RESUMEN
Mangosteen (Garcinia mangostana L.) is a tasty, polyphenol-rich tropical fruit. The edible part is highly appreciated by its aroma, taste and texture. The non-edible part, rich in polyphenols, has been traditionally used in Thai medicine. In this work, flavonoids and phenolic acid/derivatives were identified in mangosteen extracts (ME) from edible and non-edible portions. We first studied the effects of MEs on the growth, metabolism, antioxidant capacity, biofilm formation and antimicrobial capacity of eight bifidobacteria and lactobacilli strains from intestinal origin and two commercial probiotic strains (BB536 and GG). ME concentrations higher than 10-20 % were inhibitory for all strains. However, ME concentrations of 5 % significantly (P < 0.01) increased all strains antioxidant capacity, reduced biofilm-formation, and enhanced inhibition against Gram-positive pathogens. To apply these knowledge, bifunctional fermented milk products were elaborated with 5 % ME and individual strains, which were selected taking into account their growth with ME, and the widest range of values on antioxidant capacity, biofilm formation and antimicrobial activity (bifidobacteria INIA P2 and INIA P467, lactobacilli INIA P459 and INIA P708, and reference strain GG). Most strains survived well manufacture, refrigerated storage and an in vitro simulation of major conditions encountered in the gastrointestinal tract. As expected, products supplemented with ME showed higher polyphenol content and antioxidant capacity levels than control. After sensory evaluation, products containing strains INIA P2, INIA P708 and GG outstood as best.
Asunto(s)
Antioxidantes , Biopelículas , Productos Lácteos Cultivados , Garcinia mangostana , Lactobacillus , Extractos Vegetales , Extractos Vegetales/farmacología , Garcinia mangostana/química , Biopelículas/efectos de los fármacos , Biopelículas/crecimiento & desarrollo , Antioxidantes/farmacología , Lactobacillus/efectos de los fármacos , Lactobacillus/metabolismo , Productos Lácteos Cultivados/microbiología , Bifidobacterium/efectos de los fármacos , Bifidobacterium/crecimiento & desarrollo , Bifidobacterium/metabolismo , Probióticos , Flavonoides/farmacología , Flavonoides/análisis , Humanos , Frutas/química , Frutas/microbiología , Fermentación , Hidroxibenzoatos/farmacología , Microbioma Gastrointestinal/efectos de los fármacos , Polifenoles/farmacologíaRESUMEN
Enterocins are bacteriocins synthesized by Enterococcus strains that show an interesting antimicrobial effectiveness against foodborne pathogens such as Listeria monocytogenes. The objectives of this study were to identify and analyze the expression of enterocin genes of Enterococcus isolated from breast-fed infants and evaluate their ability to inhibit three human isolates of virulent L. monocytogenes, as well as some probiotic bacteria. The susceptibility of the strains of L. monocytogenes to fifteen antibiotics was tested, detecting their resistance to cefoxitin (constitutively resistant), oxacillin, and clindamycin. The production of enterocins A, B, and P was observed in Enterococcus faecium isolates, while enterocin AS-48 was detected in an Enterococcus faecalis isolate. AS-48 showed antilisterial activity by itself, while the joint action of enterocins A and B or B and P was necessary for inhibiting L. monocytogenes, demonstrating the synergistic effect of those combinations. The presence of multiple enterocin genes does not assure the inhibition of L. monocytogenes strains. However, the expression of multiple enterocin genes showed a good correlation with the inhibition capacity of these strains. Furthermore, the potential beneficial strains of lactobacilli and bifidobacteria examined were not inhibited by any of the enterocins produced individually or in combination, with the exception of Bifidobacterium longum BB536, which was inhibited by enterocin AS-48 and the joint production of enterocins A and B or B and P. The enterocins studied here could be candidates for developing alternative treatments against antibiotic-resistant bacterial infections. Moreover, these selected enterocin-producing E. faecium strains isolated from breast-fed infants could be used as probiotic strains due to their antilisterial effect, as well as the absence of virulence factors.
