Antimicrobial activity of the Nisin Z producer Lactococcus lactis subsp. lactis Lc08 against Listeria monocytogenes in skim milk / Atividade antimicrobiana de Lactococcus lactis subsp. lactics Lc08 produtor de Nisina Z contra Listeria monocytogenes em leite desnatado

The presented study aimed to verify the effect of different pH values, enzyme solutions and heat treatments on the antimicrobial activity of the bacteriocinogenic strain Lactococcus lactis subsp. lactis Lc08 and to test their antimicrobial activity against Listeria monocytogenes in reconstituted skim milk at refrigeration temperatures. This strain was previously described as a nisin Z producer and capable of inhibiting L. monocytogenes growth in in vitro tests. The antimicrobial activity of the bacteriocin cell-free supernatant of Lc08 was sensitive to enzyme treatments (except papain). The pH values and heating (65ºC for 30min, 75ºC for 15s) had no apparent effect on the antimicrobial activity of the bacteriocin produced by Lc08. Only treatment at autoclave conditions result in loss of their antimicrobial activity. Lc08 presented antimicrobial activity against L. monocytogenes in the milk system after 12h at 25ºC. No effect was found at 7ºC. The results show the application viability of the Lc08 in food systems as a biopreservative against L. monocytogenes.(AU)

O presente estudo teve como objetivo verificar o efeito de diferentes valores de pH, soluções enzimáticas e tratamentos térmicos na atividade antimicrobiana da cepa bacteriocinogênica Lactococcus lactis subsp. lactis Lc08 e testar sua atividade antagonista contra Listeria monocytogenes em leite desnatado reconstituído em diferentes temperaturas de estocagem. Essa cepa já foi descrita como produtora de nisina Z e capaz de inibir o desenvolvimento de L. monocytogenes em testes in vitro. A atividade antimicrobiana do sobrenadante de Lc08 contendo a bacteriocina produzida e livre de células foi sensível ao tratamento pelas enzimas testadas (exceto papaína). A aplicação de diferentes valores de pH e o tratamento térmico (65ºC por 30 min, 75ºC por 15s) não influenciaram na atividade antimicrobiana da bacteriocina produzida por Lc08. Apenas o tratamento em autoclave resultou em perda da sua capacidade em inibir o desenvolvimento de L. monocytogenes. A cepa Lc08 apresentou atividade antagonista contra L. monocytogenes em leite após período de estocagem de 12h a 25ºC. Não foi observado efeito a 7ºC. Os resultados mostram a viabilidade de aplicação da cultura Lc08 ou de sua bacteriocina em produtos lácteos como bioconservador contra L. monocytogenes.(AU)

Identification and biological activity of potential probiotic bacterium isolated from the stomach mucus of breast-fed lamb

The lactic acid bacterium E isolated from the stomach mucus of breast-fed lamb was identified by sequencing of 16S rDNA fragment and species-specific PCR as Lactobacillus reuteri. Its potential antimicrobial activity and ability to modulate immune system in vitro and in vivo was determined. The growth inhibition of potential pathogens decreased from Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella enterica ser. Minnesota to Escherichia coli. The lowest inhibition activity was observed in the case of Candida albicans. The ability of L. reuteri E to modulate biological activities of human and mouse mononuclear cells was estimated in vitro and in vivo, respectively. The production of IL-1 by monocytes in vitro was significantly induced by L. reuteri E (relative activity 2.47). The ability to modulate biological activities of mononuclear cells by living L. reuteri E cells in vitro in comparison to disintegrated L. reuteri E cells in vivo differed. For example lysozyme activity in vitro was inhibited while in vivo was stimulated (relative activities 0.30 and 1.83, respectively). The peroxidase activity in vitro was stimulated while in vivo was inhibited (relative activities 1.53 and 0.17, respectively). Obtained results indicate that L. reuteri E is potential candidate to be used in probiotic preparations for animals and/or human.

