Journal: Gut pathogens
The role of the gut microbiome in human health and disease with a particular emphasis on therapeutic use of probiotics under specific medical conditions was mainly highlighted in 1st Annual conference of Probiotic Association of India (PAi) and International Symposium on “Probiotics for Human Health - New Innovations and Emerging Trends” held on 27th-28th August, 2012 at New Delhi, India. There is increasing recognition of the fact that dysbiosis or alteration of this gut microbiome may be implicated in gastro-intestinal disorders including diarrheal diseases, ulcerative colitis, inflammatory bowel diseases, life style diseases viz. Diabetes Mellitus-2 and obesity etc. This report summarizes the proceedings of the conference and the symposium comprehensively. Although, research on probiotics has been continuing for the past few decades, the subject has been currently the major focus of attention across the world due to recent advances and new developments in genomics, transcriptomics, proteomics, metabolomics and emergence of new generation of high through put sequencing technologies that have immensely helped in understanding the probiotic functionality and mode of action from nutritional and health perspectives. There is now sufficient evidence backed up with good quality scientific clinical data to suggest that probiotic interventions could indeed be effective in various types of diarrheal diseases, other chronic gastrointestinal inflammatory disorders like pouchitis, necrotizing entero-colitis, allergic responses and lactose intolerance etc. This report makes a modest attempt to give all the stake holders involved in development of probiotic based functional/health foods an overview of the current status of probiotics research at the Global and National level. The most crucial issues that emerged from the lead talks delivered by the eminent speakers from India and abroad were the major focus of discussions in different plenary and technical sessions. By discussing some of these issues from scientific perspectives, the conference could achieve its prime objective of disseminating the current knowledge on the prospects of probiotics as potential biotherapeutics in the management of human health and diseases.
Motility helps many pathogens swim through the highly viscous intestinal mucus. Given the differing outcomes of Campylobacter concisus infection, the motility of eight C. concisus strains isolated from patients with Crohn’s disease (n=3), acute (n=3) and chronic (n=1) gastroenteritis and a healthy control (n=1) were compared. Following growth on solid or liquid media the eight strains formed two groups; however, the type of growth medium did not affect motility. In contrast, following growth in viscous liquid medium seven of the eight strains demonstrated significantly decreased motility. In media of increasing viscosities the motility of C. concisus UNSWCD had two marked increases at viscosities of 20.0 and 74.7 centipoises. Determination of the ability of UNSWCD to swim through a viscous medium, adhere to and invade intestinal epithelial cells showed that while adherence levels significantly decreased with increasing viscosity, invasion levels did not significantly change. In contrast, adherence to and invasion of UNSWCD to mucus-producing intestinal cells increased upon accumulation of mucus, as did bacterial aggregation. Given this aggregation, we determined the ability of the eight C. concisus strains to form biofilms, and showed that all strains formed biofilms. In conclusion, the finding that C. concisus strains could be differentiated into two groups based on their motility may suggest that strains with high motility have an increased ability to swim through the intestinal mucus and reach the epithelial layer.
Increased intestinal permeability and translocation of gut microbiota from the intestinal lumen to the systemic circulation predispose patients to various diseases and may be one of the main triggers thereof. The role of microbiota in increased intestinal permeability is under intensive investigation. Here, we studied alterations in the host and increased intestinal permeability as a direct effect of treatment with a bacteriophage cocktail. After 10 days of challenge, the rats showed weight loss, messy hair, and decreased activity. Additionally, they displayed a significantly elevated lactulose:mannitol ratio and the level of circulating immune complexes. To our knowledge, this study demonstrates for the first time that increased intestinal permeability may be induced by bacteriophages that affect the microbiota.
In recent years there has been a renewed interest concerning the ways in which the gastrointestinal tract – its functional integrity and microbial residents – might influence human mood (e.g. depression) and behavioral disorders. Once a hotbed of scientific interest in the early 20th century, this area lay dormant for decades, in part due to its association with the controversial term ‘autointoxication’. Here we review contemporary findings related to intestinal permeability, small intestinal bacterial overgrowth, lipopolysaccharide endotoxin (LPS) exposure, D-lactic acid, propionic acid, and discuss their relevance to microbiota and mental health. In addition, we include the context of modern dietary habits as they relate to depression, anxiety and their potential interaction with intestinal microbiota.
