No abstract

In the last years several human commensals have emerged from the gut microbiota studies as potential probiotics or therapeutic agents. Strains of human gut inhabitants such as Akkermansia, Bacteroides, or Faecalibacterium have shown several interesting bioactivities and are thus currently being considered as food supplements or as live biotherapeutics, as is already the case with other human commensals such as bifidobacteria. The large-scale use of these bacteria will pose many challenges and drawbacks mainly because they are quite sensitive to oxygen and/or very difficult to cultivate. This review highlights the properties of some of the most promising human commensals bacteria and summarizes the most up-to-date knowledge on their potential health effects. A comprehensive outlook on the potential strategies currently employed and/or available to produce, stabilize, and deliver these microorganisms is also presented.

The chlorogenic acid and the total polyphenol content were analysed in two different potato varieties (Kennebec, Agria) grown under five different nitrogen fertiliser rates (0, 75, 150, 225, 300 kg ha`). Chlorogenic acid content ranged between 6.022.3 mg kg` fresh weight and was not influenced by fertiliser levels. The chlorogenic acid in potato tubers accounted for almost 90% of the total polyphenols. Free radical scavenging and antioxidant acitivities of the tubers were also analysed. Ethanolic extracts of the tubers showed marked hydrogen-donating activity in the experiment using 1,1-diphenyl-2-picrylhydrazyl (DPPH), they had reducing power as measured by the Fe(III)→Fe(II) reaction, but did not exhibit H O scavenging activity assessed with a chemiluminescence method. Potato extracts showed significant, although weak Cu(II)chelating activity and inhibited the autoxidation of linoleic acid as measured by the thiocyanate method. Chlorogenic acid containing extract of potato, can act as primary and secondary antioxidant in prevention of oxidative stress. The strong correlation between the antioxidant activity and the level of total pholyphenols suggests that the phenolic compounds are important antioxidant components of whole potato tubers. Variety had minimal, while nitrogen fertiliser rate had no effects on the levels of the studied characteristics.

Akkermansia muciniphila is a Gram-negative intestinal anaerobic bacterium recently proposed as a novel probiotic candidate to be incorporated in food and pharmaceutical forms. Despite its multiple health benefits, the data addressing its antimicrobial susceptibility profile remain scarce. However, the absence of acquired resistance in probiotic strains is a compulsory criterion for its approval in the qualified presumption of safety list. This study aimed at characterizing the A. muciniphila DSM 22959 strain’s antimicrobial susceptibility profile using phenotypic and in silico approaches. To establish the phenotypic antimicrobial susceptibility profile of this strain, minimum inhibitory concentrations of eight antimicrobials were determined using broth microdilution and E-test methods. Additionally, the A. muciniphila DSM 22959 genome was screened using available databases and bioinformatics tools to identify putative antimicrobial resistance genes (ARG), virulence factors (VF), genomic islands (GI), and mobile genetic elements (MGE). The same categorization was obtained for both phenotypic methods. Resistance phenotype was observed for gentamicin, kanamycin, streptomycin, and ciprofloxacin, which was supported by the genomic context. No evidence was found of horizontal acquisition or potential transferability of the identified ARG and VF. Thus, this study provides new insights regarding the phenotypic and genotypic antimicrobial susceptibility profiles of the probiotic candidate A. muciniphila DSM 22959.