Selective enrichment of commensal gut bacteria protects againstCitrobacter rodentium-induced colitis

Abstract

The intestinal microbiota plays a key role in shaping the host immune system. Perturbation of gut microbial composition, termed dysbiosis, is associated with an increased susceptibility to intestinal pathogens and is a hallmark of a number of inflammatory, metabolic, and infectious diseases. The prospect of mining the commensal gut microbiota for bacterial strains that can impact immune function represents an attractive strategy to counteract dysbiosis and resulting disease. In this study, we show that selective enrichment of commensal gut lactobacilli protects against the murine pathogen Citrobacter rodentium, a well-characterized model of enteropathogenic and enterohemorrhagic Escherichia coli infection. The lactobacilli-enriched bacterial culture prevented the expansion of Gammaproteobacteria and Actinobacteria and was associated with improved indexes of epithelial barrier function (dextran flux), transmissible crypt hyperplasia, and tissue inflammatory cytokine levels. Moreover, cultivation of gut bacteria from Citrobacter rodentium-infected mice reveals the differential capacity of bacterial subsets to mobilize neutrophil oxidative burst and initiate the formation of weblike neutrophil extracellular traps. Our findings highlight the beneficial effects of a lactobacilli-enriched commensal gut microenvironment and, in the context of an intestinal barrier breach, the ability of neutrophils to immobilize both commensal and pathogenic bacteria.

Perfluorooctane sulfonate affects intestinal immunity against bacterial infection

“…Previous reports have suggested the colonization of C. rodentium is associated with distribution of commensal flora in the gut 42–45 . And dysbiosis may cause increase of susceptibility to C. rodentium infection 46 .…”

“…6F). We further analyzed 4 types of bacterial species in the Lactobacillus genus, which has been shown to play regulatory roles during intestinal inflammation 42–45 . We found Lactobacillus johnsonni and Lactobacillus casei decreased in PFOS treated mice at late but not early phase of infection, while Lactobacillus acidophilus and Lactobacillus reuteri was not affected by PFOS at both early and late phase of the infection (Fig.…”

Human Milk Oligosaccharides Increase Mucin Expression in Experimental Necrotizing Enterocolitis

“…Transwell plates were then incubated at 37 °C for 5 h, and 50 µL aliquots collected from the basolateral compartment to quantify fluorescence signal intensities using 700 nm (emission) channel with an infrared imaging system (Odyssey, LI‐COR Biosciences, Lincoln, NE). For in vivo mucosal‐to‐blood permeability, serum recovery of 4 kDa FITC‐dextran was performed as previously described . Briefly, pups were orogastrically gavaged 150 µL FITC‐dextran and whole blood was collected after 4 h. Quantification of FITC‐dextran permeability was assessed by calculating a serial dilution curve with known concentrations of FITC‐dextran.…”

Pomegranate peel extract alters the microbiome in mice and dysbiosis caused by Citrobacter rodentium infection

“…Fecal transplant experiments demonstrated that highly susceptible mice can be rendered less susceptible by transplantation of the microbiome from resistant mice (Ghosh et al, 2011;Willing, Vacharaksa, Croxen, Thanachayanont, & Finlay, 2011). Administration of a Lactobacilli-enriched culture to mice reduced Cr disease severity (Vong, Pinnell, Maattanen, & Yeung, 2015) while dysbiosis induced by feeding a fiber-free diet exacerbated disease activity (Desai et al, 2016). Thus, the microbiome plays a key role in determining Cr disease severity.…”