Anti-staphylococcal and antifungal substances produced by endospore-forming bacilli.

Some bacteria and fungi are related to deterioration and also transmission of foodborne diseases, emphasizing the need to search new substances that may act in the treatment and prevention of the illnesses transmitted by food. Strains from genus Bacillus produce a variety of substances with inhibitory activity that range from antibiotics to bacteriocins. In this work, three strains, identified as B. pasteurii (Pes1) and B. insolitus (Mam2 and Ame3) presented inhibitory action against staphylococcal strains isolated from food. Out of the 33 strains tested, 31 (94.0%) were inhibited by at least one of three main Bacillus producer strains, being most of them inhibited by strain Pes1, that also was able to inhibit filamentous fungi related to food spoilage. The antimicrobial substances produced by Pes1, Mam2 and Ame3 showed to be resistant to proteolytic enzymes, suggesting these substances have not an active proteinaceous compound, as typical bacteriocins. New studies are being performed to extract and characterize these antimicrobial agents to evaluate their potential application in biological control of microorganisms related to spoilage food and foodborne diseases.

Combined application of origanum vulgare l. essential oil and acetic acid for controlling the growth of staphylococcus aureus in foods / Aplicação combinada do óleo essencial de Origanum vulgare L. e ácido acético para o controle do crescimento de Staphylococcus aureus em alimentos

This study evaluated the occurrence of an enhancing inhibitory effect of the combined application of Origanum vulgare L. essential oil and acetic acid against Staphylococcus aureus by the determination of Fractional Inhibitory Concentration (FIC) index and kill-time assay in nutrient broth, meat broth and in a food model (meat pieces). Acetic acid showed MIC and MFC of 0.6 and 1.25 µL.mL-1, respectively. For O. vulgare essential oil MIC and MBC were 1.25 and 2.5 µL.mL-1, respectively. FIC indexes of the mixture of essential oil and acetic acid at MIC x ½ were £ 1.0, showing an additive effect. No synergy was found at kill-time study. Anti-staphylococcal effect of the antimicrobials alone or in mixture (MIC x ½) was lower in meat than in nutrient and meat broths. The effective combination of essential oils and organic acids could appear as an attractive alternative for the food industry, as the doses to inhibit the microbial growth in foods can be lowered.

Este estudo avaliou a ocorrência de um efeito inibitório potencializado quando da aplicação combinada do óleo essencial de O. vulgare e ácido acético sobre Staphylococcus aureus através da determinação Concentração Inibitória Fracional (FIC) e de ensaios de tempo de morte em caldo nutriente, caldo base carne e em um modelo alimentar (pedaços de carne). O ácido acético mostrou um valor de CIM e CBM de 0,6 e 1,25 µL.mL-1, respectivamente. Estudos prévios encontraram valores de CIM e CBM para o óleo essencial de O. vulgare sobre as cepas teste de S. aureus de 1,25 e 1,5 µL.mL-1, respectivamente. Valores de índices de CIF da mistura do óleo essencial e ácido acético na concentração de CIM x ½ foram £ 1,0 caracterizando uma interação de adição. Nenhum efeito sinérgico foi encontrado nos ensaios de tempo de morte. O efeito anti-estafilocócico dos antimicrobianos isolados ou em combinação (CIM x ½) foi menor quando aplicado em carne em comparação a sua adição em caldo nutriente e caldo carne. A efetiva combinação de óleos essenciais e outros agentes preservativos pode ser reconhecida como uma alternativa promissora para a indústria de alimentos, podendo viabilizando a diminuição de doses de antimicrobianos aplicadas para inibir o crescimento microbiano em alimentos.

In vitro anti-staphylococcal activity of Hyptis martiusii Benth against methicillin-resistant Staphylococcus aureus: MRSA strains / Atividade anti-estafilocócica in vitro de Hyptis martiusii Benth contra linhagens de Staphylococcus aureus resistentes à meticilina: MRSA

This is the first report about the antibacterial activity of Hyptis martiusii Benth. In this study the ethanol extract of H. martiusii was tested for its antimicrobial activity against strains of Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. The growth of all bacterial strains tested was inhibited by the extract. The diameter of inhibition zones varied from 13 to 20 mm for the extract. The MIC and MBC values ranged from 128 to > 1024mg/mL and 256 to > 1024 mg/mL, respectively. It is therefore suggested that extracts from H. martiusii could be used as an anti-Staphylococcus agent. Compared with methicillin and gentamicin, the extract was more effective, being a promising antibacterial agent.

Este é o primeiro relato de atividade antibacteriana de Hyptis martiusii Benth. Neste estudo, o extrato etanólico de H. martiusii foi avaliado para atividade antimicrobiana contra linhagens de Escherichia coli, Pseudomonas aeruginosa e Staphylococcus aureus. O crescimento de todas as bactérias testadas foi inibido pelo extrato. O diâmetro das zonas de inibição variaram de 13 - 20 mm. Os valores da CIM e CBM variaram de 128 a > 1024 mg/mL e 256 a > 1024 mg/mL, respectivamente. Devido a isso, podemos indicar que o extrato etanólico de H. martiusii pode ser usado como um agente anti-Staphylococcus. Quando comparado com outros antibióticos como meticilina e gentamicina, o extrato foi mais efetivo, demonstrando ser um promissor agente antibacteriano.