RESUMEN
Soy beverages can be a source of bioactive isoflavones, with potential human health benefits. In this work, the suitability of three Lacticaseibacillus and three Bifidobacterium probiotic strains as functional starters for soy beverage fermentation were evaluated, alongside with the effect of refrigerated storage on the viability of the strains and the isoflavone composition of the fermented beverages. The three bifidobacteria strains suffered a decrease in their viability during refrigeration and only Bifidobacterium breve INIA P734 produced high concentrations of bioactive isoflavones. Meanwhile, L. rhamnosus GG and L. rhamnosus INIA P344 produced high levels of aglycones and, with L. paracasei INIA P272, maintained their viability during the refrigeration period, constituting promising starters to obtain functional soy beverages that could gather the benefits of the bioactive isoflavone aglycones and the probiotic strains. Moreover, the three lactobacilli caused an increase in the antioxidant capacity of the fermented beverages, which was maintained over the refrigerated storage.
RESUMEN
Lacticaseibacillus paracasei INIA P272 and Lacticaseibacillus rhamnosus INIA P344, isolated from breast-fed infants, are two promising bacterial strains for their use in functional foods according to their demonstrated probiotic and technological characteristics. To better understand their probiotic characteristics and evaluate their safety, here we report the draft genome sequences of both strains as well as the analysis of their genetical content. The draft genomes of L. paracasei INIA P272 and L. rhamnosus INIA P344 comprise 3.01 and 3.26 Mb, a total of 2994 and 3166 genes and a GC content of 46.27 % and 46.56 %, respectively. Genomic safety was assessed following the EFSA guidelines: the identification of both strains was confirmed through Average Nucleotide Identity, and the absence of virulence, pathogenic and antibiotic resistance genes was demonstrated. The genome stability analysis revealed the presence of plasmids and phage regions in both genomes, however, CRISPR sequences and other mechanisms to fight against phage infections were encoded. The probiotic abilities of both strains were supported by the presence of genes for the synthesis of SCFA, genes involved in resistance to acid and bile salts or a thiamine production cluster. Moreover, the encoded exopolysaccharide biosynthesis genes could provide additional protection against the deleterious gastrointestinal conditions, besides which, playing a key role in adherence and coaggregation of pathogenic bacteria together with the high number of adhesion proteins and domains encoded by both genomes. Additionally, the bacteriocin cluster genes found in both strains, could provide an advantageous ability to compete against pathogenic bacteria. This genomic study supports the probiotic characteristics described previously for these two strains and satisfies the safety requirements to be used in food products.
Asunto(s)
Lacticaseibacillus rhamnosus , Probióticos , Antibacterianos , Adhesión Bacteriana , Humanos , Lactante , Lacticaseibacillus rhamnosus/genética , Análisis de Secuencia de ADNRESUMEN
Limosilactobacillus reuteri is a beneficial bacterium that inhabits the gastrointestinal tract of different mammals. Diverse beneficial effects have been attributed to specific strains, in part mediated by the production of reuterin. Here, we report the draft genome sequence of L. reuteri INIA P572, a reuterin-producing strain isolated from pig feces.
RESUMEN
Pathogenic ability has been extensively studied in clinical enterococci, but to a lesser extent in community-derived ones. Most studies to date in enterococci from healthy infants have been focused on Enterococcus faecalis, despite the growing concern about nosocomial infections caused by E. faecium. In this work, we studied the antibiotic resistance and virulence determinants of 26 E. faecalis and 15 E. faecium intestinal isolates from Spanish healthy breastfed infants. Overall, commensal enterococci studied contained antibiotic resistance and virulence genes, although their patterns were not according to those described for antibiotic-resistant hospital-associated enterococci. None of the isolates was resistant to vancomycin, although the majority showed resistance to some antibiotics. E. faecalis isolates harbored considerably more virulence determinants than E. faecium isolates, but some genes linked to colonization were abundant in both species. Hemolysin activity was not detected in any of the isolates; and the gelatinase gene, when present, was silent in E. faecium, whereas gelatinase activity occurred in half of the E. faecalis isolates studied. These results suggest an ambivalent role of some virulence determinants as elements of pathogenesis.