Recent developments and perspectives in the investigation of probiotic effects

The quest for a better understanding of how probiotics work has boosted an enormous interest in the molecular processes underlying host-microbe interactions. This review covers recent developments and perspectives in the study of probiotic mechanisms.     

Combined therapies to treat complex diseases: The role of the gut microbiota in multiple sclerosis

The commensal microbiota has emerged as an environmental risk factor for multiple sclerosis (MS). Studies in experimental autoimmune encephalomyelitis (EAE) models have shown that the commensal microbiota is an essential player in triggering autoimmune demyelination. Likewise, the commensal microbiota modulates the host immune system, alters the integrity and function of biological barriers and has a direct effect on several types of central nervous system (CNS)-resident cells. Moreover, a characteristic gut dysbiosis has been recognized as a consistent feature during the clinical course of MS, and the MS-related microbiota is gradually being elucidated. This review highlights animal studies in which commensal microbiota modulation was tested in EAE, as well as the mechanisms of action and influence of the commensal microbiota not only in the local milieu but also in the innate and adaptive immune system and the CNS. Regarding human research, this review focuses on studies that show how the commensal microbiota might act as a pathogenic environmental risk factor by directing immune responses towards characteristic pathogenic profiles of MS. We speculate how specific microbiome signatures could be obtained and used as potential pathogenic events and biomarkers for the clinical course of MS. Finally, we review recently published and ongoing clinical trials in MS patients regarding the immunomodulatory properties exerted by some microorganisms. Because MS is a complex disease with a large variety of associated environmental risk factors, we suggest that current treatments combined with strategies that modulate the commensal microbiota would constitute a broader immunotherapeutic approach and improve the clinical outcome for MS patients.     

Comparative genomic analysis for the presence of potential enterococcal virulence factors in the probiotic Enterococcus faecalis strain Symbioflor 1

Enterococci are members of the natural microbiota of animal and human intestinal tracts and are capable of causing opportunistic infections. They are also used as starter cultures in the food industry as well as in health supplements and probiotics by the pharmaceutical industry. This Janus-faced status requires a careful evaluation on the basis of pathogenic traits to ensure the safety of the strain used to produce food and pharmaceuticals. We performed gapped-genome sequencing of a probiotic strain Enterococcus faecalis Symbioflor 1 and present initial results deriving from comparative genome analysis with that of the previously sequenced pathogenic clinical isolate E. faecalis V583. There was strong overall conservation of synteny between both strains and a detailed analysis revealed the absence of large genomic regions from the chromosome of the probiotic strain, indicating gene loss. Genes absent from the Symbioflor 1 strain included those encoding the enterococcal cytolysin, enterococcal surface protein, and gelatinase (coccolysin) as well as hyaluronidase and the peptide antibiotic AS-48. This data was confirmed using PCR primers specific for the respective genes. However, other enterococcal determinants such as aggregation substance, collagen adhesion protein, the ability to resist oxygen anions as well as capsule formation were detected. The presence of these traits may be advantageous for the strain Symbioflor 1 since they potentially enable colonization and proliferation of the bacterium on mucosal surfaces thereby conferring on it probiotic traits.     

人体肠道菌群与抗生素应用

肠道菌群多指生活在人体小肠、结肠和盲肠的细菌群,种类超过1000种,基因数目超过人体100倍,是人体已知最 大的微生物群,与宿主的代谢健康密切相关。基因功能注释和代谢组学的成熟和推广,丰富了宿主与微生物组间的探索维度。 抗生素影响肠道菌群组成和抗生素耐药基因负荷,抗生素使用后肠道菌群形成新的稳态,干扰疾病和治疗进程,并与个体所处 的生长发育时期、抗生素种类和使用时长有关。菌群多样性和特性的细菌种类可能影响抗生素使用后肠道菌群的恢复。此 外,粪菌移植和益生菌补充用于抗生素干扰后肠道菌群的恢复尚无明确证据。“粪菌”和“肠道菌群”不能完全等价、小样本量和 难以控制的混杂因素是目前研究存在的主要不足,代谢组学的“归类”作用或将帮助解答上述问题。综上,本文就人体肠道菌 群与抗生素应用的研究进展展开综述。