Saccharomyces boulardii CNCM I-745 changes lipidemic profile and gut microbiota in a hamster hypercholesterolemic model.

Hypercholesterolemia is a main risk factor of cardiovascular disease. Probiotics are a safe approach to reduce elevated cholesterol without any deleterious effect to human health. Saccharomyces boulardii CNCM I-745 probiotic properties are well documented in a context of intestinal dysbiosis. Recent in vitro and preclinical studies have suggested its potential effects on dyslipidemia. This is the first controlled study investigating the effects of S. boulardii CNCM I-745 on lipidemic profile and gut microbiota in a hamster hypercholesterolemic model. Daily administration (3 g/kg) of S. boulardii for 21 or 39 days in hamsters fed a 0.3% cholesterol-diet significantly reduced total plasma cholesterol (P<0.001) and increased faecal total cholesterol (P<0.05) compared to vehicle-treated animals. S. boulardii significantly modified the gut microbiota composition of the hamster fed a 0.3% cholesterol-diet. These microbial abundancy modifications of the microbiota were correlated to variations of lipidemic values or liver genes expressions. In particularly we found that abundance of g_Allobaculum, the most modified taxon after S. boulardii treatment (+236%; P<0.05), was correlated to variations in plasmatic lipoproteins level and ABCG5 hepatic gene expression. We also observed a not previously described correlation between the levels of g_Oxalobacter in the gut microbiota and total cholesterol plasma concentration. In conclusion, we confirmed the cholesterol-lowering effects of S. boulardii intake and we demonstrated for the first time the S. boulardii effect on gut microbiota in the context of hypercholesterolemia in hamsters. Our results provide new insights for a beneficial and safe approach of hypercholesterolemia treatment and could be considered for clinical development, alone or in addition to conventional treatment.

Diversity of microorganisms in the environment and dry fermented sausages of small traditional French processing units.

Naturally fermented sausages produced in nine traditional French processing units and their environmental surfaces were characterised by microbial and physico-chemical analyses. Salmonella and Staphylococcus aureus were not detected in the environment whereas Listeria monocytogenes was detected in four samples. Staphylococcus/Kocuria, lactic acid bacteria (LAB), Enterobacteriaceae, Pseudomonas, yeasts/moulds and enterococci contaminated the surfaces of two processing units, indicating insufficient cleaning and disinfection procedures. The final sausages did not present any health risk in seven of the processing units. In two of the processing units, the final sausages were contaminated with S. aureus and L. monocytogenes, respectively, at levels exceeding the maximum tolerable limit. Staphylococcus/Kocuria and LAB grew well in the products. Biogenic amines were found in the majority of the final products. Their occurrence was associated with high numbers of lactic acid bacteria and enterococci. The study outlined the processing and microbial diversities of French naturally fermented sausages.

Molecular biology of Streptococcus pneumoniae: an everlasting challenge.

Streptococcus pneumoniae is a model for elucidating: 1) recombination steps of DNA, from its discovery to polarity of integration; 2) long-patch mismatch repair, short-patch repair triggered by A/G and exclusion of deletions; 3) resistance to beta-lactam antibiotics; and 4) factors of virulence. Several of these topics remain a challenge for future investigations.

Molecular characterization of a mutation affecting the amount of Streptococcus pneumoniae penicillin-binding protein 3.

We have studied the molecular structure of the gene for the penicillin binding protein (PBP 3) of the Streptococcus pneumoniae wild-type strain and a laboratory mutant strain that exhibits a reduced amount of this protein on PBP gels. This mutation affects cefotaxime resistance when transferred into resistant strains. We have sequenced the PBP3 gene, dacA, and upstream regions from the wild-type isogenic strain and the laboratory mutant. We show that a deletion of one base-pair in the upstream sequence of this gene account for the phenotype by decreasing the amount of PBP3.

Structural organization of the Streptococcus pneumoniae chromosome and relatedness of penicillin-sensitive and -resistant strains in type 9V.

Fragmentation of Streptococcus pneumoniae genomic DNA with low-frequency-cleavage restriction endonucleases and separation of the fragments by field-inversion gel electrophoresis (FIGE) provides a DNA-fingerprint of a strain. This method enables us to construct a physical and genetic map of the R6 laboratory strain what will be presented. The origin of replication containing several Dna boxes was located in the dnaA region. It was of interest to compare the profiles of subclones. Two clones of strain R36A (R6 and C13) were cultivated separately for more than 15,000 generations in two laboratories. FIGE profiles differed by only one band. Another R36A descendant, isolated in 1958 by Ravin, strain Rx was of interest since it was deficient in Dpn restriction enzymes and methylases and in the hex B function. Its origin was questionable; its profile is identical to others R6 descendants, demonstrating that Rx is derived from R36A. FIGE analysis was carried out on several penicillin-resistant strains of type 9V because penicillin-resistance in this type increased recently. The profiles of a collection of a number of these resistant isolates were very similar, showing that they result from a clone. The profiles of penicillin sensitive isolates of the same type are very similar to the resistant isolates. This suggests that the 9V type has spread recently from a clone, and the resistance genes have mutated and were selected when penicillin was extensively used.