Isolation and Characterization of New Probiotic Strains From Chinese Babies

A Ropy Exopolysaccharide-Producing Strain Bifidobacterium pseudocatenulatum Bi-OTA128 Alleviates Dextran Sulfate Sodium-Induced Colitis in Mice

Inflammatory bowel disease (IBD) is a chronic disease associated with overactive inflammation and gut dysbiosis. Owing to the beneficial effects of bifidobacteria on IBD treatment, this study aimed to investigate the anti-inflammation effects of an exopolysaccharide (EPS)-producing strain Bifidobacterium pseudocatenulatum Bi-OTA128 through a dextran sulfate sodium (DSS)-induced colitis mice model. B. pseudocatenulatum treatment improved DSS-induced colitis symptoms and maintained intestinal barrier integrity by up-regulating MUC2 and tight junctions' expression. The oxidative stress was reduced after B. pseudocatenulatum treatment by increasing the antioxidant enzymes of SOD, CAT, and GSH-Px in colon tissues. Moreover, the overactive inflammatory responses were also inhibited by decreasing the pro-inflammatory cytokines of TNF-α, IL-1β, and IL-6, but increasing the anti-inflammatory cytokine of IL-10. The EPS-producing strain Bi-OTA128 showed better effects than that of a non-EPS-producing stain BLYR01-7 in modulating DSS-induced gut dysbiosis. The Bi-OTA128 treatment increased the relative abundance of beneficial bacteria Bifidobacterium and decreased the maleficent bacteria Escherichia-Shigella, Enterorhabuds, Enterobacter, and Osillibacter associated with intestinal inflammation. Notably, the genera Clostridium sensu stricto were only enriched in Bi-OTA128-treated mice, which could degrade polysaccharides to produce acetic acid and butyrate in the gut. This finding demonstrated a cross-feeding effect induced by the EPS-producing strain in gut microbiota. Collectively, these results highlighted the anti-inflammatory effects of the EPS-producing strain B. pseudocatenulatum Bi-OTA128 on DSS-induced colitis, which could be used as a candidate probiotic supporting recovery from ongoing colitis.

Novel yeasts with potential probiotic characteristics isolated from the endogenous ferment of artisanal Minas cheese

Artisanal Minas cheese (QMA) is traditionally elaborate using raw milk and endogenous ferment (pingo - whey or rala - grated ripened cheese). In the present study, 91 yeast strains were isolated and identified from pingo and rala. Eight yeast species were identified by the MALDI-TOF mass spectrometry and confirmed by sequencing of the ITS region. The yeasts' protease and lipase activities were evaluated in addition to probiotic properties such as tolerance to low pH and bile salts, hydrophobicity, autoaggregation, co-aggregation with pathogens, and antimicrobial susceptibility. The rala ferment showed a greater variety of species. Yarrowia lipolytica was the dominant specie (52.7% of isolates), followed by the Kluyveromyces lactis and Kodamaea ohmeri (9.9 and 6.6%, respectively). From the total yeasts evaluated, 74 strains showed positive enzymatic activity: 52 strains showed lipolytic (51 Y. lipolytica and one Trichosporon japonicum) and 44 proteolytic activities (18 Y. lipolytica, 13 K. ohmeri, 11 K. lactis, and 2 Wickerhamiella sp.). All evaluated isolates demonstrated tolerance to pH 2.0, and 69 isolates supported the presence of bile salts. From them, 12 isolates showed the capacity of autoaggregation (> 30%) and hydrophobicity (> 90.0%) and were then selected for co-aggregation and antibiotic resistance assays. All selected isolates showed co-aggregation with Salmonella Enteritidis, Escherichia coli, and Listeria monocytogenes greater than 30%. None of the yeast showed sensibility to the evaluated antibiotics and antagonistic activity against the evaluated pathogens. The results demonstrated that pingo and rala have different yeast composition with different enzymatic activity, which may affect the characteristics of the cheese. Furthermore, some yeast strains: Y. lipolytica (9 strains isolated from rala) and K. ohmeri (3 strains isolated from pingo) demonstrated attractive probiotic potential.

