Saccharomyces cerevisiae fungemia: Risk factors, outcome and links with S. boulardii-containing probiotic administration.

Saccharomyces cerevisiae fungemia: risk factors, outcome and links with S. boulardii-containing probiotic administration. OBJECTIVE: The aim of our study was to review cases of S. cerevisiae fungemia along with the corresponding risk factors (including S. boulardii probiotic intake), treatment and outcomes. PATIENTS AND METHODS: Retrospective study (2005-2017) of S. cerevisiae fungemia. All the data were extracted from medical files. RESULTS: We identified 10 patients with S. cerevisiae fungemia. Mean age was 59.4 years (range 21-88). Four fifths (80%) were on total parenteral or enteral nutrition, 70% had a central venous line, and 30% were admitted in an Intensive Care Unit (ICU). S. boulardii-containing probiotic prescription was identified in 6 subjects. Three patients with no risk factors such as ICU or central venous catheter were 80 years old or more. Mortality rate was 50%. CONCLUSION: S. cerevisiae fungemia is a rare but life-threatening infection, associated with intake of probiotics containing S. boulardii. Besides classical risk factors, older age should be a contraindication for these probiotics.

Ferulated Pectins and Ferulated Arabinoxylans Mixed Gel for Saccharomyces boulardii Entrapment in Electrosprayed Microbeads.

Ferulated polysaccharides such as pectin and arabinoxylan form covalent gels which are attractive for drug delivery or cell immobilization. Saccharomyces boulardii is a probiotic yeast known for providing humans with health benefits; however, its application is limited by viability loss under environmental stress. In this study, ferulated pectin from sugar beet solid waste (SBWP) and ferulated arabinoxylan from maize bioethanol waste (AX) were used to form a covalent mixed gel, which was in turn used to entrap S. boulardii (2.08 × 108 cells/mL) in microbeads using electrospray. SBWP presented a low degree of esterification (30%), which allowed gelation through Ca2+, making it possible to reduce microbead aggregation and coalescence by curing the particles in a 2% CaCl2 cross-linking solution. SBWP/AX and SBWP/AX+ S. boulardii microbeads presented a diameter of 214 and 344 µm, respectively, and a covalent cross-linking content (dimers di-FA and trimer tri-FA of ferulic acid) of 1.15 mg/g polysaccharide. The 8-5', 8-O-4'and 5-5'di-FA isomers proportions were 79%, 18%, and 3%, respectively. Confocal laser scanning microscopy images of propidium iodide-stained yeasts confirmed cell viability before and after microbeads preparation by electrospray. SBWP/AX capability to entrap S. boulardii would represent an alternative for probiotic immobilization in tailored biomaterials and an opportunity for sustainable waste upcycling to value-added products.

Probiotic Potential, Antioxidant Activity, and Phytase Production of Indigenous Yeasts Isolated from Indigenous Fermented Foods.

While many bacteria have been used as probiotics by industries, only two yeasts, Saccharomyces cerevisiae var. boulardii and Kluyveromyces fragilis (B0399), have been used for this purpose. In the present work, a total of 116 yeasts isolated from Brazilian indigenous fermented food, cocoa fermentation, and kefir were in vitro characterized for probiotic attributes. From 116 isolates, 36 were tolerant to gastrointestinal conditions evaluated by tolerance to pH 2.0, bile salts (0.3% w/v), and 37 °C temperature. From those, 15 isolates showed a similar or higher percentage (P < 0.05) of hydrophobicity, autoaggregation, and coaggregation with E. coli than the reference strain S. boulardii. All these strains showed a high percentage of adhesion to Caco-2 cells (> 63%) and antioxidant activity (ranging from 18 to 62%). Phytate hydrolysis was evaluated for these yeasts and 13 strains showed positive results, which is important for nutrient availability in plant-based foods. These results are important insights for characterization of novel probiotic yeast strains as well as to aggregate functional value to these food products.

Enterobacteriaceae are essential for the modulation of colitis severity by fungi.

BACKGROUND: Host-microbe balance maintains intestinal homeostasis and strongly influences inflammatory conditions such as inflammatory bowel diseases (IBD). Here we focused on bacteria-fungi interactions and their implications on intestinal inflammation, a poorly understood area. METHODS: Dextran sodium sulfate (DSS)-induced colitis was assessed in mice treated with vancomycin (targeting gram-positive bacteria) or colistin (targeting Enterobacteriaceae) and supplemented with either Saccharomyces boulardii CNCM I-745 or Candida albicans. Inflammation severity as well as bacterial and fungal microbiota compositions was monitored. RESULTS: While S. boulardii improved DSS-induced colitis and C. albicans worsened it in untreated settings, antibiotic treatment strongly modified DSS susceptibility and effects of fungi on colitis. Vancomycin-treated mice were fully protected from colitis, while colistin-treated mice retained colitis phenotype but were not affected anymore by administration of fungi. Antibacterial treatments not only influenced bacterial populations but also had indirect effects on fungal microbiota. Correlations between bacterial and fungal relative abundance were dramatically decreased in colistin-treated mice compared to vancomycin-treated and control mice, suggesting that colistin-sensitive bacteria are involved in interactions with fungi. Restoration of the Enterobacteriaceae population by administrating colistin-resistant Escherichia coli reestablished both beneficial effects of S. boulardii and pathogenic effects of C. albicans on colitis severity. This effect was at least partly mediated by an improved gut colonization by fungi. CONCLUSIONS: Fungal colonization of the gut is affected by the Enterobacteriaceae population, indirectly modifying effects of mycobiome on the host. This finding provides new insights into the role of inter-kingdom functional interactions in intestinal physiopathology and potentially in IBD.

Seven cases of Saccharomyces fungaemia related to use of probiotics.

Probiotics are increasingly used in critically ill patients without enough safety data. The aim of the present study was to determine the association of probiotics with Saccharomyces cerevisiae fungaemia. Seven patients with S. cerevisiae fungaemia were reported at two hospitals in India between July 2014 and September 2015. Detailed clinical history of patients was recorded. Besides the seven patient isolates, three probiotics sachets used in those patients and five unrelated clinical isolates were used for association study by Fluorescent amplified fragment length polymorphism (FAFLP). Antifungal susceptibility testing was performed by broth microdilution technique of CLSI (M27-A3) and interpreted according to CLSI (M27S4). Two patients were premature neonates and five were adults. They were admitted in intensive care unit and were on probiotics containing S. boulardii (except one adult patient). FAFLP analysis showed 96.4-99.7% similarity between blood and corresponding probiotic isolates. Of the three AFLP types (group I, II, II) identified, all the probiotic isolates clustered in group I (major cluster) including majority of the blood isolates. The isolates were susceptible to all antifungal agents tested. Five patients, who could be evaluated, responded promptly to echinocandins or voriconazole. As the prescription of probiotic containing S. boulardii in critically ill patient's leads to the fungaemia, we recommend avoiding this probiotic in those patients.

Saccharomyces boulardii probiotic-associated fungemia: questioning the safety of this preventive probiotic's use.

We report a case of fungemia in an immunocompetent patient after administration of probiotic containing Saccharomyces boulardii. We demonstrated the strain relatedness of the yeast from the probiotic capsule and the yeast causing fungal infection using genomic and proteomic typing methods. Our study questions the safety of this preventative biotherapy.