Association Between Sulfur-Metabolizing Bacterial Communities in Stool and Risk of Distal Colorectal Cancer in Men.

Background & Aims: Sulfur-metabolizing microbes, which convert dietary sources of sulfur into genotoxic hydrogen sulfide (HS), have been associated with development of colorectal cancer (CRC). We identified a dietary pattern associated with sulfur-metabolizing bacteria in stool and then investigated its association with risk of incident CRC using data from a large prospective study of men.

Methods: We collected data from 51,529 men enrolled in the Health Professionals Follow-up Study since 1986 to determine the association between sulfur-metabolizing bacteria in stool and risk of CRC over 26 years of follow-up.

Modeling Host-Microbiome Interactions in .

The microbiome influences host processes including nutritional availability, development, immunity, and behavioral responses. is a powerful model to study molecular mechanisms of host-microbial interactions. Recent efforts have been made to profile the natural microbiome of , laying a foundation for mechanistic studies of host-microbiome interactions in this genetically tractable model system.

Administration of defined microbiota is protective in a murine Salmonella infection model.

Salmonella typhimurium is a major cause of diarrhea and causes significant morbidity and mortality worldwide, and perturbations of the gut microbiota are known to increase susceptibility to enteric infections. The purpose of this study was to investigate whether a Microbial Ecosystem Therapeutic (MET-1) consisting of 33 bacterial strains, isolated from human stool and previously used to cure patients with recurrent Clostridium difficile infection, could also protect against S. typhimurium disease.

Recurrent Clostridium difficile infection and the microbiome.

The diverse and densely populated gastrointestinal microbiota is essential for the regulation of host physiology and immune function. As our knowledge of the composition and function of the intestinal microbiota continues to expand, there is new interest in using these developments to tailor fecal microbiota transplantation (FMT) and microbial ecosystem therapeutics (MET) for a variety of diseases. The potential role of FMT and MET in the treatment of Clostridium difficile infection (CDI)-currently the leading nosocomial gastrointestinal infection-has proven highly effective for recurrent CDI, and has emerged as a paradigm shift in the treatment of this disease.

Giardia duodenalis-induced alterations of commensal bacteria kill Caenorhabditis elegans: a new model to study microbial-microbial interactions in the gut.

Giardia duodenalis is the most common cause of parasitic diarrhea worldwide and a well-established risk factor for postinfectious irritable bowel syndrome. We hypothesized that Giardia-induced disruptions in host-microbiota interactions may play a role in the pathogenesis of giardiasis and in postgiardiasis disease. Functional changes induced by Giardia in commensal bacteria and the resulting effects on Caenorhabditis elegans were determined.

Cathepsin B gene disruption induced Leishmania donovani proteome remodeling implies cathepsin B role in secretome regulation.

Leishmania cysteine proteases are potential vaccine candidates and drug targets. To study the role of cathepsin B cysteine protease, we have generated and characterized cathepsin B null mutant L. donovani parasites.