Bioprospecting for Novel Probiotic Strains from Human Milk and Infants: Molecular, Biochemical, and Ultrastructural Evidence

Simple Summary

Demographic, genetic factors, and maternal lifestyle could modify and alter the microbial diversity of human milk and infants’ gut. We screened human breast milk and infant stool samples from Egyptian sources for possible novel probiotic strains. Forty-one isolates were submitted to the gene bank database, classified, and identified through physiological and biochemical tests. All samples revealed antibiotic resistance, antibacterial activity, and high probiotic features. Six of the isolates revealed less than 95% Average Nucleotide Identity with deposited sequences in the database. Isolate Lactobacillus delbrueckii ASO 100 exhibited the lowest identity ratio with promising probiotic and antibacterial features, enlightening the high probability of being a new probiotic species.

Abstract

Human milk comprises a diverse array of microbial communities with health-promoting effects, including colonization and development of the infant’s gut. In this study, we characterized the bacterial communities in the Egyptian mother–infant pairs during the first year of life under normal breastfeeding conditions. Out of one hundred isolates, forty-one were chosen for their potential probiotic properties. The selected isolates were profiled in terms of morphological and biochemical properties. The taxonomic evidence of these isolates was investigated based on 16S rRNA gene sequence and phylogenetic trees between the isolates’ sequence and the nearest sequences in the database. The taxonomic and biochemical evidence displayed that the isolates were encompassed in three genera: Lactobacillus, Enterococcus, and Lactococcus. The Lactobacillus was the most common genus in human milk and feces samples with a high incidence of its different species (Lacticaseibacillus paracasei, Lactobacillus delbrueckii, Lactiplantibacillus plantarum, Lactobacillus gasseri, and Lacticaseibacillus casei). Interestingly, BlastN and Jalview alignment results evidenced a low identity ratio of six isolates (less than 95%) with database sequences. This divergence was supported by the unique physiological, biochemical, and probiotic features of these isolates. The isolate L. delbrueckii, ASO 100 exhibited the lowest identity ratio with brilliant probiotic and antibacterial features suggesting the high probability of being a new species. Nine isolates were chosen and subjected to probiotic tests and ultrastructural analysis; these isolates exhibited antibiotic resistance and antibacterial activity with high probiotic characteristics, and high potentiality to be used as prophylactic and therapeutic agents in controlling intestinal pathogens.

Complete Genome Sequence and Carbohydrates-Active EnZymes (CAZymes) Analysis of Lactobacillus paracasei DTA72, a Potential Probiotic Strain with Strong Capability to Use Inulin

The whole genome sequence of Lactobacillus paracasei DTA72, isolated from healthy infant feces, is reported, along with the Carbohydrates-Active enZymes (CAZymes) analysis and an in silico safety assessment. Strain DTA72 had previously demonstrated some interesting potential probiotic features, such as a good resistance to gastrointestinal conditions and an anti-Listeria activity. The 3.1 Mb sequenced genome consists of 3116 protein-coding sequences distributed on 340 SEED subsystems. In the present study, we analyzed the fermentation capability of strain DTA72 on six different carbohydrate sources, namely, glucose, fructose, lactose, galactose, xylose, and inulin by using phenotypical and genomic approaches. Interestingly, L. paracasei DTA72 evidenced the best growth performances on inulin with a much shorter lag phase and higher number of cells at the stationary phase in comparison with all the sugars tested. The CAZyme analysis using the predicted amino acid sequences detected 80 enzymes, distributed into the five CAZymes classes. Moreover, the in silico analysis revealed the absence of blood hemolytic genes, transmissible antibiotic resistances, and plasmids in DTA72. The results described in this study, together with those previously reported and particularly the strong capability to utilize inulin as energy source, make DTA72 a very interesting potential probiotic strain to be considered for the production of synbiotic foods. The complete genome data have been deposited in GenBank under the accession number WUJH00000000.