Antifungal activity of liriodenine on agents of systemic mycoses, with emphasis on the genus Paracoccidioides

Endemic systemic mycoses remain a health challenge, since these opportunistic diseases are increasingly infecting immunosuppressed patients. The simultaneous use of antifungal compounds and other drugs to treat infectious or non-infectious diseases has led to several interactions and undesirable effects. Thus, new antifungal compounds should be investigated. The present study aimed to evaluate the activity of liriodenine extracted from Annona macroprophyllata on agents of systemic mycoses, with emphasis on the genus Paracoccidioides. Methods: The minimum inhibitory concentration (MIC) and minimum fungicide concentration (MFC) were determined by the microdilution method. The cellular alterations caused by liriodenine on a standard P. brasiliensis (Pb18) strain were evaluated by transmission and scanning electron microscopy. Results: Liriodenine was effective only in 3 of the 8 strains of the genus Paracoccidioides and in the Histoplasma capsulatum strain, in a very low concentration (MIC of 1.95 µg.mL-1); on yeasts of Candida spp. (MIC of 125 to 250 µg.mL-1), including C. krusei (250 µg.mL-1), which has intrinsic resistance to fluconazole; and in Cryptococcus neoformans and Cryptococcus gattii (MIC of 62.5 µg.mL-1). However, liriodenine was not effective against Aspergillus fumigatus at the studied concentrations. Liriodenine exhibited fungicidal activity against all standard strains and clinical isolates that showed to be susceptible by in vitro tests. Electron microscopy revealed cytoplasmic alterations and damage to the cell wall of P. brasiliensis (Pb18). Conclusion: Our results indicate that liriodenine is a promising fungicidal compound that should undergo further investigation with some chemical modifications.(AU)

Antifungal activity of liriodenine on agents of systemic mycoses, with emphasis on the genus Paracoccidioides

Endemic systemic mycoses remain a health challenge, since these opportunistic diseases are increasingly infecting immunosuppressed patients. The simultaneous use of antifungal compounds and other drugs to treat infectious or non-infectious diseases has led to several interactions and undesirable effects. Thus, new antifungal compounds should be investigated. The present study aimed to evaluate the activity of liriodenine extracted from Annona macroprophyllata on agents of systemic mycoses, with emphasis on the genus Paracoccidioides. Methods: The minimum inhibitory concentration (MIC) and minimum fungicide concentration (MFC) were determined by the microdilution method. The cellular alterations caused by liriodenine on a standard P. brasiliensis (Pb18) strain were evaluated by transmission and scanning electron microscopy. Results: Liriodenine was effective only in 3 of the 8 strains of the genus Paracoccidioides and in the Histoplasma capsulatum strain, in a very low concentration (MIC of 1.95 µg.mL-1); on yeasts of Candida spp. (MIC of 125 to 250 µg.mL-1), including C. krusei (250 µg.mL-1), which has intrinsic resistance to fluconazole; and in Cryptococcus neoformans and Cryptococcus gattii (MIC of 62.5 µg.mL-1). However, liriodenine was not effective against Aspergillus fumigatus at the studied concentrations. Liriodenine exhibited fungicidal activity against all standard strains and clinical isolates that showed to be susceptible by in vitro tests. Electron microscopy revealed cytoplasmic alterations and damage to the cell wall of P. brasiliensis (Pb18). Conclusion: Our results indicate that liriodenine is a promising fungicidal compound that should undergo further investigation with some chemical modifications.(AU)

Combinação de compostos antimicrobianos e mistura de micro minerais orgânicos e levedura na dieta sobre a qualidade e aceitabilidade da carne bovina

