It is estimated that almost 4% of all neonatal intensive care unit admissions are attributed to Candida spp. infections. Clinical diagnosis of invasive fungal infection (IFI) is not easy as signs and symptoms are commonly vague. Mannan antigen (MA) in neonates is not well studied and the aim of this study was to evaluate the use of MA (Platelia™ Candida Ag Plus kit, Bio-Rad) in a neonatal unit. This is a prospective case-control study, which compared the performance of MA between neonates who had rectal Candida colonization with non-colonized controls. We cultured 340 rectal swabs of neonates and 39 of them were positive for Candida albicans colonization. MA was checked in 25 C. albicans colonized and in 30 non-colonized neonates with similar postnatal age and gender distribution. During the hospitalization period there was not any IFI in the neonatal population. MA was negative in all non-colonized neonates (30/30, 100% specificity) and in 24 out of 25 colonized neonates (96% specificity). However, the one infant with positive rectal colonization and MA had recent Candida mucositis. The results indicate a high specificity of the assay even in neonates colonized with Candida. Further investigation in neonates with IFI is required in order to determine the sensitivity of the method.

Yeast, crucial in beer production, holds promise as a valuable by-product resource, known as brewer's spent yeast (BSY), with potentially beneficial physiological effects. This study aimed to compare the composition and soluble polysaccharide content of Brewer's spent yeast with those of pure cultured yeast strains, namely Saccharomyces cerevisiae (SC) and S. boulardii (SB), to facilitate the utilization of BSY as an alternative source of functional polysaccharides. BSY exhibited significantly higher carbohydrate content and lower crude protein content than SC and SB cells. The residues recovered through autolysis were 53.11%, 43.83%, and 44.99% for BSY, SC, and SB, respectively. Notably, the polysaccharide content of BSY residue (641.90 μg/mg) was higher than that of SC (553.52 μg/mg) and SB (591.56 μg/mg). The yields of alkali-extracted water-soluble polysaccharides were 40%, 30%, and 35% for BSY, SC, and SB, respectively, with BSY comprising a higher proportion of water-soluble saccharides than SC and SB, including 49.3% mannan and 20.1% β-glucan. Furthermore, BSY demonstrated antioxidant activities, including superoxide dismutase (SOD), ABTS, and DPPH scavenging potential, suggesting its ability to mitigate oxidative stress. BSY also exhibited a significantly higher total phenolic compound content, indicating its potential as an effective functional food material.

The ability of recombinant, SARS-CoV-2 Spike (S) protein to modulate the production of two COVID-19 relevant, pro-inflammatory cytokines (IL-6 and IFN-γ) in PBMC cultures of healthy, pre-Covid-19 subjects was investigated. We observed that cytokine production was largely and diversely modulated by the S protein depending on antigen or mitogen stimulation, as well as on the protein source, insect (S-in) or human (S-hu) cells. While both proteins co-stimulated cytokine production by polyclonally CD3-activated T cells, PBMC activation by the mitogenic lectin Concanavalin A (Con A) was up modulated by S-hu protein and down-modulated by S-in protein. These modulatory effects were likely mediated by the S glycans as demonstrated by direct Con A-S binding experiments and use of yeast mannan as Con A binder. While being ineffective in modulating memory antigenic T cell responses, the S proteins and mannan were able to induce IL-6 production in unstimulated PBMC cultures and upregulate the expression of Mannose Receptor (CD206), a marker of anti-inflammatory M2 macrophage. Our data point to a relevant role of N-glycans, particularly N-mannosidic chains, decorating the S protein in the immunomodulatory effects here reported. These novel biological activities of the S glycan ectodomain may add to the comprehension of Covid-19 pathology and immunity to SARS-CoV-2.