The relationship between Helicobacter pylori motility, morphology and phase of growth: implications for gastric colonization and pathology

Abstract

To explore the relationship between Helicobacter pylori motility, morphology and phase of growth, bacteria were isolated from antral biopsies of patients with duodenal ulcer or non-ulcer dyspepsia, and grown in liquid medium in batch and continuous culture systems. Motilities and morphologies of H. pylori in different phases of growth were examined with a Hobson BackTracker and by transmission electron microscopy. Morphologies of bacteria grown in vitro were also compared with those of bacteria in antral biopsies from patients with non-autoimmune gastritis. H. pylori had poor motility in lag phase, became highly motile in mid-exponential phase and lost motility in the decline phase of growth. Motilities of bacteria in the same phase of growth from patients with duodenal ulcer or non-ulcer dyspepsia were not significantly different. In the mid/late-exponential phase of growth bacteria had helical morphologies and multiple polar flagella, typical of H. pylori in the gastric mucus layer. In the decline phase of growth bacteria shed flagella, and had precoccoidal or coccoidal morphologies. These findings support the view that helical and coccoidal H. pylori are in different phases of growth with different roles in gastric colonization, indicate that bacterial motility per se is unlikely to be a determinant of H. pylori pathology, and suggest that H. pylori in the antral mucus layer is in a state of continuous (exponential phase) growth.

Expression of Surfactant Protein D in the Human Gastric Mucosa and duringHelicobacter pyloriInfection

“…While some reports suggest that there may be a specific SP-D receptor on neutrophils and macrophages, this idea is controversial, and other studies suggest that SP-D does not act as an opsonin (1,12). Motility is thought to be an important virulence determinant in H. pylori, allowing the organism to migrate to suitable niches within the gastric mucosa; inhibition of motility prevents colonization (6,31). In these experiments, motility was significantly inhibited even in the absence of agglutination.…”

Helicobacter pylori moves through mucus by reducing mucin viscoelasticity

“…3). From these images, the helical pitch, p, and radius, r, of the flagella bundle were measured to be 2.1 m and 0.57 m, respectively, and the length, L, of the flagella to be 3.2 m. Although the individual filaments, of 20-25 nm in diameter (36,37), that comprise the polar flagella bundle are challenging to image, the bundle of 4-6 filaments is clearly discernible (Fig. 3).…”

tlpA gene expression is required for arginine and bicarbonate chemotaxis in Helicobacter pylori

“…Mucus is continuously secreted by surface epithelial cells of the gastric glands and is degraded at the luminal surface of the mucus layer (Schreiber and Scheid, 1997). Because of a rapid mucus turnover, H. pylori cells need motility and spatial orientation to avoid being dragged into the lumen, where the acidic pH inhibits growth and paralyzes cell motility (Schreiber et al, 1999;Worku et al, 1999). Accordingly, orientation plays a central role both in acute colonization and chronic persistence of H. pylori.…”