Este estudo foi realizado para avaliar o efeito da combinação de compostos antimicrobianos e uma mistura de microminerais orgânicos e levedura sobre a qualidade e aceitabilidade da carne de bovinos não castrados terminados em confinamento e alimentados com dieta de grãos. O total de 24 bovinos (Bos taurus x Nellore) aos 24 ± 3,2 meses de idade e com peso corporal (PC) de 385,5 ± 3,84 kg foram utilizados em um delineamento inteiramente ao acaso, distribuídos em quatro tratamentos de acordo com o peso inicial, sendo eles: CONT - sem aditivos, MONE - inclusão de 30 mg de monensina/kg de MS, MO+VM - inclusão de 30 mg de monensina/kg de MS + 30 mg de virginiamicina/kg de MS, MO+AD - inclusão de 30 mg de monensina/kg MS + 3,0 g de Advantage Confinamento®/100 kg/PC. O Advantage Confinamento® é composto por microminerais orgânicos e a levedura viva Saccharomyces cerevisiae. Após 84 dias de confinamento, os animais foram abatidos e foi coletado o músculo Longissimus thoracis (LT) para análises de qualidade de carne. A combinação de aditivos (MONE e MO+AD) reduziu o pH e aumentou os valores de L* (P < 0,05). A perda por gotejamento não foi alterada pelas dietas, mas a perda por cozimento foi reduzida (P < 0,05) aos 14 dias no tratamento com MO+AD. A carne de animais alimentados com as dietas MO+VM e MO+AD foi mais macia (P < 0,05). A inclusão de aditivos não alterou (P > 0,05) a oxidação lipídica, que foi afetada apenas pelo tempo de maturação (P < 0,05). Os aditivos não tiveram efeito (P > 0,05) sobre a atividade antioxidante da carne. Não foram observados resíduos de monensina e virginiamicina na carne. Não houve diferenças ( P < 0,05) nos níveis de minerais da carne entre tratamentos. A carne maturada por sete dias foi melhor aceita pelos consumidores e a carne de animais alimentados com a dieta MO+AD resultou em maior disposição de compra. A dieta não alterou (P > 0,05) o odor, o sabor e a aceitabilidade geral da carne. Nos primeiros sete dias de avaliação, a carne dos touros alimentados com a inclusão da dieta MONE ou dieta MO+AD apresentaram os maiores escores de avaliação visual pelo consumidor. A partir dos 7 dias a carne foi considerada indesejável para o consumo humano, para todas as dietas (score abaixo de 5). Em conclusão, a inclusão de composto antimicrobiano e Advantage Confinamento® na dieta de bovinos terminados em confinamento pode melhorar a cor e a textura da carne sem deixar resíduos na carne. Além disso, a suplementação de aditivos, principalmente monensina e Advantage Confinamento®, pode ser benéfica para a aceitação da carne e a intenção de compra pelo consumidor.

This study was carried out to evaluate the effect of the combination of antimicrobial compounds and a blend of organic microminerals and yeast on meat quality and acceptability from bulls finished in feedlot and fed a high-grain diet. A total of 24 bulls (Bos taurus x Nellore) at 24 ± 3.2 months of age and with body weight (BW) of 385.5 ± 3.84 kg were used in a completely randomized design distributed in four treatments according to the initial weight, being them: CONT without additives, MONE inclusion of 30 mg of monensin/kg of DM, MO+VM inclusion of 30 mg of monensin/kg of DM + 30 mg of virginiamycin/kg of DM, MO+AD inclusion of 30 mg monensin/kg DM + 3.0 g Advantage Confinamento®/100 kg/BW. Advantage Confinamento® is composed of organic micro minerals and live yeast Saccharomyces cerevisiae. After 84 days in feedlot, the bulls were slaughtered and Longissimus thoracis (LT) was collected for meat quality analyses. The combination of additives (MONE and MO+AD) reduced pH and increased L* values (P < 0.05). Drip loss was not altered (P > 0.05) by diets, but cooking loss was reduced (P < 0.05) at 14 days of ageing in meat of bulls from MO+AD diet. Meat from bulls fed with MO+VM and MO+AD diets was softer (P < 0.05). The inclusion of additives did not alter (P > 0.05) lipid oxidation, which was affected (P < 0.05) only by ageing time. The additives had no effect (P> 0.05) on meat antioxidant activity. Monensin and virginiamycin residues were not found in meat. There were no differences (P > 0.05) in meat mineral levels among diets. Meat aged for 7 days was better accepted by consumers and meat from bulls fed with MO+AD diet resulted in greater willingness to buy. The diet did not alter (P > 0.05) the odor, flavor and general acceptability of the meat. In the first seven days of evaluation, meat from bulls fed with the inclusion of MONE diet or MO+AD diet presented the highest visual evaluation scores by the consumer. From 7 days onwards, meat was considered undesirable for human consumption, for all diets (score below 5). Furthermore, the inclusion of additives, mainly antimicrobial compounds and Advantage Confinamento®, can be beneficial for meat acceptance and consumer's purchase intention.

Presence of enterotoxigenic Staphylococcus aureus in artisan fruit salads in the city of San Luis, Argentina

An increase in the consumption of fruit juices and minimally processed fruits salads has been observed in recent years all over the world. In this work, the microbiological quality of artisan fruit salads was analysed. Faecal coliforms, Salmonella spp, Shigella spp, Yersinia enterocolitica and Escherichia coli O157:H7 were not detected; nevertheless, eleven strains of Staphylococcus aureus were isolated. By multiplex PCR, all isolates showed positive results for S. aureus 16S rRNA gene and 63.6% of them were positive for sea gene. Furthermore, PCR sea positive strains were able to produce the corresponding enterotoxin. Finally, the inactivation of these strains in fruit salads by nisin, lysozyme and EDTA, was studied. EDTA produced a total S. aureus growth inhibition after 60 h of incubation at a concentration of 250 mg/L. The presence of S. aureus might indicate inadequate hygiene conditions during salad elaboration; however, the enterotoxigenicity of the strains isolated in this study, highlights the risk of consumers' intoxication. EDTA could be used to inhibit the growth of S. aureus in artisan fruit salads and extend the shelf life of these products.

