fumarates and Escherichia-coli-Infections

The mammalian gastrointestinal tract is a complex environment that hosts a diverse microbial community. To establish infection, bacterial pathogens must be able to compete with the indigenous microbiota for nutrients, as well as sense the host environment and modulate the expression of genes essential for colonization and virulence. Here, we found that enterohemorrhagic Escherichia coli (EHEC) O157:H7 imports host- and microbiota-derived L-malate using the DcuABC transporters and converts these substrates into fumarate to fuel anaerobic fumarate respiration during infection, thereby promoting its colonization of the host intestine. Moreover, L-malate is important not only for nutrient metabolism but also as a signaling molecule that activates virulence gene expression in EHEC O157:H7. The complete virulence-regulating pathway was elucidated; the DcuS/DcuR two-component system senses high L-malate levels and transduces the signal to the master virulence regulator Ler, which in turn activates locus of enterocyte effacement (LEE) genes to promote EHEC O157:H7 adherence to epithelial cells of the large intestine. Disruption of this virulence-regulating pathway by deleting either dcuS or dcuR significantly reduced colonization by EHEC O157:H7 in the infant rabbit intestinal tract; therefore, targeting these genes and altering physiological aspects of the intestinal environment may offer alternatives for EHEC infection treatment.

Topics: Animals; DNA-Binding Proteins; Enterohemorrhagic Escherichia coli; Escherichia coli Infections; Escherichia coli O157; Escherichia coli Proteins; Fumarates; Gene Expression Regulation, Bacterial; Humans; Intestines; Malates; Mammals; Microbiota; Protein Kinases; Rabbits

Monocytes can develop immunological memory, a functional characteristic widely recognized as innate immune training, to distinguish it from memory in adaptive immune cells. Upon a secondary immune challenge, either homologous or heterologous, trained monocytes/macrophages exhibit a more robust production of pro-inflammatory cytokines, such as IL-1β, IL-6, and TNF-α, than untrained monocytes.

Topics: Animals; Caenorhabditis elegans; Calcium Signaling; Cells, Cultured; Cytokines; Escherichia coli; Escherichia coli Infections; Fumarates; Host-Pathogen Interactions; Humans; Immunity, Innate; Immunologic Memory; Membrane Potential, Mitochondrial; Mitochondria; Mitochondrial Dynamics; Monocytes

The effect of feeding diets containing either spray-dried porcine plasma (SDPP) or pea protein-isolate (PPI) supplemented with either egg yolk antibodies (EYA) from hens immunized with enterotoxigenic Escherichia coli (ETEC) (K88 and F18) antigens, ZnO, fumaric acid (FA), or carbadox (AB) on pig performance, incidence of scours, and gut morphology was studied in a 14-d experiment. Ninety 10-d-old weaned pigs were assigned to six dietary treatments in a completely randomized design to give five pens per treatment with three pigs per pen. The diets were SDPP without EYA (SDPP - EYA), PPI without EYA (PPI - EYA), PPI with EYA (PPI + EYA), PPI with ZnO (PPI + ZnO), PPI with FA (PPI + FA), or PPI with AB (PPI + AB). Diets were formulated to similar nutrient levels, with AB, EYA, FA, and ZnO at 0.25, 0.5, 2.0, and 0.4% of the diet, respectively. Pigs were weighed and bled on d 0, 7, and 14 to determine plasma urea N (PUN). Pigs were orally challenged with a 6-mL dose of 10(10) cfu/mL ETEC (K88) on d 7. On d 14, three pigs per treatment were killed to obtain sections of the small intestine for histological measurements. Weekly feed intake, BW changes, and gain:feed were determined. Incidence of scours and scour scores were monitored and fecal swabs were taken before and after ETEC challenge for PCR test to detect ETEC (K88). Feeding SDPP or supplementing PPI-based diets with EYA, ZnO, FA, or AB did not affect (P > 0.05) ADG, ADFI (as-fed basis), or gain:feed throughout the study. However, pigs fed PPI - EYA tended to have lower (P = 0.08) ADFI during wk 2 (137.9 g/d) and lower (P < 0.10) ADG from d 0 to 14 (100.1 g/d) than those fed the SDPP - EYA (156.6 g/d), PPI + EYA (151.2 g/d), PPI + ZnO (158.9 g/ d), PPI + FA (155.4 g/d), and PPI + AB (152.6 g/d) diets. Although scours was evident in all pigs 8 h after the ETEC challenge, it lasted only 3 to 5 d in pigs fed SDPP or PPI supplemented with EYA, ZnO, FA, or AB. Pigs fed PPI - EYA continued to have severe diarrhea, resulting in 40% mortality vs. 13% or less in the other groups. The PCR results showed that 81% of PPI-fed pigs continued to shed ETEC K88 7 d after ETEC challenge. Pigs fed PPI-EYA had shorter villi (P < 0.05), reduced villi:crypt ratio (P < 0.003), and higher intestinal pH (P < 0.001) and PUN (P < 0.001) than those fed SDPP or PPI supplemented with EYA, ZnO, FA, and AB. In conclusion, SDPP, EYA, ZnO, FA, and AB may have provided passive control to ETEC (K88) infection and potentially enabled young

Topics: Animal Feed; Animal Nutritional Physiological Phenomena; Animals; Animals, Newborn; Anti-Bacterial Agents; Antibodies, Bacterial; Diarrhea; Egg Yolk; Escherichia coli; Escherichia coli Infections; Fumarates; Pisum sativum; Plant Proteins; Plasma; Random Allocation; Swine; Swine Diseases; Weaning; Weight Gain; Zinc Oxide

The purpose of this study was to evaluate under field conditions, the efficacy of mild organic acid solutions in the prevention of neonatal kid diarrhoea. At a goat farm, two experimental groups of approximately 120 kids each were formed. The kids of the first group were not submitted to any treatment and served as negative controls, whereas the kids of the second group received a solution of organic acids (Euroacid 50-L; Eurotec, Waterloo, Belgium) which was administered orally on the first and second day of life. Groups were compared with regard to the incidence of diarrhoea, its duration, and the mortality of the kids. The results showed that, in comparison with the control group, the morbidity, the mortality and the case fatality of the treated kids was significantly reduced (P < 0.05). Furthermore, the duration of diarrhoea per sick kid was markedly reduced in the acidifier-treated group in comparison with the control animals (P < 0.05). Cultures of the diarrhoeic faeces from kids indicated that enterotoxigenic strains of Escherichia coli, and more specifically strains that were positive for K88 and K99 antigens, were present in the particular farm. It was concluded that the administration of organic acids can be a helpful means in controlling scours in neonatal kids.

Topics: Administration, Oral; Animals; Animals, Newborn; Anti-Bacterial Agents; Dairying; Diarrhea; Escherichia coli Infections; Female; Fumarates; Goat Diseases; Goats; Solutions; Treatment Outcome