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Bifidobacterium bifidum TMC3115 strain (TMC3115) was orally administrated to 47 subjects with mild hyperglycaemia and dyslipidaemia aged 45 to 75 years for 3 weeks. Blood samples were collected before and after intervention for profiling plasma total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol and triglyceride concentrations, as well as fasting blood glucose. Before and 3 and 4 weeks after intervention, the faecal samples were collected to analyse faecal microbiota using the sequencing of 16S rRNA genes with a next-generation sequencer. TMC3115 significantly decreased plasma TC and LDL-C levels of the tested subjects after intervention (P < 0.05). The frequencies of defaecation and faecal odour after the intervention and 1 week later were significantly better than at pre-intervention, respectively. TMC3115 administration increased Firmicutes, Bacteroides and Actinobacteria and decreases in Proteobacteria and Fusobacteria. There were significant increases in the proportions of Dorea and Lachnospira after the intervention (P < 0.05). TMC3115 also increased the level of Firmicutes and decreased that of Bacteroidetes 1 week after the intervention (P < 0.05). Serum triglycerides correlated negatively with the proportions of Bacteroidetes (R = - 0.21, P = 0.047) and Bacteroides (R = - 0.23, P = 0.029), while the relative abundance of Dialister of Firmicutes correlated negatively and significantly with the serum LDL-C (R = - 0.24, P = 0.022) and TC levels (R = - 0.22, P = 0.030). These results indicate that TMC3115 might exhibit beneficial effects on the serum cholesterol metabolism of subjects with dyslipidaemia through modulation of their intestinal microbiota. Trial registration: ChiCTR-OOC-16010271.

Recent studies have demonstrated that antibiotics/or probiotics administration in early life play key roles on modulating intestinal microbiota and the alterations might cause long-lasting consequences both physiologically and immunologically. We investigated the effects of early life ceftriaxone, vancomycin and Bifidobacterium bifidum TMC3115 (TMC3115) treatment on intestinal microbiota and immunity both in neonates and adults even after termination of antibiotics exposure. We found that ceftriaxone and vancomycin, but not TMC3115, significantly altered the intestinal microbiota, serum total IgE level, and the morphology and function of the intestinal epithelium in the neonatal mice. In the adult stages, the diversity and composition of the intestinal microbiota were significantly different in the antibiotic-treated mice, and ceftriaxone-treated mice exhibited significantly higher serum total IgE and OVA-specific IgE levels. TMC3115 significantly mitigated the alteration of intestinal microbiota caused by ceftriaxone not vancomycin. Antibiotics and TMC3115 can differently modulate intestinal microbiota and SCFAs metabolism, affecting the development and function of the immunity and intestinal epithelium to different degrees in neonatal mice. Neonatal ceftriaxone-induced abnormal intestinal microbiota, immunity and epithelium could last to adulthood partly, which might be associated with the enhancement of host susceptibility to IgE-mediated allergies and related immune responses, TMC3115 may protect against the side effects of antibiotic treatment, at least partly.

Background: The present study was conducted to investigate the possible association between gut microbes and immunity among healthy middle-aged and elderly individuals in southwest China. A total of 148 healthy adults aged ≥ 50 years were divided into two age groups: middle-aged group (50–59 years; n = 67, 54.13 ± 3.32) and elderly group (≥ 60 years; n = 81, 64.70 ± 3.93). Blood samples were collected to measure serum immune and biochemical indices. Gut microbiota compositions of the groups were characterized on the basis of faecal DNA using 16S rRNA gene sequencing. Results: Among the detected gut microbes, the presence of Alistipes was negatively correlated with age in both groups. In the middle-aged group, age was negatively correlated with the presence of Desulfovibrio and Faecalibacterium. In the elderly group, Coprococcus was present at significantly higher levels; age was negatively correlated with the presence of Lachnobacterium, Oxalobacter and the Chao index, whereas positively correlated with the presence of Sutterella. In the middle-aged group, the presence of Bacteroidetes was positively correlated with serum immunoglobulin G (IgG) levels and the percent of CD8+ T cells and negatively correlated with the CD4+/CD8+ ratio; the presence of Firmicutes was negatively correlated with IgM levels; Bacteroidetes/Firmicutes ratio was positively correlated with IgG and IgM levels and Simpson index was negatively correlated with the percent of CD8+ T cells and positively correlated with CD4+/CD8+ ratio. In the elderly group, the presence of Verrucomicrobia (identified as genus Akkermansia) was positively correlated with IgA levels and the percent of CD8+ T cells and negatively correlated with the percent of CD4+ T cells and CD4+/CD8+ ratio; the Chao index and observed species were positively correlated with IgA levels. Conclusions: These results indicated that ageing could significantly correlate with the composition of gut microbiota in terms of quantity and quality. Changes in gut microbiota caused by ageing, characterized by decreased Bacteroidetes levels, might be associated with immunosenescence among healthy middle-aged and elderly people in southwest China. [ABSTRACT FROM AUTHOR]