SACM - United Kingdom
Permanent URI for this collectionhttps://drepo.sdl.edu.sa/handle/20.500.14154/9667
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Item Restricted The Influence of Iron and Lignin on Molecules of the Gastrointestinal Microbiome and Its Effect on the Conjugation of Carbapenem Resistance Plasmids(University of Birmingham, 2022-09) Alharbi, Abdullah; Buckner, MichelleThe gastrointestinal microbiome has acted a reservoir for antibiotic resistance genes by harbouring favourable conditions for the the conjugative transfer of resistance plasmids. Resistance against carbapenems, the last resort β-lactam antibiotics, has been on the rise and is mainly mediated by the spread of carbapenemase-encoding plasmids by Klebsiella pneumoniae. Dietary intake of iron and iron chelators can modulate the metabolic and microbial profile of the gastrointestinal microbiome. This project focused on investigating the influence that molecules produced by the gastrointestinal microbiome might have on the conjugation of carbapenem resistance plasmids in K. pneumoniae in reaction to iron and lignin supplementation. A fluorescence reporter system was used to determine the effect of iron and lignin co-supplementation to an ex-vivo colonic supernatant on the conjugation of an endemic carbapenemase-encoding plasmid called pKp-QIL. This was followed by plating-based conjugation assays which measured the frequency of conjugation of a plasmid from clinical isolate called pCPE16_3 in an iron and lignin co-supplemented ex-vivo colonic supernatant. This project has revealed that lignin has no effect on the conjugation of resistance plasmids in iron- available gastrointestinal microbiome.18 0Item Restricted Enhancing iron bioavailability from cereals as a strategy to reduce iron deficiency: in vitro digestion studies and a randomised control trial in UK females(Saudi Digital Library, 2023-12-24) Arafsha, Sarah Mohammed; Sharp, PaulBackground and hypothesis: Iron deficiency (ID) is the most common nutritional deficiency worldwide, and progress towards prevention of this disorder is slow. Plant foods are important sources of minerals in the United Kingdom. For example, 50% of iron is provided by cereals and a further 15% by vegetables. However, physical encapsulation within plant cells and the presence of absorption inhibitors such as phytic acid limit the availability of iron from plants for absorption in the human small intestine. The overall hypothesis for this project is physical disruption of wheat flour cell walls will increase the release of iron (i.e. the bioaccessibility) from foods during digestion and thereby enhance the bioavailability of iron from wheat-based foods. If successful, this change in milling of flour may provide a strategy to reduce the incidence of ID. Materials and methods: Studies were carried out using wheat flour produced by either standard milling or by micro-milling to reduce flour particle size. Mineral content of foods were determined by ICP-OES. The effects of cooking (boiling and baking), digestive enzymes, and pH on iron bioaccessibility from wheat-based foods following in vitro digestion was measured by ICP-OES. Food digests were applied to intestinal Caco-2 cells and iron bioavailability was assessed using ICP-MS. A human study was also carried out to assess the bioavailability of iron wheat breads made from standard and micronized flour. Results and conclusion: Micro-milling reduced flour particle size by 3-times. Foods made from micronized flour had higher iron bioavailability. This was particularly evident following gastric digestion when pH was low. In summary, the results suggest that micro-milling may increase iron bioaccessibility and bioavailability of iron from wheat flour. If endogenous iron in wheat-based foods was more bioavailable this might decrease the incidence of ID seen in some population groups in the UK.14 0