Oral administration of Lactobacillus gasseri TMC0356 stimulates peritoneal macrophages and attenuates general symptoms caused by enteropathogenic Escherichia coli infection

Background: Enteropathogenic Escherichia coli (EPEC) is an important cause of diarrhea in human. This study was conducted to investigate the ability of orally administrated probiotic lactobacilli to protect hosts from EPEC infection via enhancement of immune responses. Methods: Lyophilized Lactobacillus gasseri TMC0356 (TMC0356) was orally administered to Institute of Cancer Research (ICR) mice and Sprague Dawley (SD) rats for 11 and 7 days, respectively. These tested mice and rats were intraperitoneally injected with EPEC. Body weight, general symptoms (piloerection, soft stool, diarrhea, and anal hyperemia), and mortality of the tested mice were observed. Peritoneal macrophages were extracted from peritoneal Cavity of tested rats, and their phagocytosis and cytokine production were analyzed. Results: Oral administration of TMC0356 accelerated the disappearance of general symptoms and reduced mortality of EPEC-infected mice in the early phase. Peritoneal macrophages from rats orally administered with TMC0356 showed significant increases in phagocytic activity (p < 0.05) and interleukin (IL)-6 production (p < 0.01) compared to those from control rats. Tumor necrosis factor-a and production of IL-1 beta, IL-10, and IL-12 slightly increased, although the changes were not statistically significant. Conclusion: These results suggest that some of selected probiotic lactobacilli may, at least partly, protect hosts from EPEC infection by the enhancement of innate immunity of host and attenuate symptoms caused by the infection. Copyright (C) 2012, Taiwan Society of Microbiology. Published by Elsevier Taiwan LLC. All rights reserved.