Cyclopropane fatty acid synthase mutants of probiotic human-derived Lactobacillus reuteri are defective in TNF inhibition

Abstract

Probiotics are live microorganisms that confer health benefits to the host when administered in adequate amounts. Many probiotic strains are now marketed to consumers and include organisms such as lactobacilli, streptococci, bifidobacteria, Escherichia coli Nissle 1917, and the yeast Saccharomyces cerevisiae strain, “Saccharomyces boulardii”. In general, probiotics are considered safe for human consumption based on previous clinical trials, epidemiological studies, and historical usage in fermented foods. A subset of these probiotics have been derived from commensal bacteria indigenous to Homo sapiens. One such indigenous Lactobacillus species, Lactobacillus reuteri, includes a variety of strains derived from human breast milk and the gastrointestinal tract. The mechanisms by which commensal-derived probiotics promote health and combat diseases are poorly understood. Possible mechanisms include improving nutrient absorption, pathogen exclusion, strengthening intestinal barrier function and regulation of the immune system. A better understanding of how probiotics influence health is critical to fully optimize the integrative physiology of commensal microbial communities and mammalian hosts.