. Out of these, eight derivatives including terpenes, benzazoles, flavonoids, and quinolines were able to cause damage and eradicate mature biofilms. Four terpene compounds demonstrated significative growth inhibition of C. neoformans. Our study identified a pentacyclic triterpenoid derived from betulinic acid (LAFIS13) as a potential drug for anti-cryptococcal treatment. This compound appears to be highly active with low toxicity at minimal inhibitory concentration and capable of biofilm eradication.

Assuntos

Biofilmes/efeitos dos fármacos , Criptococose/prevenção & controle , Cryptococcus neoformans/fisiologia , Triterpenos Pentacíclicos/farmacologia , Linhagem Celular , Criptococose/microbiologia , Cryptococcus neoformans/efeitos dos fármacos , Farmacorresistência Fúngica/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Triterpenos Pentacíclicos/química , Triterpenos/química , Ácido Betulínico , Ácido Ursólico

RESUMO

Development of new antimicrobial agents, capable of combating resistant and multidrug-resistant fungal and bacterial clinical strains, is necessary. This study presents the synthesis and antimicrobial screening of 42 2-substituted-1,4-benzenediols, being 10 novel compounds. In total, 23 compounds showed activity against fungi and/or bacteria. Benzenediol compounds 2, 5, 6, 8, 11, and 12 demonstrated broad spectrum antimicrobial actions, including resistant and multidrug-resistant species of dermatophytes (Trichophyton mentagrophytes), Candida spp. and the ESKAPE panel of bacteria. Minimum inhibitory concentrations of these compounds for fungi and bacterial strains ranged from 25 to 50 µg/ml and 8-128 µg/ml, respectively. The antifungal mechanism of action is related to the fungal cell wall of dermatophytes and membrane disruption to dermatophytes and yeasts, in the presence of compound 8. Specific structural changes, such as widespread thinning along the hyphae and yeast lysis, were observed by scanning electron microscopy. The effects of compound 8 on cell viability are dose-dependent; however they did not cause genotoxicity and mutagenicity in human leukocyte cells nor haemolysis. Moreover, the compounds were identified as nonirritant by the ex-vivo Hen's egg test-chorioallantoic membrane (HET-CAM). The furan-1,4-benzenediol compound 5 showed in vivo efficacy to combat S. aureus infection using embryonated chicken eggs. Therefore, the compounds 8, and 5 are promising as hits for the development of new antimicrobial drugs with reduced toxicity.