Abstract: Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder with an estimated worldwide prevalence of 10–20%. IBS can be associated with severe gastrointestinal symptoms, including abdominal pain, bloating, and altered bowel function. Although the causes of IBS remain undefined, recent research has increasingly suggested roles for gut flora in IBS. These roles involve postinfectious IBS, which can occur after a single episode of acute gastroenteritis, and small intestinal bacterial overgrowth, in which elevated populations of aerobic and anaerobic bacteria cause abdominal pain and altered bowel function. More recently, potential roles for methanogens in contributing to IBS subtypes have also been identified. In this paper, we review the different mechanisms by which gut flora may contribute to IBS and also discuss the efficacy and safety of various antibiotic therapies for treating IBS symptoms.
Abstract: Traveler’s diarrhea (TD) is a crucial area for research, as it affects millions of tourists each year and creates a large economic burden. More than 60% of TD cases are caused by a variety of bacterial enteropathogens: diarrhea-producing Escherichia coli, Shigella, Campylobacter, Salmonella, Aeromonas, Plesiomonas, and noncholera Vibrios. Noroviruses are also an important cause of morbidity among travelers. Recent studies have identified host genetic risk factors associated with susceptibility to pathogen-specific TD. Prevention strategies should be emphasized, as all individuals with TD experience approximately 24 hours of disability and 5–10% experience chronic functional bowel disease. Poorly absorbed rifaximin provides protection for trips lasting 2 weeks or less. TD vaccines are also currently in development. All individuals planning trips to developing regions should be armed with 1 of the 3 agents that have shown efficacy for self-treatment of TD: ciprofloxacin (or levofloxacin), rifaximin, or azithromycin, depending upon the location of the trip. Although global epidemiologic changes in etiologic agents as well as antibiotic resistance patterns have been better understood recently, changes should be expected during the next decade due to new prevention and treatment approaches.