The human-microbiome superorganism and its modulation to restore health.

Microbiome is the community of microorganism that co-live with a host. The human being is the result of the integration of its genome and the coexistence with millions of microorganisms throughout its evolutionary history. Human-microbiome association can be considered a step of integration in evolution, constituting a superorganism. Many emergent diseases are related to the loss of part of this microbiome and its restoration can be achieved by different strategies. Gut microbiome imbalance is particularly associated with numerous inflammatory, immune and nervous system-related diseases by a communication pathway called microbiome-brain axis. Modulation of microbiome by administering prebiotics, like arabinoxylans, and synbiotics is a plausible treatment for dysbiosis, the regulation of neurotransmitters and alleviation of neurological manifestations.

Arabinoxylan from Argentinian whole wheat flour promote the growth of Lactobacillus reuteri and Bifidobacterium breve.

Arabinoxylans are part of dietary fibre and have received attention given their emergent prebiotic character. Four arabinoxylans extracts were obtained from Argentinian soft and hard wheat. In vitro assays were performed to describe the extent to which the extracts from whole wheat flour support selective growth of Bifidobacterium breve and probiotic Lactobacillus reuteri ATCC23272 in a defined media. The prebiotic effect was evaluated by three quantitative scores: relative growth, prebiotic activity score and prebiotic index. For prebiotic index equation the growth of Bacteroides and Clostridium strains was compared to that of bifidobacteria and lactic acid bacteria. All the arabinoxylans extracts supported the growth of Lactobacillus and Bifidobacterium, reaching higher prebiotic activity score values than inulin (0·37 and 0·36 for Lactobacillus and Bifidobacterium respectively). AX2 from soft wheat and AX4 from hard showed similar prebiotic index value to commercial inulin (2·64, 2·52 and 2·22 respectively), and AX3 extract presented higher prebiotic index value (4·09) than the positive control and other prebiotic index reported for arabinoxylans. These extracts could be used as prebiotic, synbiotic compositions or novel food prototypes to treat dysbiosis associated with many diseases. SIGNIFICANCE AND IMPACT OF THE STUDY: The present work demonstrates that AX extracts from Argentinian soft and hard wheat promote efficiently the growth of probiotic strain L. reuteri ATCC23272 and B. breve 286, validated with three different parameters that consider the growth of representative strains of Bacteria genera found in the gut. The evaluation of AX extracts as a food supplement in a murine model could confirm their ability to modulate the microbiome. Novel food prototypes including AX and probiotics could relieve local symptoms and may act as psychobiotics with a beneficial effect on microbiome-brain axis.

Combined effect of synthetic enterocin CRL35 with cell wall, membrane-acting antibiotics and muranolytic enzymes against Listeria cells.

AIMS: To evaluate the inhibition effectiveness of enterocin CRL35 in combination with cell wall, membrane-acting antibiotics and muranolytic enzymes against the foodborne pathogen Listeria. METHODS AND RESULTS: Synthetic enterocin CRL35 alone and in combination with monensin, bacitracin, gramicidin, mutanolysin and lysozyme were used in this study. Minimal inhibitory concentration (MIC) and fractional inhibitory concentration (FIC) index assays were performed using Listeria innocua 7 and Listeria monocytogenes FBUNT as sensitive strains. Antibiotics showed positive interactions with the bacteriocin in both strains tested. On the other hand, when mutanolysin and enterocin CRL35 were added to resting cells in a buffer system, the lytic effect of mutanolysin was enhanced. However, the addition of mutanolysin showed no effect on the growth of L. innocua 7 cells in a culture medium. Moreover, mutanolysin allowed the overgrowth of L. innocua 7 cells to an OD similar to control cells in the presence of inhibitory concentration of enterocin CRL35. In contrast, the combination of lysozyme and enterocin CRL35 resulted in a 50% inhibition of the L. innocua 7 growth. CONCLUSIONS: Based on our results, we conclude that the combination of synthetic enterocin CRL35 with some antibiotics is effective against L. innocua 7 and L. monocytogenes FBUNT cells, and more importantly the amount of these agents to be used was considerably reduced. The effectiveness of the combination of synthetic enterocin CRL35 with muramidases seems to depend on complex environments, and more detailed studies need to be performed to elucidate this issue. SIGNIFICANCE AND IMPACT OF THE STUDY: Enterocin CRL35 represents a promising agent that not only can ensure the quality and safety of food but it can also be combined with several antimicrobial agents important in the medical field.