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Digital PCR-based Competitive Index for High-throughput Analysis of Fitness in Salmonella
Published on: May 13, 2019
The Bacteroides fragilis pathogenicity island links virulence and strain competition
Benjamin W Casterline1,2, Aaron L Hecht1,2, Vivian M Choi1,2
1a Department of Microbiology , University of Chicago , Chicago , IL , USA.
Abstract:
The mature microbiome is a stable ecosystem that resists perturbation despite constant host exposure to exogenous microbes. However, the microbial mechanisms determining microbiome development and composition are poorly understood. We recently demonstrated that a non-toxigenic B. fragilis (NTBF) strain restricts enteric colonization by an enterotoxigenic (ETBF) strain dependent on a type VI secretion system (T6SS). We show here that a second enterotoxigenic strain is competent to colonize, dependent on the Bacteroides fragilis pathogenicity island (BFPAI). Additional data showing complex environmental regulation of the Bacteroides fragilis toxin (BFT) suggest that virulence factors may be adapted to modify the colonic niche to provide a strain-specific colonization advantage. We conclude that more complex models of host-microbe-microbiome interactions are needed to investigate this hypothesis.
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