Morphological analysis of Helicobacter pylori from gastric biopsies and dental plaque by scanning electron microscopy

Helicobacter pylori is rarely cultured from sites other than the gastric mucosa. The morphology of H. pylori in the stomach and dental plaque of adult dyspeptic patients was investigated to determine whether a difference in morphology at these sites could explain the inability to culture the organism from the oral cavity. Five adult patients attending for an upper gastrointestinal endoscopy were investigated. Dental plaque and gastric antral biopsy samples were analysed by culture and polymerase chain reaction (PCR) both before and after immunomagnetic separation using polyclonal rabbit anti-H. pylori IgG. Bead:bacteria aggregates were then examined by scanning electron microscopy (SEM). Rod and coccoid forms of H. pylori were seen by SEM in all oral and gastric samples which were H. pylori PCR positive. Although rod and coccoid forms have previously been shown to be associated with the gastric mucosa, this is the first time H. pylori cells have been visualized in dental plaque.