Prevalence and molecular characterization of Clostridium difficile isolated from feedlot beef cattle upon arrival and mid-feeding period

<p>Abstract</p> <p>Background</p> <p>The presence of indistinguishable strains of <it>Clostridium difficile </it>in humans, food animals and food, as well as the apparent emergence of the food-animal-associated ribotype 078/toxinotype V as a cause of community-associated <it>C. difficile </it>infection have created concerns about the potential for foodborne infection. While studies have reported <it>C. difficile </it>in calves, studies of cattle closer to the age of harvest are required. Four commercial feedlots in Alberta (Canada) were enrolled for this study. Fecal samples were collected at the time of arrival and after acclimation (< 62, 62-71 or > 71 days on feed). Selective culture for <it>Clostridium difficile </it>was performed, and isolates were characterized by ribotyping and pulsed-field gel electrophoresis. A logistic regression model was built to investigate the effect of exposure to antimicrobial drugs on the presence of <it>C. difficile</it>.</p> <p>Results</p> <p><it>Clostridium difficile </it>was isolated from 18 of 539 animals at the time of feedlot arrival (CI = 2.3-6.1) and from 18 of 335 cattle at mid-feeding period (CI = 2.9-13.1). Overall, there was no significant difference in the prevalence of <it>C. difficile </it>shedding on arrival versus mid-feeding period (<it>P </it>= 0.47). No association between shedding of the bacterium and antimicrobial administration was found (<it>P </it>= 0.33). All the isolates recovered were ribotype 078, a toxinotype V strain with genes encoding toxins A, B and CDT. In addition, all strains were classified as NAP7 by pulsed field gel electrophoresis (PFGE) and had the characteristic 39 base pairs deletion and upstream truncating mutation on the <it>tcd</it>C gene.</p> <p>Conclusions</p> <p>It is apparent that <it>C. difficile </it>is carried in the intestinal tracts of a small percentage of feedlot cattle arriving and later in the feeding period and that ribotype 078/NAP7 is the dominant strain in these animals. Herd management practices associated with <it>C. difficile </it>shedding were not identified, however further studies of the potential role of antimicrobials on <it>C. difficile </it>acquisition and shedding are required.</p

CD44 Plays a Functional Role in Helicobacter pylori-induced Epithelial Cell Proliferation

The cytotoxin-associated gene (Cag) pathogenicity island is a strain-specific constituent of Helicobacter pylori (H. pylori) that augments cancer risk. CagA translocates into the cytoplasm where it stimulates cell signaling through the interaction with tyrosine kinase c-Met receptor, leading cellular proliferation. Identified as a potential gastric stem cell marker, cluster-of-differentiation (CD) CD44 also acts as a co-receptor for c-Met, but whether it plays a functional role in H. pylori-induced epithelial proliferation is unknown. We tested the hypothesis that CD44 plays a functional role in H. pylori-induced epithelial cell proliferation. To assay changes in gastric epithelial cell proliferation in relation to the direct interaction with H. pylori, human- and mouse-derived gastric organoids were infected with the G27 H. pylori strain or a mutant G27 strain bearing cagA deletion (ΔCagA::cat). Epithelial proliferation was quantified by EdU immunostaining. Phosphorylation of c-Met was analyzed by immunoprecipitation followed by Western blot analysis for expression of CD44 and CagA. H. pylori infection of both mouse- and human-derived gastric organoids induced epithelial proliferation that correlated with c-Met phosphorylation. CagA and CD44 co-immunoprecipitated with phosphorylated c-Met. The formation of this complex did not occur in organoids infected with ΔCagA::cat. Epithelial proliferation in response to H. pylori infection was lost in infected organoids derived from CD44-deficient mouse stomachs. Human-derived fundic gastric organoids exhibited an induction in proliferation when infected with H. pylori, that was not seen in organoids pre-treated with a peptide inhibitor specific to CD44. In the wellestablished Mongolian gerbil model of gastric cancer, animals treated with CD44 peptide inhibitor Pep1, resulted in the inhibition of H. pylori-induced proliferation and associated atrophic gastritis. The current study reports a unique approach to study H. pylori interaction with the human gastric epithelium. Here, we show that CD44 plays a functional role in H. pyloriinduced epithelial cell proliferation

An anarchy of cultures: aesthetics and the changing school

It is the contention of this paper that schools are currently sandwiched between demands of the economy on one side and increasingly fundamentalist communities on the other; that schools need some degree of autonomy from each; that the greatest challenge of the century is how we can live together despite our differences; and that the only way of successfully meeting this challenge is for schools to put social justice at the heart of their activities, activities that are best informed by the cultivation of reasoned imagination &ndash; that is, by an aesthetic approach to the development of intellectual, social, cultural, economic and personal identities

Morality and progress:IR narratives on international revisionism and the status quo

Scholars debate the ambitions and policies of today’s ‘rising powers’ and the extent to which they are revising or upholding the international status quo. While elements of the relevant literature provide valuable insight, this article argues that the concepts of revisionism and the status quo within mainstream International Relations (IR) have always constituted deeply rooted, autobiographical narratives of a traditionally Western-dominated discipline. As ‘ordering narratives’ of morality and progress, they constrain and organize debate so that revisionism is typically conceived not merely as disruption, but as disruption from the non-West amidst a fundamentally moral Western order that represents civilizational progress. This often makes them inherently problematic and unreliable descriptors of the actors and behaviours they are designed to explain. After exploring the formations and development of these concepts throughout the IR tradition, the analysis is directed towards narratives around the contemporary ‘rise’ of China. Both scholarly and wider political narratives typically tell the story of revisionist challenges China presents to a US/Western-led status quo, promoting unduly binary divisions between the West and non-West, and tensions and suspicions in the international realm. The aim must be to develop a new language and logic that recognize the contingent, autobiographical nature of ‘revisionist’ and ‘status quo’ actors and behaviours

Muc5b Is the Major Polymeric Mucin in Mucus from Thoroughbred Horses With and Without Airway Mucus Accumulation

Mucus accumulation is a feature of inflammatory airway disease in the horse and has been associated with reduced performance in racehorses. In this study, we have analysed the two major airways gel-forming mucins Muc5b and Muc5ac in respect of their site of synthesis, their biochemical properties, and their amounts in mucus from healthy horses and from horses with signs of airway mucus accumulation. Polyclonal antisera directed against equine Muc5b and Muc5ac were raised and characterised. Immunohistochemical staining of normal equine trachea showed that Muc5ac and Muc5b are produced by cells in the submucosal glands, as well as surface epithelial goblet cells. Western blotting after agarose gel electrophoresis of airway mucus from healthy horses, and horses with mucus accumulation, was used to determine the amounts of these two mucins in tracheal wash samples. The results showed that in healthy horses Muc5b was the predominant mucin with small amounts of Muc5ac. The amounts of Muc5b and Muc5ac were both dramatically increased in samples collected from horses with high mucus scores as determined visually at the time of endoscopy and that this increase also correlated with increase number of bacteria present in the sample. The change in amount of Muc5b and Muc5ac indicates that Muc5b remains the most abundant mucin in mucus. In summary, we have developed mucin specific polyclonal antibodies, which have allowed us to show that there is a significant increase in Muc5b and Muc5ac in mucus accumulated in equine airways and these increases correlated with the numbers of bacteria

Familie und Schule: zwei Orte der Erziehung.

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