Rapid scientific and technological advances have allowed for a more detailed understanding of the relevance of intestinal microbiota, and the entire body-wide micro biome, to human health and well-being. Rodent studies have provided suggestive evidence that probiotics (e.g. lactobacillus and bifidobacteria) can influence behavior. More importantly, emerging clinical studies indicate that the administration of beneficial microbes, via supplementation and/or fecal microbial transplant (FMT), can influence end-points related to mood state (glycemic control, oxidative status, uremic toxins), brain function (functional magnetic resonance imaging fMRI), and mental outlook (depression, anxiety). However, despite the advances in the area of gastro-biological psychiatry, it becomes clear that there remains an urgent need to explore the value of beneficial microbes in controlled clinical investigations. With the history explored in this series, it is fair to ask if we are now on the cusp of major clinical breakthroughs, or are we merely in the quicksand of Autointoxication II?
Mental health disorders, depression in particular, have been described as a global epidemic. Research suggests that a variety of lifestyle and environmental changes may be driving at least some portion of the increased prevalence. One area of flourishing research involves the relationship between the intestinal microbiota (as well as the related functional integrity of the gastrointestinal tract) and mental health. In order to appreciate the recent scientific gains in this area, and its potential future directions, it is critical to review the history of the topic. Probiotic administration (e.g. Lactobacillus) and fecal microbiota transfer for conditions associated with depression and anxiety is not a new concept. Here, in the first of a 3-part series, we begin by reviewing the origins of the contemporary research, providing a critical appraisal of what has become a revisionist history of the controversial term ‘autointoxication’. We argue that legitimate interests in the gut-brain-microbiota connection were obscured for decades by its association with a narrow historical legacy. Historical perspectives provide a very meaningful context to the current state of the contemporary research as outlined in parts II and III.
The influence of resident gut microbes on xenobiotic metabolism has been investigated at different levels throughout the past five decades. However, with the advance in sequencing and pyrotagging technologies, addressing the influence of microbes on xenobiotics had to evolve from assessing direct metabolic effects on toxins and botanicals by conventional culture-based techniques to elucidating the role of community composition on drugs metabolic profiles through DNA sequence-based phylogeny and metagenomics. Following the completion of the Human Genome Project, the rapid, substantial growth of the Human Microbiome Project (HMP) opens new horizons for studying how microbiome compositional and functional variations affect drug action, fate, and toxicity (pharmacomicrobiomics), notably in the human gut. The HMP continues to characterize the microbial communities associated with the human gut, determine whether there is a common gut microbiome profile shared among healthy humans, and investigate the effect of its alterations on health. Here, we offer a glimpse into the known effects of the gut microbiota on xenobiotic metabolism, with emphasis on cases where microbiome variations lead to different therapeutic outcomes. We discuss a few examples representing how the microbiome interacts with human metabolic enzymes in the liver and intestine. In addition, we attempt to envisage a roadmap for the future implications of the HMP on therapeutics and personalized medicine.
The gut microbiota plays an essential role in health and disease of humans. Bacteriophages are the most abundant members of the gut virobiota and display great diversity. Phages can translocate through the mucosa to lymph and internal organs and play a role as regulators of the bacterial population in the gut. Increasing abundance of phages in the gut mucosa may reduce colonization by bacteria. Moreover, phages may have an immunomodulatory role in the immune response in the human gut. The role of phages in inflammatory bowel disease (IBD) remains unknown. Phages may take part in the development of IBD, but there are also data suggesting the protective role of phages in the gut of patients with IBD. Furthermore, recent data suggest that phages may mediate the beneficial effects of fecal microbiota transplantation (FMT). Therefore, evidence is accumulating to highlight the protective immunomodulating activity of the gut phages.
Unrelated spore-forming bacteria share unique characteristics stemming from the presence of highly resistant endospores, leading to similar challenges in health and disease. These characteristics are related to the presence of these highly transmissible spores, which are commonly spread within the environment and are implicated in host-to-host transmission. In humans, spore-forming bacteria contribute to a variety of pathological processes that share similar characteristics, including persistence, chronicity, relapses and the maintenance of the resistome. We first outline the necessity of characterizing the totality of the spore-forming bacteria as the sporobiota based on their unique common characteristics. We further propose that the collection of all genes of spore-forming bacteria be known as the sporobiome. Such differentiation is critical for exploring the cross-talk between the sporobiota and other members of the gut microbiota, and will allow for a better understanding of the implications of the sporobiota and sporobiome in a variety of pathologies and the spread of antibiotic resistance.
Hepatitis C virus (HCV) causes debilitating liver diseases, which may progress to cirrhosis and cancer, and claims 500,000 annual lives worldwide. While HCV epidemiology, pathophysiology, and therapy are being deeply studied, rare attention is given to reciprocal interactions between HCV infection , HCV-induced chronic liver diseases, and the human gut microbiome. As Egypt has the world’s highest prevalence of HCV infections, we launched this study to monitor differences in the gut microbial community composition of Egyptian HCV patients that may affect, or result from, the patients' liver state.