Roland Bücker

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The probiotic Escherichia coli Nissle 1917 (EcN) is widely used to maintain remission in ulcerative colitis. This is thought to be mediated by various immunomodulatory and barrier-stabilizing effects in the intestine. In this study, the mechanisms of barrier modulation by EcN were studied in the human epithelial HT-29/B6 cell culture model.EcN supernatant(More)
BACKGROUND Aeromonads cause a variety of infections, including gastroenteritis, sepsis, and wound necrosis. Pathogenesis of Aeromonas hydrophila and its hemolysin has been characterized, but the mechanism of the epithelial barrier dysfunction is currently poorly understood. METHODS Human colon epithelial monolayers HT-29/B6 were apically inoculated with(More)
BACKGROUND Arcobacter butzleri causes watery diarrhea and bacteremia. Although, recently, more cases of diarrhea have been caused by Arcobacter species, very little is known about its pathogenesis, the identification of which is the aim of this study. METHODS Human HT-29/B6 colonic epithelial monolayers were apically inoculated with A. butzleri.(More)
Antibiotic therapy disrupts the human intestinal microbiota. In some patients rapid overgrowth of the enteric bacterium Klebsiella oxytoca results in antibiotic-associated hemorrhagic colitis (AAHC). We isolated and identified a toxin produced by K. oxytoca as the pyrrolobenzodiazepine tilivalline and demonstrated its causative action in the pathogenesis of(More)
Campylobacter concisus infections of the gastrointestinal tract can be accompanied by diarrhea and inflammation, whereas colonization of the human oral cavity might have a commensal nature. We focus on the pathophysiology of C. concisus and the effects of different clinical oral and fecal C. concisus strains on human HT-29/B6 colon cells. Six oral and eight(More)
Campylobacter (C.) is one of the most common food-borne pathogen causing bacterial enteric infections in humans. Consumption of meat and meat products that have been contaminated with Campylobacter are the major source of infection. Pigs are a natural reservoir of Campylobacter spp. with C. coli as the dominant species. Even though some studies focussed on(More)
Tick-borne encephalitis virus (TBEV) is one of the most important vector-borne viruses in Europe and Asia. Its transmission mainly occurs by the bite of an infected tick. However, consuming milk products from infected livestock animals caused TBEV cases. To better understand TBEV transmission via the alimentary route, we studied viral infection of human(More)
Yersinia enterocolitica is a common cause of acute gastroenteritis. This study aimed to clarify the mechanisms leading to barrier dysfunction and diarrhea. Exposure of human colonic HT-29/B6 cells to Y. enterocolitica resulted in a decrease in transepithelial resistance from 404±23 to 163±21 Ω cm² (P<0.001) in parallel with an increase in mannitol (182 Da)(More)
AIMS The pathogenic potential of Arcobacter butzleri isolates on human (HT-29/B6) and porcine epithelial (IPEC-J2) cells was investigated by in vitro assays. METHODS AND RESULTS Five of six A. butzleri isolates were able to adhere and invade HT-29/B6 cells while only four isolates adhered and two invaded IPEC-J2 cells. Two non- or poorly invasive A.(More)
OBJECTIVE α-Haemolysin (HlyA) influences host cell ionic homeostasis and causes concentration-dependent cell lysis. As a consequence, HlyA-producing Escherichia coli is capable of inducing 'focal leaks' in colon epithelia, through which bacteria and antigens translocate. This study addressed the role of HlyA as a virulence factor in the pathogenesis of(More)