Identification and biological activity of potential probiotic bacterium isolated from the stomach mucus of breast-fed lamb

The lactic acid bacterium E isolated from the stomach mucus of breast-fed lamb was identified by sequencing of 16S rDNA fragment and species-specific PCR as Lactobacillus reuteri. Its potential antimicrobial activity and ability to modulate immune system in vitro and in vivo was determined. The growth inhibition of potential pathogens decreased from Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella enterica ser. Minnesota to Escherichia coli. The lowest inhibition activity was observed in the case of Candida albicans. The ability of L. reuteri E to modulate biological activities of human and mouse mononuclear cells was estimated in vitro and in vivo, respectively. The production of IL-1 by monocytes in vitro was significantly induced by L. reuteri E (relative activity 2.47). The ability to modulate biological activities of mononuclear cells by living L. reuteri E cells in vitro in comparison to disintegrated L. reuteri E cells in vivo differed. For example lysozyme activity in vitro was inhibited while in vivo was stimulated (relative activities 0.30 and 1.83, respectively). The peroxidase activity in vitro was stimulated while in vivo was inhibited (relative activities 1.53 and 0.17, respectively). Obtained results indicate that L. reuteri E is potential candidate to be used in probiotic preparations for animals and/or human.

Atividade antimicrobiana de bactérias ácido-lácticas isoladas de queijos de coalho artesanal e industrial frente a microrganismos indicadores / Antimicrobial activity of lactic acid bacteria isolated from artisanal and industrial

Quatro cepas de Lactobacillus spp. e duas cepas de Lactococcus spp. isoladas de queijos de coalho artesanal e industrial foram testadas quanto às suas atividades antimicrobianas. Observou-se atividade antagonista dessas bactérias ácido-lácticas frente a elas, a outras bactérias ácido-lácticas isoladas de queijo de coalho, aos patógenos isolados dos mesmos queijos e a cepas de patógenos de referência. Verificou-se diferença (P<0,05) entre as atividades antagonistas, exceto quando as próprias bactérias ácido-lácticas foram utilizadas como reveladoras. Lactobacillus spp. apresentaram as atividades antagonistas mais potentes.(AU)

Four strains of Lactobacillus spp. and two strains of Lactococcus spp. were isolated from artisanal and industrial "coalho" cheese and tested for inhibitory activity. It was observed antagonistic activity of the lactic acid bacteria against themselves and other lactic acid bacteria and pathogens isolated from the same cheese samples, as well as against pathogenic strains from other sources. Significant difference (P<0.05) was observed among the antagonistic activities, except when lactic acid bacteria were used as indicator. From the tested bacteria, Lactobacillus spp. showed the strongest antagonistic activity.(AU)

The antagonistic activity of the synbiotic containing Lactobacillus acidophilus and pineapple residue FOS against pathogenic bacteria

Abstract Fructooligosaccharide is used widely in many foods and pharmaceutical industries and produced by using different ways such as extracting it from plants or producing it by using plants and microorganisms enzymes. In a previous study, we extracted Fructosyltransferase (Ftase) enzyme from pineapple residue and produced FOS. In this study, we measured the antagonistic activity of two synbiotics, the first synbiotic containing Lactobacillus acidophilus and the produced FOS, the second synbiotic containing Lactobacillus acidophilus and standard FOS, against pathogenic bacteria (P. aeruginosa, E. coli, S. aureus and B cereus). The results showed that the antagonistic activity of both synbiotic types was very close, as there were no significant differences between them except in the antagonistic activity against S. aureus, there was a significant difference between the synbiotic containing the standard FOS, which was the highest in its antagonistic activity compared to the synbiotic containing the produced FOS in this study. The activity of the fructooligosaccharide (FOS) extracted from pineapple residue was evident in enhancing the activity of the probiotic bacteria (L. acidophilus), which had a major role in the production of acids and compounds that inhibited the pathogenic bacteria. The diameters of inhibition areas in the current study ranged between 19.33-28 mm, and E. coli was more susceptible to inhibition, followed by S. aureus, P. aeruginosa, and B. cereus, respectively.

