An ultrastructural study of Helicobacter mustelae and evidence of a specific association with gastric mucosa.

The ultrastructure of Helicobacter mustelae, a natural inhabitant of the ferret stomach, has been studied and compared with the human gastroduodenal pathogen H. pylori. H. mustelae is a short, slightly curved rod, 2 microns x 0.5 micron, with four or more sheathed flagella. The most common flagellar configuration is a single flagellum at one terminus, bipolar arrangement at the other end and a lateral flagellum. Dense inclusion bodies were observed below the flagellar insertion sites. It is suggested that this configuration is a specialised adaptation to motility in a viscous environment. On examination of the ferret gastric mucosa, similarities to H. pylori were observed such as adherence to gastric tissue and the formation of adhesion pedestals. However, unlike H. pylori, significant numbers of bacteria were intracellular. Furthermore, a much greater proportion of H. mustelae were attached to the mucosa with few bacteria lying free in the mucus, as is seen with H. pylori. It is concluded that the ferret is an important model for the study of adherence of bacteria to gastric mucosa and their possible role in peptic ulceration.