Helicobacter suis affects the health and function of porcine gastric parietal cells

The stomach of pigs at slaughter age is often colonized by Helicobacter (H.) suis, which is also the most prevalent gastric non-H. pylori Helicobacter (NHPH) species in humans. It is associated with chronic gastritis, gastric ulceration and other gastric pathological changes in both hosts. Parietal cells are highly specialized, terminally differentiated epithelial cells responsible for gastric acid secretion and regulation. Dysfunction of these cells is closely associated with gastric pathology and disease. Here we describe a method for isolation and culture of viable and responsive parietal cells from slaughterhouse pigs. In addition, we investigated the interactions between H. suis and gastric parietal cells both in H. suis-infected six-month-old slaughter pigs, as well as in our in vitro parietal cell model. A close interaction of H. suis and parietal cells was observed in the fundic region of stomachs from H. suis positive pigs. The bacterium was shown to be able to directly interfere with cultured porcine parietal cells, causing a significant impairment of cell viability. Transcriptional levels of Atp4a, essential for gastric acid secretion, showed a trend towards an up-regulation in H. suis positive pigs compared to H. suis-negative pigs. In addition, sonic hedgehog, an important factor involved in gastric epithelial differentiation, gastric mucosal repair, and stomach homeostasis, was also significantly up-regulated in H. suis positive pigs. In conclusion, this study describes a successful approach for the isolation and culture of porcine gastric parietal cells. The results indicate that H. suis affects the viability and function of this cell type

Genome sequence of Helicobacter heilmannii sensu stricto ASB1 isolated from the gastric mucosa of a kitten with severe gastritis

Here we report the genome sequence of Helicobacter heilmannii sensu stricto ASB1 isolated from the gastric mucosa of a kitten with severe gastritis. Helicobacter heilmannii sensu stricto has also been associated with gastric disease in humans. Availability of this genome sequence will contribute to the identification of genes involved in the pathogen’s virulence and carcinogenic properties

Salmonella Typhimurium interferes with the humoral immune response in pigs

Foodborne salmonellosis is one of the most important bacterial zoonotic diseases worldwide. Salmonella Typhimurium is the serovar most frequently isolated from slaughter pigs in Europe. Circumvention of the host’s immune system by Salmonella might contribute to persistent infection of pigs. We found that Salmonella Typhimurium strain 112910a, which is able to persist in pigs, was capable of downregulating the expression of major histocompatibility class II (MHC II) molecules on porcine alveolar macrophages (PAM) in a Salmonella pathogenicity island 2 (SPI-2) dependent way and that MHC II downregulation was Salmonella strain dependent. The MHC II downregulation capacity was abolished when bacteria were opsonized with Salmonella-specific antibodies. Furthermore, intracellular proliferation of Salmonella Typhimurium opsonized with Salmonella positive pig serum was significantly impaired compared to that of the bacteria opsonized with negative pig serum. In a subsequent in vivo experiment, Salmonella Typhimurium strain MB2216 that did not induce MHC II downregulation in vitro, was shed less and persisted less but induced earlier seroconversion in pigs than strain 112910a. From the in vitro data, it is proposed that Salmonella Typhimurium downregulates the humoral immune response to promote intracellular survival inside porcine macrophages, contributing to long-term Salmonella persistence in pigs. The fact that the less persistent strain MB2216 induced earlier seroconversion than strain 112910a is of major interest for Salmonella-monitoring programs primarily based on serology, since this indicates that more persisting strains are more likely to escape serological detection