Resumo O fruto-oligossacarídeo (FOS) é amplamente utilizado em muitos alimentos e indústrias farmacêuticas, e é produzido por meio de diferentes maneiras, como extraí-lo de plantas ou produzi-lo usando enzimas de plantas e microrganismos. Em um estudo anterior, extraímos a enzima frutosiltransferase (Ftase) do resíduo de abacaxi e produzimos FOS. Neste estudo, medimos a atividade antagônica de dois simbióticos: o primeiro simbiótico contendo Lactobacillus acidophilus e o FOS produzido, e o segundo simbiótico contendo Lactobacillus acidophilus e o FOS padrão, contra bactérias patogênicas (P. aeruginosa, E. coli, S. aureus e B. cereus). Os resultados mostraram que a atividade antagônica de ambos os tipos simbióticos foi muito próxima, pois não houve diferenças significativas entre eles, exceto na atividade antagônica contra S. aureus, em que houve uma diferença significativa entre o simbiótico contendo o FOS padrão, que foi o mais alto em sua atividade antagônica, em comparação com o simbiótico contendo o FOS produzido neste estudo. A atividade do fruto-oligossacarídeo (FOS) extraído do resíduo de abacaxi ficou evidente no aumento da atividade da bactéria probiótica (L. acidophilus), que teve papel importante na produção de ácidos e compostos inibidores das bactérias patogênicas. Os diâmetros das áreas de inibição no estudo atual variaram entre 19,33 e 28 mm, e E. coli foi mais suscetível à inibição, seguida por S. aureus, P. aeruginosa e B. cereus, respectivamente.

The antagonistic activity of the synbiotic containing Lactobacillus acidophilus and pineapple residue FOS against pathogenic bacteria / A atividade antagônica do simbiótico contendo Lactobacillus acidophilus e resíduo de abacaxi FOS contra bactérias patogênicas

Fructooligosaccharide is used widely in many foods and pharmaceutical industries and produced by using different ways such as extracting it from plants or producing it by using plants and microorganisms' enzymes. In a previous study, we extracted Fructosyltransferase (Ftase) enzyme from pineapple residue and produced FOS. In this study, we measured the antagonistic activity of two synbiotics, the first synbiotic containing Lactobacillus acidophilus and the produced FOS, the second synbiotic containing Lactobacillus acidophilus and standard FOS, against pathogenic bacteria (P. aeruginosa, E. coli, S. aureus and B cereus). The results showed that the antagonistic activity of both synbiotic types was very close, as there were no significant differences between them except in the antagonistic activity against S. aureus, there was a significant difference between the synbiotic containing the standard FOS, which was the highest in its antagonistic activity compared to the synbiotic containing the produced FOS in this study. The activity of the fructooligosaccharide (FOS) extracted from pineapple residue was evident in enhancing the activity of the probiotic bacteria (L. acidophilus), which had a major role in the production of acids and compounds that inhibited the pathogenic bacteria. The diameters of inhibition areas in the current study ranged between 19.33-28 mm, and E. coli was more susceptible to inhibition, followed by S. aureus, P. aeruginosa, and B. cereus, respectively.

O fruto-oligossacarídeo (FOS) é amplamente utilizado em muitos alimentos e indústrias farmacêuticas, e é produzido por meio de diferentes maneiras, como extraí-lo de plantas ou produzi-lo usando enzimas de plantas e microrganismos. Em um estudo anterior, extraímos a enzima frutosiltransferase (Ftase) do resíduo de abacaxi e produzimos FOS. Neste estudo, medimos a atividade antagônica de dois simbióticos: o primeiro simbiótico contendo Lactobacillus acidophilus e o FOS produzido, e o segundo simbiótico contendo Lactobacillus acidophilus e o FOS padrão, contra bactérias patogênicas (P. aeruginosa, E. coli, S. aureus e B. cereus). Os resultados mostraram que a atividade antagônica de ambos os tipos simbióticos foi muito próxima, pois não houve diferenças significativas entre eles, exceto na atividade antagônica contra S. aureus, em que houve uma diferença significativa entre o simbiótico contendo o FOS padrão, que foi o mais alto em sua atividade antagônica, em comparação com o simbiótico contendo o FOS produzido neste estudo. A atividade do fruto-oligossacarídeo (FOS) extraído do resíduo de abacaxi ficou evidente no aumento da atividade da bactéria probiótica (L. acidophilus), que teve papel importante na produção de ácidos e compostos inibidores das bactérias patogênicas. Os diâmetros das áreas de inibição no estudo atual variaram entre 19,33 e 28 mm, e E. coli foi mais suscetível à inibição, seguida por S. aureus, P. aeruginosa e B. cereus, respectivamente.