Presence of enterotoxigenic Staphylococcus aureus in artisan fruit salads in the city of San Luis, Argentina

An increase in the consumption of fruit juices and minimally processed fruits salads has been observed in recent years all over the world. In this work, the microbiological quality of artisan fruit salads was analysed. Faecal coliforms, Salmonella spp, Shigella spp, Yersinia enterocolitica and Escherichia coli O157:H7 were not detected; nevertheless, eleven strains of Staphylococcus aureus were isolated. By multiplex PCR, all isolates showed positive results for S. aureus 16S rRNA gene and 63.6% of them were positive for sea gene. Furthermore, PCR sea positive strains were able to produce the corresponding enterotoxin. Finally, the inactivation of these strains in fruit salads by nisin, lysozyme and EDTA, was studied. EDTA produced a total S. aureus growth inhibition after 60 h of incubation at a concentration of 250 mg/L. The presence of S. aureus might indicate inadequate hygiene conditions during salad elaboration; however, the enterotoxigenicity of the strains isolated in this study, highlights the risk of consumers' intoxication. EDTA could be used to inhibit the growth of S. aureus in artisan fruit salads and extend the shelf life of these products.

ATIVIDADE DE EXTRATOS ETANÓLICOS E SUPERCRÍTICOS DE PRÓPOLIS MARROM, VERMELHA E VERDE SOBRE Corynebacterium pseudotuberculosis

A Linfadenite Caseosa (LC) é uma doença infecto-contagiosa debilitante causada pela bactéria Corynebacterium pseudotuberculosis. É caracterizada pelo desenvolvimento de granulomas encapsulados em linfonodos e órgãos, levando a perdas econômicas significativas na caprinovinocultura. O tratamento clínico da LC é geralmente refratário à terapia antibiótica devido ao encapsulamento dos granulomas. A a própolis tem sido objeto de estudos intensivos devido as suas propriedades biológicas e farmacológicas, tal como antibacterianas. Objetivou-se com o presente estudo avaliar a susceptibilidade de C. pseudotuberculosis perante extratos de própolis obtidas pelos métodos de extração supercrítica e etanólica. Foram utilizadas três cepas de C. pseudotuberculosis, a cepa padrão 1002, a cepa patogênica VD57 e a cepa viscerotrópica N1. Para o teste de susceptibilidade a antimicrobianos comerciais utilizou-se as metodologias de disco difusão e microdiluição em caldo. A metodologia da microdiluição em caldo foi utilizada para determinar a Concentração Inibitória Mínima (MIC) e a Concentração Bactericida Mínima (MBC) sobre C. pseudotuberculosis frente aos extratos supercríticos e etanólicos de própolis. Os resultados do teste de sensibilidade utilizando antibióticos comerciais indicaram uma elevada sensibilidade das cepas de C. pseudotuberculosis aos agentes antimicrobianos. O extrato etanólico de própolis verde apresentou a melhor atividade antimicrobiana contra C. pseudotuberculosis, cepa 1002. O extrato supercrítico de própolis vermelha apresentou a melhor atividade antimicrobiana contra C. pseudotuberculosis, cepa VD57. Observamos uma menor atividade antimicrobiana do extrato etanólico de própolis marrom frente as cepas testadas. Conclui-se que o extrato de própolis vermelha supercrítica e verde etanólica apresentaram as melhores atividades antimicrobiana contra as cepas de C. pseudotuberculosis, e podem ser consideradas como opção em futuros estudos sobre o tratamento e prevenção da LC.

Caseous lymphadenitis (CLA) is an infectious-contagious debilitating disease caused by the bacterium Corynebacterium pseudotuberculosis. It is characterized by the development of encapsulated granulomes in lymph nodes and organs, and can cause significant economic losses in the goats and sheep breeding. The clinical treatment of CLA is normally inefficient, since the antibiotics are not able to penetrate the granulome´s capsules. Propolis have been extensively studied due its biological and pharmacological properties, especially the antibiotic potential. The present study had the objective to evaluate the susceptibility of C. pseudotuberculosis strains to ethanolic and supercritical extracts of propolis. Three bacterial strains were used, the standard 1002 strain, the viscerothropic N1 strain and the virulent VD57 strain. For the susceptibility to commercially available antibiotics, the disc diffusion and the broth microdilution methodologies were used. The methodology of broth microdilution was used to determine the Minimum Inhibitory Concentration (MIC) and the Minimum Bactericide Concentration (MBC) of the propolis extracts on the C. pseudotuberculosis strains. The results of the assays using commercial antibiotics showed a high susceptibility for several compounds. The red propolis supercritical extract presented the best activity on the VD57 strain, while the green ethanolic extract had the best action on the 1002 strain. The brow propolis ethanolic extract showed to be the less effective extract. It can be concluded that the red propolis supercritical extract and the green propolis ethanolic extract have the best antimicrobial activity on C. pseudotuberculosis, and can be considered as potential compounds in future in vivo studies on the treatment and prevention of CLA.